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Psychology

Psychology

Overview
Psychology (Greek
Ancient Greek
Ancient Greek is the historical stage in the development of the Greek language spanning across the Archaic , Classical , and Hellenistic periods of ancient Greece and the ancient world. It is predated in the 2nd millennium BC by Mycenaean Greek...

: Ψυχολογία, lit. "study of the mind", from psukhē "breath, spirit, soul"; and , -logia "study of") is an academic and applied
Applied science
Applied science is the application of knowledge from one or more natural scientific fields to solve practical problems. Fields of engineering are closely related to applied sciences. Applied science is important for technology development. Its use in industrial settings is usually referred to as...

 discipline involving the systematic, and sometimes scientific
Science
Science is in its broadest sense to any systematic knowledge-base or prescriptive practice that is capable of resulting in a prediction or predictable type of outcome...

, study of human or animal mental function
Mental function
Mental process, mental functions and cognitive processes are terms often used interchangeably to mean such functions or processes as perception, introspection, memory, creativity, imagination, conception, belief, reasoning, volition, and emotion...

s and behavior
Behavior
Behavior or behaviour refers to the actions or reactions of an object or organism, usually in relation to the environment. Behavior can be conscious or subconscious, overt or covert, and voluntary or involuntary....

. Occasionally, in addition or opposition
Antipositivism
Antipositivism is the view in sociology that academics must necessarily reject empiricism and the scientific method in the conduct of social theory and research...

 to employing the scientific method
Scientific method
Scientific method refers to a body of techniques for investigating phenomena, acquiring new knowledge, or correcting and integrating previous knowledge. To be termed scientific, a method of inquiry must be based on gathering observable, empirical and measurable evidence subject to specific...

, it relies on symbol
Symbol
A symbol is something such as an object, picture, written word, sound, or particular mark that represents something else by association, resemblance, or convention. For example, a red octagon may stand for "STOP". On maps, crossed sabres may indicate a battlefield...

ic interpretation
Hermeneutics
Hermeneutics is the study of interpretation theory, and can be defined as either the art of interpretation, or the theory and practice of interpretation. Traditional hermeneutics - which includes Biblical hermeneutics - refers to the study of the interpretation of written texts, especially texts in...

 and critical analysis
Critical theory
Critical theory is the examination and critique of society and culture, drawing from knowledge across the social sciences and humanities. The term has two quite different meanings with different origins and histories, one originating in social theory and the other in literary criticism...

, albeit often less prominently than do other social sciences such as sociology
Sociology
Sociology is the scientific or systematic study of human societies. It is a branch of social science that uses various methods of empirical investigation and critical analysis to develop and refine a body of knowledge about human social structure and activity, often with the goal of applying such...

.

A professional theorist or practitioner of psychology is called a psychologist
Psychologist
A psychologist is someone who studies the human mind and behavior. Research psychologists study human perception, cognition, attention, emotion, motivation, personality, behavior and interpersonal relationships...

.
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Encyclopedia
Psychology (Greek
Ancient Greek
Ancient Greek is the historical stage in the development of the Greek language spanning across the Archaic , Classical , and Hellenistic periods of ancient Greece and the ancient world. It is predated in the 2nd millennium BC by Mycenaean Greek...

: Ψυχολογία, lit. "study of the mind", from psukhē "breath, spirit, soul"; and , -logia "study of") is an academic and applied
Applied science
Applied science is the application of knowledge from one or more natural scientific fields to solve practical problems. Fields of engineering are closely related to applied sciences. Applied science is important for technology development. Its use in industrial settings is usually referred to as...

 discipline involving the systematic, and sometimes scientific
Science
Science is in its broadest sense to any systematic knowledge-base or prescriptive practice that is capable of resulting in a prediction or predictable type of outcome...

, study of human or animal mental function
Mental function
Mental process, mental functions and cognitive processes are terms often used interchangeably to mean such functions or processes as perception, introspection, memory, creativity, imagination, conception, belief, reasoning, volition, and emotion...

s and behavior
Behavior
Behavior or behaviour refers to the actions or reactions of an object or organism, usually in relation to the environment. Behavior can be conscious or subconscious, overt or covert, and voluntary or involuntary....

. Occasionally, in addition or opposition
Antipositivism
Antipositivism is the view in sociology that academics must necessarily reject empiricism and the scientific method in the conduct of social theory and research...

 to employing the scientific method
Scientific method
Scientific method refers to a body of techniques for investigating phenomena, acquiring new knowledge, or correcting and integrating previous knowledge. To be termed scientific, a method of inquiry must be based on gathering observable, empirical and measurable evidence subject to specific...

, it relies on symbol
Symbol
A symbol is something such as an object, picture, written word, sound, or particular mark that represents something else by association, resemblance, or convention. For example, a red octagon may stand for "STOP". On maps, crossed sabres may indicate a battlefield...

ic interpretation
Hermeneutics
Hermeneutics is the study of interpretation theory, and can be defined as either the art of interpretation, or the theory and practice of interpretation. Traditional hermeneutics - which includes Biblical hermeneutics - refers to the study of the interpretation of written texts, especially texts in...

 and critical analysis
Critical theory
Critical theory is the examination and critique of society and culture, drawing from knowledge across the social sciences and humanities. The term has two quite different meanings with different origins and histories, one originating in social theory and the other in literary criticism...

, albeit often less prominently than do other social sciences such as sociology
Sociology
Sociology is the scientific or systematic study of human societies. It is a branch of social science that uses various methods of empirical investigation and critical analysis to develop and refine a body of knowledge about human social structure and activity, often with the goal of applying such...

.

A professional theorist or practitioner of psychology is called a psychologist
Psychologist
A psychologist is someone who studies the human mind and behavior. Research psychologists study human perception, cognition, attention, emotion, motivation, personality, behavior and interpersonal relationships...

. Psychologists study such phenomena as perception
Perception
In philosophy, psychology, and the cognitive sciences, perception is the process of attaining awareness or understanding of sensory information. It is a task far more complex than was imagined in the 1950s and 1960s, when it was predicted that building perceiving machines would take about a decade,...

, cognition
Cognition
Cognition is the scientific term for "the process of thought". Usage of the term varies in different disciplines; for example in psychology and cognitive science, it usually refers to an information processing view of an individual's psychological functions...

, attention
Attention
Attention is the cognitive process of selectively concentrating on one aspect of the environment while ignoring other things. Attention has also been referred to as the allocation of processing resources...

, emotion
Emotion
An emotion is a mental and physiological state associated with a wide variety of feelings, thoughts, and behavior. Emotions are subjective experiences, often associated with mood, temperament, personality, and disposition. The English word 'emotion' is derived from the French word émouvoir...

, motivation
Motivation
Motivation is the activation or energization of goal-oriented behavior. Motivation may be internal or external. The term is generally used for humans but, theoretically, it can also be used to describe the causes for animal behavior as well. This article refers to human motivation...

, personality
Personality psychology
Personality psychology is a branch of psychology that studies personality and individual differences.Its areas of focus include:* Constructing a coherent picture of a person and his or her major psychological processes...

, behavior
Behavior
Behavior or behaviour refers to the actions or reactions of an object or organism, usually in relation to the environment. Behavior can be conscious or subconscious, overt or covert, and voluntary or involuntary....

 and interpersonal relationships. Some, especially depth psychologists
Depth psychology
Depth psychology is a broad term that refers to any psychological approach examining the depth of human experience...

, also consider the unconscious mind
Unconscious mind
The unconscious mind is a term invented by the 18th century German romantic philosopher Ser Christopher Riegel and later introduced into English by the poet and essayist Samuel Taylor Coleridge...

. Psychologists attempt to understand the role of mental functions in individual and social behavior, while also exploring the underlying physiological
Psychophysiology
Psychophysiology the branch of psychology that is concerned with the physiological bases of psychological processes...

 and neurological
Neuropsychology
Neuropsychology is the basic scientific discipline that studies the structure and function of the brain related to specific psychological processes and overt behaviors. The term neuropsychology has been applied to lesion studies in humans and animals...

 processes.

Psychological knowledge
Knowledge
Knowledge is defined by the Oxford English Dictionary as expertise, and skills acquired by a person through experience or education; the theoretical or practical understanding of a subject, what is known in a particular field or in total; facts and information or awareness or familiarity gained...

 is applied to various spheres of human activity
Human behavior
Human behavior is the collection of behaviors exhibited by human beings and influenced by culture, attitudes, emotions, values, ethics, authority, rapport, hypnosis, persuasion, coercion and/or genetics....

 including the family, education
Educational psychology
Educational psychology is the study of how humans learn in educational settings, the effectiveness of educational interventions, the psychology of teaching, and the social psychology of schools as organizations. Educational psychology is concerned with how students learn and develop, often focusing...

, employment
Industrial and organizational psychology
Industrial and Organizational Psychology applies psychology to organizations and the workplace...

, and the treatment
Clinical psychology
Clinical psychology includes the scientific study and application of psychology for the purpose of understanding, preventing, and relieving psychologically-based distress or dysfunction and to promote subjective well-being and personal development...

 of mental health
Mental health
Mental health is a term used to describe either a level of cognitive or emotional well-being or an absence of a mental disorder. From perspectives of the discipline of positive psychology or holism mental health may include an individual's ability to enjoy life and procure a balance between life...

 problems. Psychology includes many sub-fields that span areas as diverse as human development
Developmental psychology
Developmental psychology, also known as human development, is the scientific study of systematic psychological changes that occur in human beings over the course of the life span. Originally concerned with infants and children, the field has expanded to include adolescence and adult development,...

, sports
Sport psychology
Sport psychology is the scientific study of people and their behaviors in sport contexts and the practical application of that knowledge. Sport psychologists identify principles and guidelines that professionals can use to help adults and children participate in and benefit from sport and exercise...

, health
Health psychology
Health psychology is concerned with understanding how biology, behavior, and social context influence health and illness. Health psychologists work alongside other medical professionals in clinical settings, work on behaviour change in public health promotion, teach at universities, and conduct...

, industry
Industrial and organizational psychology
Industrial and Organizational Psychology applies psychology to organizations and the workplace...

, media
Media Psychology
Media Psychology seeks an understanding of how people perceive, interpret, use, and respond to a media-rich world. In doing so, media psychologists can identify potential benefits and problems and promote the development positive media .-Some studies:...

 and law. Psychology incorporates research from the social sciences, natural sciences, and humanities
Humanities
The humanities are academic disciplines which study the human condition, using methods that are primarily analytic, critical, or speculative, as distinguished from the mainly empirical approaches of the natural and social sciences....

.

History



The study of psychology in philosophical
Philosophy
Philosophy is the study of general and fundamental problems concerning matters such as existence, knowledge, values, reason, mind, and language. Philosophy is distinguished from other ways of addressing these questions by its critical, generally systematic approach and its reliance on reasoned...

 context dates back to the ancient civilizations of Egypt
Ancient Egypt
Ancient Egypt was an ancient civilization of eastern North Africa, concentrated along the lower reaches of the Nile River in what is now the modern country of Egypt. The civilization coalesced around 3150 BC with the political unification of Upper and Lower Egypt under the first pharaoh, and...

, Greece
Ancient Greece
Ancient Greece is the civilisation belonging to the period of Greek history lasting from the Greek Dark Ages ca. 1100 BC and the Dorian invasion, to 146 BC and the Roman conquest of Greece after the Battle of Corinth. It is generally considered to be the seminal culture which provided the...

, China, India
History of India
The known history of India - the name in this context includes the areas now known as India, Pakistan and Bangladesh - begins with the Indus Valley Civilization, which spread and flourished in the north-western part of the Indian subcontinent, from c. 3300 to 1300 BCE. Its Mature Harappan period...

, and Persia. Psychology began adopting a more clinical
Clinical psychology
Clinical psychology includes the scientific study and application of psychology for the purpose of understanding, preventing, and relieving psychologically-based distress or dysfunction and to promote subjective well-being and personal development...

 and experimental
Experimental psychology
Experimental psychology is a methodological approach rather than a subject and encompasses varied fields within psychology. Experimental psychologists have traditionally conducted research, published articles, and taught classes on neuroscience, developmental psychology, sensation, perception,...

 approach under medieval Muslim psychologists
Islamic psychology
Islamic psychology or Ilm-al Nafsiat refers to the study of the Nafs in the Islamic world, particularly during the Islamic Golden Age as well as modern times , and is related to psychology, psychiatry and the neurosciences.Some of the advances in medieval Islamic...

 and physicians
Islamic medicine
In the history of medicine, Islamic medicine or Arabic medicine refers to medicine developed in the medieval Islamic civilization and written in Arabic, the lingua franca of the Islamic civilization. Despite these names, a significant number of scientists during this period were not Arab...

, who built psychiatric hospital
Psychiatric hospital
A psychiatric hospital, sometimes known as an asylum, is a hospital specializing in the treatment of serious mental illness, usually for relatively long-term inpatients....

s for such purposes.

In 1802, French physiologist Pierre Cabanis helped to pioneer biological psychology with his essay Rapports du physique et du moral de l'homme (On the relations between the physical and moral aspects of man). Cabanis interpreted the mind in light of his previous studies of biology
Biology
Biology is the natural science concerned with the study of life and living organisms, including their structure, function, growth, origin, evolution, distribution, and taxonomy...

, arguing that sensibility
Sensibility
Sensibility refers to an acute perception of or responsiveness toward something, such as the emotions of another. This concept emerged in eighteenth-century Britain, and was closely associated with studies of sense perception as the means through which knowledge is gathered...

 and soul
Soul
The soul, in many religions, spiritual traditions, and philosophies, is the spiritual and eternal part of a living being, commonly held to be separable in existence from the body; distinct from the physical part. It is typically thought to consist of ones consciousness and personality, and can be...

 are properties of the nervous system
Nervous system
The nervous system is a network of specialized cells that communicate information about an organism's surroundings and itself. It processes this information and causes reactions in other parts of the body. It is composed of neurons and other specialized cells called glial cells that aid in the...

.

Though the use of psychological experiment
Experiment
In scientific research, an experiment is a method of investigating causal relationships among variables, or to test a hypothesis. An experiment is a cornerstone of the empirical approach to acquiring data about the world and is used in both natural sciences and social sciences...

ation dates back to Alhazen's Book of Optics
Book of Optics
The Book of Optics was a seven-volume treatise on optics, physics, mathematics, anatomy and psychology written by the Iraqi Muslim scientist, Ibn al-Haytham , from 1011 to 1021, when he was under house arrest in Cairo, Egypt.The book...

in 1021, psychology as an independent experimental field of study began in 1879, when the German physician Wilhelm Wundt
Wilhelm Wundt
Wilhelm Maximilian Wundt was a German medical doctor, psychologist, physiologist, philosopher, and professor, known today as one of the founding figures of modern psychology. He is widely regarded as the "father of experimental psychology"...

 founded the first laboratory dedicated exclusively to psychological research at Leipzig University in Germany, for which Wundt is known as the "father of psychology". The year 1879 is thus sometimes regarded as the "birthdate" of psychology. The American philosopher and psychologist William James
William James
William James was a pioneering American psychologist and philosopher trained as a medical doctor. He wrote influential books on the young science of psychology, educational psychology, psychology of religious experience and mysticism, and the philosophy of pragmatism...

 published his seminal book, Principles of Psychology
Principles of Psychology
The Principles of Psychology is a monumental text in the history of psychology, written by William James and published in 1890.There were four methods in James' psychology: analysis , introspection , experiment The Principles of Psychology is a monumental text in the history of psychology, written...

in 1890, laying the foundations for many of the questions on which psychologist
Psychologist
A psychologist is someone who studies the human mind and behavior. Research psychologists study human perception, cognition, attention, emotion, motivation, personality, behavior and interpersonal relationships...

s would focus for years to come. Other important early contributors to the field include the German psychologist Hermann Ebbinghaus
Hermann Ebbinghaus
Hermann Ebbinghaus was a German psychologist who pioneered the experimental study of memory, and is known for his discovery of the forgetting curve and the spacing effect. He was also the first person to describe the learning curve...

 (1850–1909), a pioneer in the experimental study of memory
Memory
In psychology, memory is an organism's mental ability to store, retain, and recall information. Traditional studies of memory began in the fields of philosophy, including techniques of artificially enhancing the memory....

 at the University of Berlin; and the Russian physiologist
Physiology
Physiology is the science of the functioning of living systems. It is a subcategory of biology...

 Ivan Pavlov
Ivan Pavlov
Ivan Petrovich Pavlov was a Russian, and later Soviet, physiologist, psychologist, and physician. He was awarded the Nobel Prize in Physiology or Medicine in 1904 for research pertaining to the digestive system...

 (1849–1936) who investigated the learning
Learning
Learning is acquiring new knowledge, behaviors, skills, values, preferences or understanding, and may involve synthesizing different types of information. The ability to learn is possessed by humans, animals and some machines. Progress over time tends to follow learning curves.Human learning may...

 process now referred to as classical conditioning
Classical conditioning
Classical conditioning is a form of associative learning that was first demonstrated by Ivan Pavlov. The typical procedure for inducing classical conditioning involves presentations of a neutral stimulus along with a stimulus of some significance...

.

Starting in the 1950s, the experimental techniques set forth by Wundt, James, Ebbinghaus, and others would be reiterated as experimental psychology
Experimental psychology
Experimental psychology is a methodological approach rather than a subject and encompasses varied fields within psychology. Experimental psychologists have traditionally conducted research, published articles, and taught classes on neuroscience, developmental psychology, sensation, perception,...

 became increasingly cognitive
Cognition
Cognition is the scientific term for "the process of thought". Usage of the term varies in different disciplines; for example in psychology and cognitive science, it usually refers to an information processing view of an individual's psychological functions...

 (concerned with information
Information
Information as a concept has many meanings, from everyday usage to technical settings. The concept of information is closely related to notions of constraint, communication, control, data, form, instruction, knowledge, meaning, mental stimulus, pattern, perception, and representation.The English...

 and its processing
Information processing
Information processing is the change of information in any manner detectable by an observer. As such, it is a process which describes everything which happens in the universe, from the falling of a rock to the printing of a text file from a digital computer system...

) and, eventually, constituted a part of the wider cognitive science
Cognitive science
Cognitive science can be defined as the study of mind or the study of thought. It embraces multiple research disciplines, including psychology, artificial intelligence, philosophy, neuroscience, linguistics, anthropology, sociology and biology. It relies on varying scientific methodology Cognitive...

. In its early years, however, this development was seen as a "revolution"
Cognitive revolution
The cognitive revolution is the name for an intellectual movement in the 1950s that began what are known collectively as the cognitive sciences.It began in the modern context of greater interdisciplinary communication and research...

, as it both responded to and reacted against strains of thought—including psychodynamics
Psychodynamics
Psychodynamics is the systematized study and theory of the psychological forces that underlie human behavior, emphasizing the interplay between unconscious and conscious motivation.The original concept of "psychodynamics" was developed by Sigmund Freud...

 and behaviorism
Behaviorism
Behaviorism , also called the learning perspective , is a philosophy of psychology based on the proposition that all things which organisms do — including acting, thinking and feeling — can and should be regarded as behaviors...

—that had developed in the meantime.

Psychoanalysis



From the 1890s until his death in 1939, the Austrian physician Sigmund Freud
Sigmund Freud
Sigmund Freud , Sigismund Schlomo Freud , was an Austrian neurologist who founded the psychoanalytic school of psychology...

 developed a method of psychotherapy
Psychotherapy
Psychotherapy or personal counseling with a psychotherapist, is an intentional interpersonal relationship used by trained psychotherapists to aid a client or patient in problems of living.It aims to increase the individual's sense of their own well-being...

 known as psychoanalysis
Psychoanalysis
Psychoanalysis is a body of ideas developed by Austrian physician Sigmund Freud and continued by others. It is primarily devoted to the study of human psychological functioning and behavior, although it also can be applied to societies.
...

. Freud's understanding of the mind was largely based on interpretive methods, introspection
Introspection
Introspection is the self-observation and reporting of conscious inner thoughts, desires and sensations. It is a conscious mental and usually purposive process relying on thinking, reasoning, and examining one's own thoughts, feelings, and, in more spiritual cases, one's soul...

 and clinical observations, and was focused in particular on resolving unconscious conflict, mental distress and psychopathology
Psychopathology
Psychopathology is a term which refers to either the study of mental illness or mental distress, or the manifestation of behaviors and experiences which may be indicative of mental illness or psychological impairment, such as abnormal, maladaptive behavior or mental activity.Psychopathology is that...

. Freud's theories became very well-known, largely because they tackled subjects such as sexuality
Human sexuality
Human sexuality is how people experience the erotic and express themselves as sexual beings. Frequently driven by the desire for sexual pleasure, human sexuality has biological, physical and emotional aspects...

, repression
Psychological repression
Psychological repression, or simply repression, according to Sigmund Freud's psychoanalytic theory, is the involuntary psychological act of excluding desires and impulses from one's consciousness and holding or subduing them in the unconscious...

, and the unconscious mind
Unconscious mind
The unconscious mind is a term invented by the 18th century German romantic philosopher Ser Christopher Riegel and later introduced into English by the poet and essayist Samuel Taylor Coleridge...

 as general aspects of psychological development. These were largely considered taboo
Taboo
A taboo is a strong social prohibition relating to any area of human activity or social custom that is sacred and forbidden. Breaking the taboo is usually considered objectionable or abhorrent by society. The term comes from the Tongan language, and appears in many Polynesian cultures...

 subjects at the time, and Freud provided a catalyst for them to be openly discussed in polite society. Clinically, he helped to pioneer the method of free association
Free association (psychology)
Free association is a technique used in psychoanalysis, first developed by Sigmund Freud.In free association, psychoanalytic patients are invited to relate whatever comes into their minds during the analytic session, and not to censor their thoughts...

 and a therapeutic interest in dream
Dream
Dreams are a succession of images, thoughts, or emotions passing through the mind during sleep. The content and purpose of dreams are not fully understood, though they have been a topic of speculation and interest throughout recorded history. The scientific study of dreams is known as...

s.

Freud had a significant influence on Swiss psychiatrist Carl Jung
Carl Jung
Carl Gustav Jung was a Swiss psychiatrist, an influential thinker and the founder of analytical psychology known as Jungian psychology. Jung's approach to psychology has been influential in the field of depth psychology and in countercultural movements across the globe...

, whose analytical psychology
Analytical psychology
Analytical psychology is the school of psychology originating from the ideas of Swiss psychiatrist Carl Jung, and then advanced by his students and other thinkers who followed in his tradition. It is distinct from Freudian psychoanalysis but also has a number of similarities...

 became an alternative form of depth psychology
Depth psychology
Depth psychology is a broad term that refers to any psychological approach examining the depth of human experience...

. Other well-known psychoanalytic thinkers of the mid-twentieth century included Sigmund Freud's daughter psychoanalyst Anna Freud
Anna Freud
Anna Freud was the sixth and last child of Sigmund and Martha Freud. Born in Vienna, she followed the path of her father and contributed to the newly born field of psychoanalysis. With Melanie Klein, she is the cofounder of psychoanalytic child psychology...

, German-American psychologist Erik Erickson, Austrian-British psychoanalyst Melanie Klein
Melanie Klein
Melanie Klein was an Austrian-born British psychoanalyst who devised novel therapeutic techniques for children that had a significant impact on child psychology and contemporary psychoanalysis...

, English psychoanalyst and physician D. W. Winnicott
Donald Winnicott
Donald Woods Winnicott was an English paediatrician, psychiatrist, sociologist and psychoanalyst.-Early life and education:...

, German psychologist Karen Horney
Karen Horney
Karen Horney born Danielsen was a German psychoanalyst and psychiatrist of Norwegian and Dutch descent. Her theories questioned some traditional Freudian views, particularly his theory of sexuality, as well as the instinct orientation of psychoanalysis and its genetic psychology...

, German-born psychologist and philosopher Erich Fromm
Erich Fromm
Erich Seligmann Fromm was an internationally renowned social psychologist, psychoanalyst, humanistic philosopher, and democratic socialist. He was associated with what became known as the Frankfurt School of critical theory.-Punanni:Erich Fromm was born on 23 March 1900, at Frankfurt am Main, the...

, and English psychiatrist John Bowlby
John Bowlby
John Bowlby was a British psychiatrist and psychoanalyst, notable for his interest in child development and for his pioneering work in attachment theory.- Family background :...

. Throughout the 20th century, psychoanalysis evolved into diverse schools of thought, most of which may be classed as Neo-Freudian
Neo-Freudian
The Neo-Freudian psychologists were those followers of Sigmund Freud who accepted the basic tenets of his theory of psychoanalysis but altered it in some way...

.

Psychoanalytic theory and therapy were criticized by psychologists such as B. F. Skinner
B. F. Skinner
Burrhus Frederic Skinner was an American psychologist, author, inventor, advocate for social reform, and poet. He was the Edgar Pierce Professor of Psychology at Harvard University from 1958 until his retirement in 1974...

 and Hans Eysenck
Hans Eysenck
Hans Jürgen Eysenck was a British psychologist of German origin, best remembered for his work on intelligence and personality, though he worked in a wide range of areas...

, and by philosophers including Karl Popper
Karl Popper
Sir Karl Raimund Popper, CH, FRS, FBA was an Austrian and British philosopher and a professor at the London School of Economics. He is considered one of the most influential philosophers of science of the 20th century, and also wrote extensively on social and political philosophy...

. Skinner and other behaviorists
Behaviorism
Behaviorism , also called the learning perspective , is a philosophy of psychology based on the proposition that all things which organisms do — including acting, thinking and feeling — can and should be regarded as behaviors...

 believed that psychology should be more empirical
Empirical
The word empirical denotes information gained by means of observation, experience, or experiment. A central concept in science and the scientific method is that all evidence must be empirical, or empirically based, that is, dependent on evidence or consequences that are observable by the senses...

 and efficient than psychoanalysis, although they frequently agreed with Freud in ways that became overlooked as time passed. Popper, a philosopher of science
Philosophy of science
The philosophy of science is concerned with the assumptions, foundations, and implications of science. The field is defined by an interest in one of a set of "traditional" problems or an interest in central or foundational concerns in science...

, argued that Freud's, as well as Alfred Adler's
Alfred Adler
Alfred Adler was an Austrian medical doctor, psychologist and founder of the school of individual psychology. In collaboration with Sigmund Freud and a small group of Freud's colleagues, Adler was among the co-founders of the psychoanalytic movement as a core member of the Vienna Psychoanalytic...

, psychoanalytic theories included enough ad hoc
Ad hoc hypothesis
In science and philosophy, an ad hoc hypothesis is a hypothesis added to a theory in order to save it from being falsified. Ad hoc hypotheses compensate for anomalies not anticipated by the theory in its unmodified form. Scientists are often skeptical of theories that rely on frequent, unsupported...

 safeguards against empirical contradiction
Falsifiability
Falsifiability is the logical possibility that an assertion can be shown false by an observation or a physical experiment. That something is "falsifiable" does not mean it is false; rather, that if it is false, then this can be shown by observation or experiment. Falsifiability is an important...

 that the theories fell outside the realm of scientific inquiry. By contrast, Eysenck maintained that although Freudian ideas could be subjected to experimental science, they had not withstood experimental tests. By the 21st century
21st century
The 21st century is the current century of the Christian Era or Common Era in accordance with the Gregorian calendar. It began on January 1, 2001 and will end December 31, 2100...

, psychology departments in American universities had become experimentally oriented
Positivism
Positivism is a philosophy that holds that the only authentic knowledge is that which is based on actual sense experience. Metaphysical speculation is avoided...

, marginalizing Freudian theory and regarding it as a "desiccated and dead" historical artifact. Meanwhile, however, researchers in the emerging field of neuro-psychoanalysis
Neuro-Psychoanalysis
Neuro-psychoanalysis is a movement within neuroscience and psychoanalysis to combine the insights of both disciplines for a better understanding of mind and brain.-Theoretical Base: Dual Aspect Monism:...

 defended some of Freud's ideas on scientific grounds, while scholars of the humanities
Humanities
The humanities are academic disciplines which study the human condition, using methods that are primarily analytic, critical, or speculative, as distinguished from the mainly empirical approaches of the natural and social sciences....

 maintained that Freud was not a "scientist at all, but ... an interpreter
Hermeneutics
Hermeneutics is the study of interpretation theory, and can be defined as either the art of interpretation, or the theory and practice of interpretation. Traditional hermeneutics - which includes Biblical hermeneutics - refers to the study of the interpretation of written texts, especially texts in...

."

Behaviorism



Founded in the early 20th century by American psychologist John B. Watson
John B. Watson
John Broadus Watson is an American psychologist who established the psychological school of behaviorism, after doing research on animal behavior. He also conducted the controversial "Little Albert" experiment...

, behaviorism was embraced and extended by Americans Edward Thorndike
Edward Thorndike
Edward Lee Thorndike was an American psychologist who spent nearly his entire career at Teachers College, Columbia University. His work on animal behavior and the learning process led to the theory of connectionism and helped lay the scientific foundation for modern educational psychology...

, Clark L. Hull
Clark L. Hull
Clark Leonard Hull was an influential American psychologist who sought to explain learning and motivation by scientific laws of behavior. Born in Akron, New York, Hull obtained bachelor's and master's degrees from the University of Michigan, and in 1918 a PhD in from the University of...

, Edward C. Tolman
Edward C. Tolman
Edward Chace Tolman was an American psychologist. He was most famous for his studies on behavioral psychology.Born in West Newton, Massachusetts, brother of CalTech physicist Richard Chace Tolman, Edward C. Tolman studied at the Massachusetts Institute of Technology, and received his Ph.D. from...

, and later B. F. Skinner
B. F. Skinner
Burrhus Frederic Skinner was an American psychologist, author, inventor, advocate for social reform, and poet. He was the Edgar Pierce Professor of Psychology at Harvard University from 1958 until his retirement in 1974...

. Behaviorism reflected a belief that the methodology
Methodology
Methodology can be defined as:# "the analysis of the principles of methods, rules, and postulates employed by a discipline";# "the systematic study of methods that are, can be, or have been applied within a discipline"; or...

 behind laboratory-based animal experimentation, which was increasing in popularity as physiology
Physiology
Physiology is the science of the functioning of living systems. It is a subcategory of biology...

 grew more sophisticated, could provide useful psychosocial understanding of a type that comparatively subjective
Subject (philosophy)
In philosophy, a subject is a being which has subjective experiences, subjective consciousness or a relationship with another entity . A subject is an observer and an object is a thing observed...

 inquiries, such as psychodynamic analysis as employed by Freud or introspection
Introspection
Introspection is the self-observation and reporting of conscious inner thoughts, desires and sensations. It is a conscious mental and usually purposive process relying on thinking, reasoning, and examining one's own thoughts, feelings, and, in more spiritual cases, one's soul...

 as used by Wundt and James, could not.

The behaviorists shared with their predecessors a philosophical inclination toward positivism
Positivism
Positivism is a philosophy that holds that the only authentic knowledge is that which is based on actual sense experience. Metaphysical speculation is avoided...

 and determinism
Determinism
Determinism is the view that every event, including human cognition, behavior, decision, and action, is causally determined by an unbroken chain of prior occurrences. With numerous historical debates, many varieties and philosophical positions on the subject of determinism exist from...

. With Skinner, however, they entered into a line of thought, extending back to Austrian physicist and philosopher Ernst Mach
Ernst Mach
Ernst Mach was an Austrian physicist and philosopher, remembered for his contributions to physics such as the Mach number and the study of shock waves...

, which held that the research methods most faithful to their scientific orientation would yield "the pursuit of tools for the control of life problems rather than a search for timeless truths". The behaviorists argued that many contents of the mind were not open to scientific scrutiny and that scientific psychology should emphasize the study of observable behavior. Behaviorists focused on behavior-environment relations and analyzed overt and covert (i.e., private) behavior as a function of the organism interacting with its environment. Therefore, they often rejected or deemphasized dualistic
Dualism (philosophy of mind)
In philosophy of mind, dualism is a set of views about the relationship between mind and matter, which begins with the claim that mental phenomena are, in some respects, non-physical.Ideas on mind/body dualism originate at least as far back as Zarathushtra...

 explanations such as "mind" or "consciousness"; and, in lieu of probing an "unconscious mind" that underlies unawareness, they spoke of the "contingency-shaped behaviors" in which unawareness becomes outwardly manifest.

Among the behaviorists' most famous creations are Watson's Little Albert experiment
Little Albert experiment
The Little Albert experiment was an experiment showing empirical evidence of classical conditioning in humans. This study was also an example of stimulus generalization. It was conducted in 1920 by John B. Watson along with his assistant Rosalie Rayner. The study was done at Johns Hopkins...

, which applied classical conditioning to a human being, and Skinner's notion of operant conditioning
Operant conditioning
Operant conditioning is the use of consequences to modify the occurrence and form of behavior. Operant conditioning is distinguished from classical conditioning in that operant conditioning deals with the modification of "voluntary behavior" or operant behavior...

, which acknowledged that human agency could affect patterns and cycles of environmental stimuli and behavioral responses. American linguist Noam Chomsky
Noam Chomsky
Avram Noam Chomsky is an American linguist, philosopher, cognitive scientist, political activist, author, and lecturer. He is an Institute Professor and professor emeritus of linguistics at the Massachusetts Institute of Technology. Chomsky is well known in the academic and scientific community as...

's critique of the behaviorist model of language acquisition
Language acquisition
Language acquisition is the study of the processes through which humans acquire language. By itself, language acquisition refers to first language acquisition, which studies infants' acquisition of their native language, whereas second language acquisition deals with acquisition of additional...

 is regarded by many as a key factor in the decline of behaviorism's prominence. But Skinner's behaviorism has not died, perhaps in part because it has generated successful practical applications. The fall of behaviorism as an overarching model in psychology, however, gave way to a new dominant paradigm: cognitive approaches.

Humanism and existentialism



Humanistic psychology
Humanistic psychology
Humanistic psychology is a school of psychology that emerged in the 1950s in reaction to both behaviorism and psychoanalysis. It is explicitly concerned with the human dimension of psychology and the human context for the development of psychological theory....

 was developed in the 1950s in reaction to both behaviorism and psychoanalysis. By using phenomenology
Phenomenology (psychology)
In psychology, phenomenology is used to refer to subjective experiences or their study. The experiencing subject can be considered to be the person or self, for purposes of convenience. In phenomenological philosophy 'experience' is a considerably more complex concept than it is usually taken to...

, intersubjectivity and first-person categories, the humanistic approach sought to glimpse the whole person—not just the fragmented parts of the personality or cognitive functioning. Humanism focused on fundamentally and uniquely human issues, such as self-identity
Self-concept
Self-concept or self identity refers to the global understanding as well as the world around us and a sentient being has of him or herself. It presupposes but can be distinguished from self-consciousness, which is simply an awareness of one's self...

, death
Death
Death is the termination of the biological functions that define a living organism. It refers to both a particular event and to the condition that results thereby. The true nature of the latter has for millennia been a central concern of the world's religious traditions and of philosophical...

, aloneness, freedom
Free will
Free will raises the question whether, and in what sense, rational agents exercise control over their actions, decisions, choices. Addressing this question requires understanding the relationship between freedom and cause, and determining whether the laws of nature are causally deterministic...

, and meaning
Meaning (existential)
In existentialism, meaning is understood as the worth of life. Meaning in existentialism is unlike typical conceptions of "the meaning of life", because it is descriptive. Due to the method of existentialism, prescriptive or declarative statements about meaning are unjustified. Meaning is only...

. The humanistic approach was distinguished by its emphasis on subjective meaning, rejection of determinism, and concern for positive growth rather than pathology. Some of the founders of this school of thought were American psychologists Abraham Maslow
Abraham Maslow
Abraham Harold Maslow was an American psychologist. He is noted for his conceptualization of a "hierarchy of human needs", and is considered the founder of humanistic psychology.-Biography:...

, who formulated a hierarchy of human needs
Maslow's hierarchy of needs
Maslow's hierarchy of needs is a theory in psychology, proposed by Abraham Maslow in his 1943 paper A Theory of Human Motivation, which he subsequently extended to include his observations of humans' innate curiosity....

, and Carl Rogers
Carl Rogers
Carl Rogers was an influential American psychologist and among the founders of the humanistic approach to psychology...

, who created and developed client-centered therapy; and German-American psychiatrist Fritz Perls
Fritz Perls
Friedrich Salomon Perls , better known as Fritz Perls, was a noted German-born psychiatrist and psychotherapist of Jewish descent....

, who co-founded Gestalt therapy
Gestalt therapy
Gestalt therapy is an existential and experiential psychotherapy that focuses on the individual's experience in the present moment, the therapist-client relationship, the environmental and social contexts in which these things take place, and the self-regulating adjustments people make as a result...

. It became so influential as to be called the "third force" within psychology, along with behaviorism and psychoanalysis. Later, positive psychology
Positive psychology
Positive psychology is a recent branch of psychology that "studies the strengths and virtues that enable individuals and communities to thrive"...

 opened up humanistic themes to scientific modes of exploration.

Influenced largely by the work of German philosopher Martin Heidegger
Martin Heidegger
Martin Heidegger was an influential German philosopher. His best known book, Being and Time, is considered to be one of the most important philosophical works of the 20th century...

 and Danish philosopher Søren Kierkegaard
Søren Kierkegaard
Søren Aabye Kierkegaard was a prolific 19th century Danish philosopher and theologian. Kierkegaard strongly criticised both the Hegelianism of his time and what he saw as the empty formalities of the Church of Denmark...

, psychoanalytically-trained American psychologist Rollo May
Rollo May
Rollo May was an American existential psychologist. He authored the influential book Love and Will during 1969....

 pioneered an existential
Existentialism
Like “rationalism” and “empiricism,” “existentialism” is a term that belongs to intellectual history. Its definition is thus to some extent one of historical convenience...

 breed of psychology, which included existential therapy
Existential therapy
Existential psychotherapy is partly based on the existential belief that human beings are alone in the world. This feeling of aloneness leads to feelings of meaninglessness which can be overcome only by creating one's own values and meanings...

, in the 1950s and 1960s. Existential psychologists differed from others often classified as humanistic in their comparatively neutral view of human nature
Human nature
Human nature is the concept that there are a set of characteristics, including ways of thinking, feeling and acting, that all 'normal' humans have in common. The branches of science associated with the study of human nature include sociology, sociobiology and psychology, particularly...

 and in their relatively positive assessment of anxiety
Anxiety
Anxiety is a psychological and physiological state characterized by cognitive, somatic, emotional, and behavioral components. These components combine to create an unpleasant feeling that is typically associated with uneasiness, fear, or worry....

. Existential psychologists emphasized the humanistic themes of death, free will, and meaning, suggesting that meaning can be shaped by myths, or narrative patterns, and that it can be encouraged by an acceptance of the free will requisite to an authentic
Authenticity (philosophy)
Authenticity is a technical term in existentialist philosophy, and is also used in the philosophy of art and psychology. In philosophy, the conscious self is seen as coming to terms with being in a material world and with encountering external forces, pressures and influences which are very...

, albeit often anxious, regard for death and other future prospects. Austrian existential psychiatrist and Holocaust survivor Viktor Frankl
Viktor Frankl
Viktor Emil Frankl M.D., Ph.D. was an Austrian neurologist and psychiatrist as well as a Holocaust survivor. Frankl was the founder of logotherapy, which is a form of Existential Analysis, the "Third Viennese School of Psychotherapy"...

 drew evidence of meaning's therapeutic power from reflections garnered from his own internment
Internment
Internment is the imprisonment or confinement of people, commonly in large groups, without trial. The Oxford English Dictionary gives the meaning as: "The action of ‘interning’; confinement within the limits of a country or place"...

, and he created a variety of existential psychotherapy called logotherapy
Logotherapy
Logotherapy was developed by neurologist and psychiatrist Viktor Frankl. It is considered the "Third Viennese School of Psychotherapy" after Freud's psychoanalysis and Adler's individual psychology. It is a type of existentialist analysis that focuses on a will to meaning as opposed to Adler's...

. In addition to May and Frankl, Swiss psychoanalyst Ludwig Binswanger
Ludwig Binswanger
Ludwig Binswanger was a Swiss psychiatrist and pioneer in the field of existential psychology. His grandfather was founder of the "Bellevue Sanatorium" in Kreuzlingen, and his uncle Otto Binswanger was a professor of psychiatry at the University of Jena.In 1907 Binswanger received his medical...

 and American psychologist George Kelly
George Kelly (psychologist)
George Kelly was an American psychologist, therapist and educator, best known for developing Personal Construct Psychology.- Biography :...

 may be said to belong to the existential school.

Cognitivism



Noam Chomsky helped to ignite a "cognitive revolution
Cognitive revolution
The cognitive revolution is the name for an intellectual movement in the 1950s that began what are known collectively as the cognitive sciences.It began in the modern context of greater interdisciplinary communication and research...

" in psychology when he criticized the behaviorists' notions of "stimulus", "response", and "reinforcement", arguing that such ideas—which Skinner had borrowed from animal experiments in the laboratory—could be applied to complex human behavior, such as language acquisition, in only a vague and superficial manner. Chomsky emphasized that research and analysis must not ignore the innate contribution of the child to such behavior, while social learning theorists
Social learning theory
Social learning theory or SLT is the theory that people that learn new behavior through overt reinforcement or punishment, or via observational learning of the social factors in their environment...

 such as Albert Bandura
Albert Bandura
Albert Bandura is a psychologist specializing in social cognitive theory and self-efficacy. He is most famous for his social learning theory.- Education and academic career :...

 argued that the child's environment could make contributions of its own to the behaviors of an observant subject. The notion that behavior could be precipitated only by the functioning of an internal device
Language acquisition device
The Language Acquisition Device is a postulated "organ" of the brain that is supposed to function as a congenital device for learning symbolic language . First proposed by Noam Chomsky, the LAD concept is a component of the nativist theory of language...

 or by the perception of external surroundings posed a challenge to the behaviorist position that behavior is contingent upon the prior associations that individuals have made between behavioral responses and pleasurable or painful stimuli.

Meanwhile, accumulating technology
Technology
Technology is a broad concept that deals with human as well as other animal species' usage and knowledge of tools and crafts, and how it affects a species' ability to control and adapt to its environment...

 helped to renew interest and belief in the mental states and representations—i.e., the cognition
Cognition
Cognition is the scientific term for "the process of thought". Usage of the term varies in different disciplines; for example in psychology and cognitive science, it usually refers to an information processing view of an individual's psychological functions...

—that had fallen out of favor with behaviorists. English neuroscientist Charles Sherrington and Canadian psychologist Donald O. Hebb used experimental methods to link psychological phenomena with the structure and function of the brain
Brain
The brain is the center of the nervous system in all vertebrate, and most invertebrate, animals. Some primitive animals such as jellyfish and starfish have a decentralized nervous system without a brain, while sponges lack any nervous system at all...

. With the rise of computer science
Computer science
Computer science is the study of the theoretical foundations of information and computation, and of practical techniques for their implementation and application in computer systems. It is frequently described as the systematic study of algorithmic processes that create, describe and transform...

 and artificial intelligence
Artificial intelligence
Artificial intelligence is the intelligence of machines and the branch of computer science which aims to create it. Textbooks define the field as "the study and design of intelligent agents,"...

, analogies were drawn between the processing of information by humans and information processing
Information processing
Information processing is the change of information in any manner detectable by an observer. As such, it is a process which describes everything which happens in the universe, from the falling of a rock to the printing of a text file from a digital computer system...

 by machines. Research in cognition had proven practical since World War II
World War II
World War II, or the Second World War , was a global military conflict which involved a majority of the world's nations, including all great powers, organized into two opposing military alliances: the Allies and the Axis...

, when it aided in the understanding of weapons operation. By the late 20th century, though, cognitivism
Cognitivism (psychology)
In psychology, cognitivism is a theoretical approach in understanding the mind using quantitative, positivist and scientific methods, that describes mental functions as information processing models.-Theoretical approach:...

 had become the dominant paradigm
Paradigm
The word paradigm has been used in linguistics and science to describe distinct concepts....

 of mainstream psychology, and cognitive psychology
Cognitive psychology
Cognitive psychology is a discipline within psychology that investigates the internal mental processes of thought such as visual processing, memory, problem solving, and language....

 emerged as a popular branch.

Assuming both that the covert mind should be studied and that the scientific method should be used to study it, cognitive psychologists set such concepts as "subliminal processing
Subliminal message
A subliminal message is a signal or message embedded in another medium, designed to pass below the normal limits of the human mind's perception...

" and "implicit memory
Implicit memory
Implicit memory is a type of memory in which previous experiences aid in the performance of a task without conscious awareness of these previous experiences. Evidence for implicit memory arises in priming, a process whereby subjects show improved performance on tasks for which they have been...

" in place of the psychoanalytic "unconscious mind" or the behavioristic "contingency-shaped behaviors". Elements of behaviorism and cognitive psychology were synthesized to form the basis of cognitive behavioral therapy, a form of psychotherapy modified from techniques developed by American psychologist Albert Ellis
Albert Ellis
Albert Ellis was an American psychologist who in 1955 developed rational emotive behavior therapy. He held M.A. and Ph.D. degrees in clinical psychology from Columbia University and founded and was the president and president emeritus of the New York City-based Albert Ellis Institute...

 and American psychiatrist Aaron T. Beck
Aaron T. Beck
Aaron Temkin Beck is an American psychiatrist and a professor emeritus in the department of psychiatry at the University of Pennsylvania. Beck's background was in psychoanalytic psychiatry...

. Cognitive psychology was subsumed along with other disciplines, such as philosophy of mind
Philosophy of mind
Philosophy of mind is a branch of modern analytic philosophy that studies the nature of the mind, mental events, mental functions, mental properties, consciousness and their relationship to the physical body, particularly the brain. The mind-body problem, i.e...

, computer science, and neuroscience
Neuroscience
Neuroscience is the scientific study of the nervous system. Such studies span the structure, function, evolutionary history, development, genetics, biochemistry, physiology, pharmacology, informatics, computational neuroscience and pathology of the nervous system.The International Brain Research...

, under the umbrella discipline of cognitive science
Cognitive science
Cognitive science can be defined as the study of mind or the study of thought. It embraces multiple research disciplines, including psychology, artificial intelligence, philosophy, neuroscience, linguistics, anthropology, sociology and biology. It relies on varying scientific methodology Cognitive...

.

Schools of thought



Various schools of thought have argued for a particular model to be used as a guiding theory by which all, or the majority, of human behavior can be explained. The popularity of these has waxed and waned over time. Some psychologists may think of themselves as adherents to a particular school of thought and reject the others, although most consider each as an approach to understanding the mind, and not necessarily as mutually exclusive theories. On the basis of Tinbergen's four questions
Tinbergen's four questions
When asked questions of animal and human behavior such as why these creatures see, even elementary school children can answer that vision helps them find food and avoid danger. Biologists have three additional explanations: A particular series of evolutionary steps are the cause of sight, the...

 a framework of reference of all fields of psychological research can be established (including anthropological research and humanities).

In modern times, psychology has adopted an integrated perspective towards understanding consciousness, behavior, and social interaction. This perspective is commonly referred to as the biopsychosocial approach. The basic tenet of the biopsychosocial model is that any given behavior or mental process affects and is affected by dynamically interrelated biological, psychological, and social factors.
The psychological aspect refers to the role that cognition and emotions play in any given psychological phenomenon—for example, the effect of mood or beliefs and expectations on an individual's reactions to an event. The biological aspect refers to the role of biological factors in psychological phenomena—for example, the effect of the prenatal environment on brain development and cognitive abilities, or the influence of genes on individual dispositions. The socio-cultural aspect refers to the role that social and cultural environments play in a given psychological phenomenon—for example, the role of parental or peer influence in the behaviors or characteristics of an individual.

Subfields


Psychology encompasses a vast domain, and includes many different approaches to the study of mental processes and behavior. Below are the major areas of inquiry that comprise psychology. A comprehensive list of the sub-fields and areas within psychology can be found at the list of psychology topics and list of psychology disciplines.

Abnormal



Abnormal psychology
Abnormal psychology
Abnormal psychology is an academic and applied subfield of psychology involving the scientific study of abnormal experience and behavior or with certain incompletely understood states in order to understand and change abnormal patterns of functioning.The definition of what constitutes 'abnormal'...

 is the study of abnormal behavior
Abnormality (behavior)
Abnormality, in the sense of something deviating from the normal or differing from the typical , is a subjectively defined behavioral characteristic, assigned to those with rare or dysfunctional conditions...

 in order to describe, predict, explain, and change abnormal patterns of functioning. Abnormal psychology studies the nature of psychopathology
Psychopathology
Psychopathology is a term which refers to either the study of mental illness or mental distress, or the manifestation of behaviors and experiences which may be indicative of mental illness or psychological impairment, such as abnormal, maladaptive behavior or mental activity.Psychopathology is that...

 and its causes, and this knowledge is applied in clinical psychology
Clinical psychology
Clinical psychology includes the scientific study and application of psychology for the purpose of understanding, preventing, and relieving psychologically-based distress or dysfunction and to promote subjective well-being and personal development...

 to treat patients with psychological disorders.

It can be difficult to draw the line between normal and abnormal behaviors. In general, abnormal behaviors must be maladaptive and cause an individual significant discomfort in order to be of clinical and research interest. According to the DSM-IV-TR, behaviors may be considered abnormal if they are associated with disability, personal distress, the violation of social norms, or dysfunction.

Biological



Biological psychology is the scientific study of the biological substrates of behavior and mental states. Seeing all behavior as intertwined with the nervous system
Nervous system
The nervous system is a network of specialized cells that communicate information about an organism's surroundings and itself. It processes this information and causes reactions in other parts of the body. It is composed of neurons and other specialized cells called glial cells that aid in the...

, biological psychologists feel it is sensible to study how the brain
Brain
The brain is the center of the nervous system in all vertebrate, and most invertebrate, animals. Some primitive animals such as jellyfish and starfish have a decentralized nervous system without a brain, while sponges lack any nervous system at all...

 functions in order to understand behavior. This is the approach taken in behavioral neuroscience
Behavioral neuroscience
Behavioral neuroscience, also known as biological psychology, biopsychology, or psychobiology is the application of the principles of biology, in particular neurobiology, to the study of mental processes and behavior in human and non-human animals...

, cognitive neuroscience
Cognitive neuroscience
Cognitive neuroscience is an academic field concerned with the scientific study of biological substrates underlying cognition, with a specific focus on the neural substrates of mental processes. It addresses the questions of how psychological/cognitive functions are produced by the brain...

, and neuropsychology
Neuropsychology
Neuropsychology is the basic scientific discipline that studies the structure and function of the brain related to specific psychological processes and overt behaviors. The term neuropsychology has been applied to lesion studies in humans and animals...

. Neuropsychology is the branch of psychology that aims to understand how the structure and function of the brain relate to specific behavioral and psychological processes. Neuropsychology is particularly concerned with the understanding of brain injury in an attempt to work out normal psychological function. The approach of cognitive neuroscience to studying the link between brain and behavior is to use neuroimaging tools, such as to observe which areas of the brain are active during a particular task.

Clinical



Clinical psychology
Clinical psychology
Clinical psychology includes the scientific study and application of psychology for the purpose of understanding, preventing, and relieving psychologically-based distress or dysfunction and to promote subjective well-being and personal development...

 includes the study and application of psychology for the purpose of understanding, preventing, and relieving psychologically-based distress or dysfunction
Mental illness
A mental disorder or mental illness is a psychological or behavioral pattern that occurs in an individual and is thought to cause distress or disability that is not expected as part of normal development or culture. The recognition and understanding of mental disorders has changed over time and...

 and to promote subjective well-being
Mental health
Mental health is a term used to describe either a level of cognitive or emotional well-being or an absence of a mental disorder. From perspectives of the discipline of positive psychology or holism mental health may include an individual's ability to enjoy life and procure a balance between life...

 and personal development. Central to its practice are psychological assessment and psychotherapy
Psychotherapy
Psychotherapy or personal counseling with a psychotherapist, is an intentional interpersonal relationship used by trained psychotherapists to aid a client or patient in problems of living.It aims to increase the individual's sense of their own well-being...

, although clinical psychologists may also engage in research, teaching, consultation, forensic testimony, and program development and administration.
Some clinical psychologists may focus on the clinical management of patients with brain injury
Brain damage
Brain damage, or acquired brain injury, is the destruction or degeneration of brain cells.-Causes:Brain damage may occur due to a wide range of conditions, illnesses, injuries, and as a result of iatrogenesis...

—this area is known as clinical neuropsychology
Clinical neuropsychology
Clinical neuropsychology is a sub-specialty of clinical psychology that specializes in the diagnostic assessment and treatment of patients with brain injury or neurocognitive deficits....

. In many countries clinical psychology is a regulated mental health profession
Mental health professional
A mental health professional is a person who offers services for the purpose of improving an individual's mental health or to treat mental illness. This broad category includes psychiatrists, clinical psychologists, clinical social workers, psychiatric nurses, mental health counselors as well as...

.

The work performed by clinical psychologists tends to be influenced by various therapeutic approaches, all of which involve a formal relationship between professional and client (usually an individual, couple, family, or small group). The various therapeutic approaches and practices are associated with different theoretical perspectives and employ different procedures intended to form a therapeutic alliance, explore the nature of psychological problems, and encourage new ways of thinking, feeling, or behaving. Four major theoretical perspectives are Psychodynamic
Psychodynamic psychotherapy
Psychodynamic psychotherapy is a form of depth psychology, the primary focus of which is to reveal the unconscious content of a client's psyche in an effort to alleviate psychic tension. In this way, it is similar to psychoanalysis, but psychodynamic therapy tends to be briefer and less...

, Cognitive Behavioral, Existential-Humanistic
Humanistic psychology
Humanistic psychology is a school of psychology that emerged in the 1950s in reaction to both behaviorism and psychoanalysis. It is explicitly concerned with the human dimension of psychology and the human context for the development of psychological theory....

, and Systems or Family therapy
Family therapy
Family therapy, also referred to as couple and family therapy and family systems therapy, is a branch of psychotherapy that works with families and couples in intimate relationships to nurture change and development. It tends to view change in terms of the systems of interaction between family...

. There has been a growing movement to integrate the various therapeutic approaches, especially with an increased understanding of issues regarding culture, gender, spirituality, and sexual-orientation. With the advent of more robust research findings regarding psychotherapy, there is evidence that most of the major therapies are about of equal effectiveness, with the key common element being a strong therapeutic alliance. Because of this, more training programs and psychologists are now adopting an eclectic therapeutic orientation
Integrative Psychotherapy
Integrative psychotherapy may involve the fusion of different schools of psychotherapy. The word 'integrative' in Integrative psychotherapy may also refer to integrating the personality and making it cohesive, and to the bringing together of the "affective, cognitive, behavioral, and physiological...

.

Cognitive


Cognitive psychology
Cognitive psychology
Cognitive psychology is a discipline within psychology that investigates the internal mental processes of thought such as visual processing, memory, problem solving, and language....

 studies cognition
Cognition
Cognition is the scientific term for "the process of thought". Usage of the term varies in different disciplines; for example in psychology and cognitive science, it usually refers to an information processing view of an individual's psychological functions...

, the mental processes
Mental function
Mental process, mental functions and cognitive processes are terms often used interchangeably to mean such functions or processes as perception, introspection, memory, creativity, imagination, conception, belief, reasoning, volition, and emotion...

 underlying mental activity. Perception
Perception
In philosophy, psychology, and the cognitive sciences, perception is the process of attaining awareness or understanding of sensory information. It is a task far more complex than was imagined in the 1950s and 1960s, when it was predicted that building perceiving machines would take about a decade,...

, learning
Learning
Learning is acquiring new knowledge, behaviors, skills, values, preferences or understanding, and may involve synthesizing different types of information. The ability to learn is possessed by humans, animals and some machines. Progress over time tends to follow learning curves.Human learning may...

, problem solving
Problem solving
Problem solving is a mental process and is part of the larger problem process that includes problem finding and problem shaping. Consideredthe most complex of all intellectual functions, problem solving has been defined as higher-order cognitive process that requires the modulation and control of...

, reasoning
Reasoning
Reasoning is the cognitive process of looking for reasons for beliefs, conclusions, actions or feelings.Humans have the ability to engage in reasoning about their own reasoning. Different forms of such reflection on reasoning occur in different fields...

, thinking, memory
Memory
In psychology, memory is an organism's mental ability to store, retain, and recall information. Traditional studies of memory began in the fields of philosophy, including techniques of artificially enhancing the memory....

, attention
Attention
Attention is the cognitive process of selectively concentrating on one aspect of the environment while ignoring other things. Attention has also been referred to as the allocation of processing resources...

, language
Language
A language is a system for encoding and decoding information. In its most common use, the term refers to so-called "natural languages" — the forms of communication considered peculiar to humankind. In linguistics the term is extended to refer to the human cognitive facility of creating and using...

 and emotion
Emotion
An emotion is a mental and physiological state associated with a wide variety of feelings, thoughts, and behavior. Emotions are subjective experiences, often associated with mood, temperament, personality, and disposition. The English word 'emotion' is derived from the French word émouvoir...

 are areas of research. Classical cognitive psychology is associated with a school of thought known as cognitivism
Cognitivism (psychology)
In psychology, cognitivism is a theoretical approach in understanding the mind using quantitative, positivist and scientific methods, that describes mental functions as information processing models.-Theoretical approach:...

, whose adherents argue for an information processing
Information processing
Information processing is the change of information in any manner detectable by an observer. As such, it is a process which describes everything which happens in the universe, from the falling of a rock to the printing of a text file from a digital computer system...

 model of mental function, informed by functionalism
Functionalism (philosophy of mind)
Functionalism is a theory of the mind in contemporary philosophy, developed largely as an alternative to both the identity theory of mind and behaviourism. Its core idea is that mental states are constituted solely by their functional role — that is, they are causal relations to other mental...

 and experimental psychology
Experimental psychology
Experimental psychology is a methodological approach rather than a subject and encompasses varied fields within psychology. Experimental psychologists have traditionally conducted research, published articles, and taught classes on neuroscience, developmental psychology, sensation, perception,...

.

On a broader level, cognitive science
Cognitive science
Cognitive science can be defined as the study of mind or the study of thought. It embraces multiple research disciplines, including psychology, artificial intelligence, philosophy, neuroscience, linguistics, anthropology, sociology and biology. It relies on varying scientific methodology Cognitive...

 is an interdisciplinary enterprise of cognitive psychologists
Cognitive psychology
Cognitive psychology is a discipline within psychology that investigates the internal mental processes of thought such as visual processing, memory, problem solving, and language....

, cognitive neuroscientists
Cognitive neuroscience
Cognitive neuroscience is an academic field concerned with the scientific study of biological substrates underlying cognition, with a specific focus on the neural substrates of mental processes. It addresses the questions of how psychological/cognitive functions are produced by the brain...

, researchers in artificial intelligence
Artificial intelligence
Artificial intelligence is the intelligence of machines and the branch of computer science which aims to create it. Textbooks define the field as "the study and design of intelligent agents,"...

, linguists
Linguistics
Linguistics is the scientific study of natural language. Linguistics encompasses a number of sub-fields. An important topical division is between the study of language structure and the study of meaning...

, human–computer interaction
Human–computer interaction
Human–computer interaction is the study of interaction between people and computers. It is often regarded as the intersection of computer science, behavioral sciences, design and several other fields of study...

, computational neuroscience
Computational neuroscience
Computational neuroscience is the study of brain function in terms of the information processing properties of the structures that make up the nervous system...

, logicians
Mathematical logic
Mathematical logic is a subfield of mathematics with close connections to computer science and philosophical logic. The field includes both the mathematical study of logic and the applications of formal logic to other areas of mathematics...

 and social scientists
Anthropology
Anthropology is the study of human beings, everywhere and throughout time....

. Computational models
Computer simulation
A computer simulation, a computer model, or a computational model is a computer program, or network of computers, that attempts to simulate an abstract model of a particular system...

 are sometimes used to simulate phenomena of interest. Computational models provide a tool for studying the functional organization of the mind whereas neuroscience provides measures of brain activity.

Community


Community psychology deals with the relationships of the individual to communities and the wider society. Community psychologists seek to understand the quality of life of individuals, communities, and society. Their aim is to enhance quality of life through collaborative research and action.[1].

Community Psychology makes use of various perspectives within and outside of Psychology to address issues of communities, the relationships within them, and people's attitudes about them. Through collaborative research and action, community psychologists (practitioners and researchers) seek to understand and to enhance quality of life for individuals, communities, and society. Community psychology takes a public health approach and focuses on prevention and early intervention as a means to solve problems in addition to treatment. Rappaport (1977) discusses the perspective of community psychology as an ecological perspective with the person-environment fit being the focus of study and action instead of attempting to change the person or the environment when an individual is seen as having a problem.[2]

Comparative


Comparative psychology
Comparative psychology
Comparative psychology usually refers to the study of the behavior and mental life of animals other than human beings. However, psychologists and scientists do not always agree on this definition. Comparative psychology has also been described as branch of psychology in which emphasis is placed on...

 refers to the study of the behavior and mental life of animal
Animal
Animals are a major group of mostly multicellular, eukaryotic organisms of the kingdom Animalia or Metazoa. Their body plan eventually becomes fixed as they develop, although some undergo a process of metamorphosis later on in their life. Most animals are motile, meaning they can move spontaneously...

s other than human beings. It is related to disciplines outside of psychology that study animal behavior such as ethology
Ethology
Ethology is the scientific study of animal behavior, and a sub-topic of zoology....

. Although the field of psychology is primarily concerned with humans the behavior and mental processes of animal
Animal
Animals are a major group of mostly multicellular, eukaryotic organisms of the kingdom Animalia or Metazoa. Their body plan eventually becomes fixed as they develop, although some undergo a process of metamorphosis later on in their life. Most animals are motile, meaning they can move spontaneously...

s is also an important part of psychological research. This being either as a subject in its own right (e.g., animal cognition
Animal cognition
Animal cognition is the title given to a modern approach to the mental capacities of non-human animals. It has developed out of comparative psychology, but has also been strongly influenced by the approach of ethology, behavioral ecology, and evolutionary psychology...

 and ethology) or with strong emphasis about evolutionary links, and somewhat more controversially, as a way of gaining an insight into human psychology. This is achieved by means of comparison or via animal models of emotional and behavior systems as seen in neuroscience of psychology (e.g., affective neuroscience
Affective neuroscience
Affective neuroscience is the study of the neural mechanisms of emotion. This interdisciplinary field combines neuroscience with the psychological study of personality, emotion, and mood.-Brain areas related to emotion:...

 and social neuroscience
Social neuroscience
Social neuroscience is an interdisciplinary field devoted to understanding how biological systems implement social processes and behavior, and to using biological concepts and methods to inform and refine theories of social processes and behavior....

).

Counseling



Counseling psychology
Counseling psychology
Counseling psychology is a psychological specialty that encompasses research and applied work in several broad domains: counseling process and outcome; supervision and training; career development and counseling; diversity and multiculturalism; and prevention and health...

 seeks to facilitate personal and interpersonal
Interpersonal relationship
An interpersonal relationship is an association between two or more people that may range from fleeting to enduring. This association may be based on limerence, love and liking, regular business interactions, or some other type of social commitment...

 functioning across the lifespan with a focus on emotional, social, vocational
Vocational education
Vocational education or Vocational Education and Training , also called Career and Technical Education , prepares learners for jobs that are based in manual or practical activities, traditionally non-academic and totally related to a specific trade, occupation or vocation, hence the term, in which...

, educational, health-related, developmental, and organizational concerns. Counselors are primarily clinicians, using psychotherapy and other interventions in order to treat clients. Traditionally, counseling psychology has focused more on normal developmental issues and everyday stress
Stress (medicine)
Stress is a biological term for the consequences of the failure of a human or animal to respond appropriately to emotional or physical threats to the organism, whether actual or imagined....

 rather than psychopathology, but this distinction has softened over time. Counseling psychologists are employed in a variety of settings, including universities, hospitals, schools, governmental organizations, businesses, private practice, and community mental health centers.

Critical



Critical psychology
Critical psychology
Critical psychology is a branch of psychology that is aimed at critiquing mainstream psychology and attempts to apply psychology in more progressive ways, often looking towards social change as a means of preventing and treating psychopathology...

 applies the methodology of critical theory
Critical theory
Critical theory is the examination and critique of society and culture, drawing from knowledge across the social sciences and humanities. The term has two quite different meanings with different origins and histories, one originating in social theory and the other in literary criticism...

 to psychology. Accordingly, it seeks to identify the supportive roles that psychology and psychologists play, often unwittingly, in oppressive ideologies
Ideology
An ideology is a set of aims and ideas that directs one's goals, expectations, and actions. An ideology can be thought of as a comprehensive vision, as a way of looking at things , as in common sense and several philosophical tendencies , or a set of ideas proposed by the dominant class of a...

, and it strives to replace these roles with ones that can transform oppressive social structure
Social structure
Social structure is a term used in sociology and anthropology to refer to relationships or bonds between groups of individuals . Whereas 'structure' refers to "the macro", "agency" refers to "the micro"...

s. Critical psychology operates on the belief "that mainstream psychology has institutionalized a narrow view of the field’s ethical mandate to promote human welfare", and critical psychology endeavors to broaden the view of that mandate.

A critical psychologist might ask whether a case of "work stress" warrants efforts to change the macro-level
Macrosociology
Macrosociology is a sociological approach that analyzes societies, social systems or populations on a large scale or at a high level of abstraction. It is considered one of the main foundations of sociology, alongside microsociology and mesosociology. Microsociology focuses on the individual...

 systems that control the work, rather than to treat in isolation those individuals who experience the stress. One might also ask why "mainstream trauma efforts fail to incorporate a focus on human rights and social justice" in war-ravaged communities. In short, critical psychology seeks, where it deems appropriate, to raise psychology's level of analysis from the individual to society, and to render psychology more foundationally transformative than superficially ameliorative. Critical psychology has been applied to a wide array of psychology's other subfields, and many of its theorists are employed in mainstream psychological professions.

Developmental


Mainly focusing on the development of the human mind through the life span, developmental psychology
Developmental psychology
Developmental psychology, also known as human development, is the scientific study of systematic psychological changes that occur in human beings over the course of the life span. Originally concerned with infants and children, the field has expanded to include adolescence and adult development,...

 seeks to understand how people come to perceive, understand, and act within the world and how these processes change as they age. This may focus on intellectual, cognitive, neural, social, or moral development. Researchers who study children use a number of unique research methods to make observations in natural settings or to engage them in experimental tasks. Such tasks often resemble specially designed games and activities that are both enjoyable for the child and scientifically useful, and researchers have even devised clever methods to study the mental processes of small infants. In addition to studying children, developmental psychologists also study aging and processes throughout the life span, especially at other times of rapid change (such as adolescence and old age). Developmental psychologists draw on the full range of theorists in scientific psychology to inform their research.

Educational



Educational psychology
Educational psychology
Educational psychology is the study of how humans learn in educational settings, the effectiveness of educational interventions, the psychology of teaching, and the social psychology of schools as organizations. Educational psychology is concerned with how students learn and develop, often focusing...

 is the study of how humans learn in education
Education
Education in its broadest sense is any act or experience that has a formative effect on the mind, character or physical ability of an individual...

al settings, the effectiveness of educational interventions, the psychology of teaching, and the social psychology
Social psychology (psychology)
Social psychology is the scientific study of how people's thoughts, feelings, and behaviors are influenced by the actual, imagined, or implied presence of others. By this definition, scientific refers to the empirical method of investigation. The terms thoughts, feelings, and behaviors include all...

 of school
School
A school , is an institution designed to allow and encourage students to learn, under the supervision of teachers. Most countries have systems of formal education, which is commonly compulsory. In these systems, students progress through a series of schools...

s as organizations. The work of child psychologists such as Lev Vygotsky
Lev Vygotsky
Lev Semyonovich Vygotsky was a Soviet psychologist and the founder of cultural-historical psychology.- Biography :...

, Jean Piaget
Jean Piaget
Jean Piaget was a Swiss psychologist and philosopher, well known for his pedagogical studies...

 and Jerome Bruner
Jerome Bruner
Jerome Seymour Bruner is an American psychologist who has contributed to cognitive psychology and cognitive learning theory in educational psychology, as well as to history and to the general philosophy of education. Bruner is currently a senior research fellow at the New York University School...

 has been influential in creating teaching methods and educational practices. Educational psychology is often included in teacher education programs, at least in North America, Australia, and New Zealand.

Evolutionary



Evolutionary psychology
Evolutionary psychology
Evolutionary psychology attempts to explain psychological traits—such as memory, perception, or language—as adaptations, that is, as the functional products of natural selection or sexual selection. Adaptationist thinking about physiological mechanisms, such as the heart, lungs, and immune system,...

 explores the gene
Gene
A gene is the basic unit of heredity in a living organism. All living things depend on genes. Genes hold the information to build and maintain their cells and pass genetic traits to offspring...

tic roots of mental and behavioral patterns, and posits that common patterns may have emerged because they were highly adaptive
Adaptation
Adaptation is the process whereby a population becomes better suited to its habitat. This process takes place over many generations, and is one of the basic phenomena of biology....

 for humans in the environments of their evolutionary past—even if some of these patterns are maladaptive in today's environments. Fields closely related to evolutionary psychology are animal behavioral ecology
Behavioral ecology
Behavioral ecology is the study of the ecological and evolutionary basis for animal behavior, and the roles of behavior in enabling an animal to adapt to its environment...

, human behavioral ecology
Human behavioral ecology
Human behavioral ecology or human evolutionary ecology applies the principles of evolutionary theory and optimization to the study of human behavioral and cultural diversity. HBE examines the adaptive design of traits, behaviors, and life histories of humans in an ecological context. HBE overlaps...

, dual inheritance theory
Dual inheritance theory
Dual Inheritance Theory , also known as Gene-Culture Coevolution, was developed in the late 1970s and early 1980s to explain how human behavior is a product of two different and interacting evolutionary processes: genetic evolution and cultural evolution...

, and sociobiology
Sociobiology
Sociobiology is a synthesis of scientific disciplines which attempts to explain social behavior in animal species by considering the Darwinian advantages specific behaviors may have. It is often considered a branch of biology and sociology, but also draws from ethology, anthropology, evolution,...

. Memetics
Memetics
Memetics is a term coined by Douglas Hofstadter in the 1980s, relating to the notion of meme, introduced by Richard Dawkins, as genetics relates to that of gene....

, founded by Richard Dawkins
Richard Dawkins
Clinton Richard Dawkins, FRS, FRSL is a British ethologist, zoologist, Neo-Darwinian evolutionary biologist and theorist and a popular science author....

, is a related but competing field that proposes that cultural evolution
Sociocultural evolution
Sociocultural evolution is an umbrella term for theories of cultural evolution and social evolution, describing how cultures and societies have developed over time...

 can occur in a Darwinian
Charles Darwin
Charles Robert Darwin FRS was an English naturalist who realised and presented compelling evidence that all species of life have evolved over time from common ancestors, through the process he called natural selection...

 sense but independently of Mendelian
Gregor Mendel
Gregor Johann Mendel was an Augustinian priest and scientist, and is often called the father of genetics for his study of the inheritance of certain traits in pea plants. Mendel showed that the inheritance of these traits follows particular laws, which were later named after him...

 mechanisms; it therefore examines the ways in which thoughts, or meme
Meme
A meme is a postulated unit or element of cultural ideas, symbols or practices, and is transmitted from one mind to another through speech, gestures, rituals, or other imitable phenomena...

s, may evolve independently of genes.

Forensic



Forensic psychology
Forensic psychology
Forensic psychology is the intersection between psychology and the criminal justice system. It involves understanding criminal law in the relevant jurisdictions in order to be able to interact appropriately with judges, attorneys and other legal professionals...

 applies psychology to legal case
Legal case
A legal case is a dispute between opposing parties resolved by a court, or by some equivalent legal process. A legal case may be either civil or criminal...

s, covering a broad range of practices including the clinical evaluations
Competency evaluation (law)
In the United States criminal justice system, a competency evaluation is an assessment of the ability of a defendant ability to understand and rationally participate in a court process....

 of defendant
Defendant
A defendant or defender is any party who is required to answer the complaint of a plaintiff or pursuer in a civil lawsuit before a court, or any party who has been formally charged or accused of violating a criminal statute....

s, reports to judges and attorneys, and courtroom testimony on given issues. Forensic psychologists are appointed by the court or hired by attorneys to conduct competency to stand trial evaluations, competency to be executed evaluations, sanity evaluations, involuntary commitment evaluations, provide sentencing recommendations, and sex offender evaluation and treatment evaluations and provide recommendations to the court through written reports and testimony. Many of the questions the court asks the forensic psychologist go ultimately to legal issues
Ultimate issue (law)
An ultimate issue in criminal law is a legal issue at stake in the prosecution of a crime for which an expert witness is providing testimony.-Example:...

, although a psychologist cannot answer legal questions. For example, there is no definition of sanity in psychology. Rather, sanity is a legal definition that varies from place to place throughout the world. Therefore, a prime qualification of a forensic psychologist is an intimate understanding of the law, especially criminal law.

Global



Global psychology
Global psychology
Global psychology is a subfield of psychology that addresses the issues raised in the global sustainability debate. Global psychologists advocate the pursuit of sustainable values and of meaning exceeding both self-realization and religious faith. Mainstream psychology, they allege, lacks the wide...

 is a subfield of psychology that addresses the issues raised in the global sustainability
Sustainability
Sustainability, in a broad sense, is the capacity to endure. In ecology, the word describes how biological systems remain diverse and productive over time...

 debate. Like critical psychology, global psychology expands the objective of psychology to macro-level trends; it examines the overwhelming consequences of global warming
Global warming
Global warming is the increase in the average temperature of the Earth's near-surface air and oceans since the mid-20th century and its projected continuation. Global surface temperature increased 0.74 ± 0.18 °C during the last century...

, economic destabilization and other large-scale phenomena, while recognizing that global sustainability can best be achieved by psychologically sound individuals and cultures. Global psychologists advocate a simple and sensible, yet comprehensive, psychology, whose strength is its focus on the long-term well-being of all of humanity.

Health



Health psychology
Health psychology
Health psychology is concerned with understanding how biology, behavior, and social context influence health and illness. Health psychologists work alongside other medical professionals in clinical settings, work on behaviour change in public health promotion, teach at universities, and conduct...

 is the application of psychological theory and research to health, illness and health care. Whereas clinical psychology focuses on mental health and neurological illness, health psychology
Health psychology
Health psychology is concerned with understanding how biology, behavior, and social context influence health and illness. Health psychologists work alongside other medical professionals in clinical settings, work on behaviour change in public health promotion, teach at universities, and conduct...

 is concerned with the psychology of a much wider range of health-related behavior including healthy eating, the doctor-patient relationship, a patient's understanding of health information, and beliefs about illness. Health psychologists may be involved in public health campaigns, examining the impact of illness or health policy on quality of life
Quality of life
The term quality of life is used to evaluate the general well-being of individuals and societies. The term is used in a wide range of contexts, including the fields of international development, healthcare, and political science. Quality of life should not be confused with the concept of...

 and in research into the psychological impact of health and social care.

Industrial/organizational



Industrial and organizational psychology
Industrial and organizational psychology
Industrial and Organizational Psychology applies psychology to organizations and the workplace...

 (I/O) applies psychological concepts and methods to optimize human potential in the workplace. Personnel psychology, a subfield of I/O psychology, applies the methods and principles of psychology in selecting and evaluating workers. I/O psychology's other subfield, organizational psychology, examines the effects of work environments and management styles on worker motivation, job satisfaction, and productivity.

Legal


Legal psychology
Legal psychology
Legal psychology involves empirical, psychological research of the law, legal institutions, and people who come into contact with the law. Legal psychologists typically take basic social and cognitive theories and principles and apply them to issues in the legal system such as eyewitness memory,...

 is a research-oriented field populated with researchers from several different areas within psychology (although social
Social psychology (psychology)
Social psychology is the scientific study of how people's thoughts, feelings, and behaviors are influenced by the actual, imagined, or implied presence of others. By this definition, scientific refers to the empirical method of investigation. The terms thoughts, feelings, and behaviors include all...

 and cognitive
Cognitive psychology
Cognitive psychology is a discipline within psychology that investigates the internal mental processes of thought such as visual processing, memory, problem solving, and language....

 psychologists are typical). Legal psychologists explore such topics as jury decision-making, eyewitness memory, scientific evidence, and legal policy. The term "legal psychology" has only recently come into use, and typically refers to any non-clinical law-related research.

Occupational health


Occupational health psychology
Occupational health psychology
Occupational health psychology is concerned with the psychosocial characteristics of workplaces that contribute to the development of health-related problems in people who work. OHP is concerned about equally with problems of physical and mental health...

 (OHP) is a discipline that emerged out of health psychology
Health psychology
Health psychology is concerned with understanding how biology, behavior, and social context influence health and illness. Health psychologists work alongside other medical professionals in clinical settings, work on behaviour change in public health promotion, teach at universities, and conduct...

, industrial/organizational psychology
Industrial and organizational psychology
Industrial and Organizational Psychology applies psychology to organizations and the workplace...

, and occupational health
Occupational safety and health
Occupational safety and health is a cross-disciplinary area concerned with protecting the safety, health and welfare of people engaged in work or employment. The goal of all occupational safety and health programs is to foster a safe work environment...

. OHP is concerned with identifying psychosocial characteristics of workplaces that give rise to problems in physical (e.g., cardiovascular disease
Cardiovascular disease
Cardiovascular disease or cardiovascular diseases is the class of diseases that involve the heart or blood vessels ....

) and mental health (e.g., depression
Depression (mood)
In psychology and psychiatry, depression is a state of low mood and aversion to activity. While most often described as a disease or dysfunction, there are also strong arguments for seeing depression as an adaptive defense mechanism....

). OHP has investigated such psychosocial characteristics of workplaces as workers' decision latitude and supervisors' supportiveness. OHP also concerns itself with interventions that can prevent or ameliorate work-related health problems. Such interventions have important, beneficial implications for the economic success of organizations. Other research areas of concern to OHP include workplace violence, unemployment, and workplace safety. Two exemplary OHP journals are the Journal of Occupational Health Psychology
Journal of Occupational Health Psychology
The Journal of Occupational Health Psychology is a peer-reviewed, English language journal published four times per year by the American Psychological Association...

and Work & Stress
Work & Stress
Work & Stress is a peer-reviewed scientific journal published four times per year by the European Academy of Occupational Health Psychology . Work & Stress has become an important outlet for a broad range of research in occupational health psychology...

. Two prominent OHP professional organizations include the European Academy of Occupational Health Psychology
European Academy of Occupational Health Psychology
The European Academy of Occupational Health Psychology , a pan-European organization, was established in 1999. It is the first organization of its kind in the world that is devoted to occupational health psychology ....

 and the Society for Occupational Health Psychology
Society for Occupational Health Psychology
The focal interest of the Society for Occupational Health Psychology is the “generation, dissemination, and application of scientific knowledge in order to improve worker health and well-being.” The goals of the Society are threefold. First, SOHP promotes psychological research on important...

.

Personality


Personality psychology
Personality psychology
Personality psychology is a branch of psychology that studies personality and individual differences.Its areas of focus include:* Constructing a coherent picture of a person and his or her major psychological processes...

 studies enduring patterns of behavior
Behavior
Behavior or behaviour refers to the actions or reactions of an object or organism, usually in relation to the environment. Behavior can be conscious or subconscious, overt or covert, and voluntary or involuntary....

, thought
Thought
Thought and thinking are mental forms and processes, respectively . Thinking allows beings to model the world and to deal with it according to their objectives, plans, ends and desires. Words referring to similar concepts and processes include cognition, sentience, consciousness, idea, and...

, and emotion
Emotion
An emotion is a mental and physiological state associated with a wide variety of feelings, thoughts, and behavior. Emotions are subjective experiences, often associated with mood, temperament, personality, and disposition. The English word 'emotion' is derived from the French word émouvoir...

 in individuals, commonly referred to as personality. Theories of personality vary across different psychological schools and orientations. They carry different assumptions about such issues as the role of the unconscious
Unconscious mind
The unconscious mind is a term invented by the 18th century German romantic philosopher Ser Christopher Riegel and later introduced into English by the poet and essayist Samuel Taylor Coleridge...

 and the importance of childhood experience. According to Freud, personality is based on the dynamic interactions of the ego, superego, and id. Trait theorists
Trait theory
In psychology, Trait theory is a major approach to the study of human personality. Trait theorists are primarily interested in the measurement of traits, which can be defined as habitual patterns of behavior, thought, and emotion. According to this perspective, traits are relatively stable over...

, in contrast, attempt to analyze personality in terms of a discrete number of key traits by the statistical method of factor analysis
Factor analysis
Factor analysis is a statistical method used to describe variability among observed variables in terms of fewer unobserved variables called factors. The observed variables are modeled as linear combinations of the factors, plus "error" terms. The information gained about the interdependencies can...

. The number of proposed traits has varied widely. An early model proposed by Hans Eysenck
Hans Eysenck
Hans Jürgen Eysenck was a British psychologist of German origin, best remembered for his work on intelligence and personality, though he worked in a wide range of areas...

 suggested that there are three traits that comprise human personality: extraversion-introversion
Extraversion and introversion
The trait of extroversion-introversion is a central dimension of human personality. Extroverts tend to be sociable, assertive, and interested in seeking out excitement. Introverts, in contrast, tend to be more reserved, less outgoing, but are also marked by a richer inner world...

, neuroticism
Neuroticism
Neuroticism is a fundamental personality trait in the study of psychology. It can be defined as an enduring tendency to experience negative emotional states. Individuals who score high on neuroticism are more likely than the average to experience such feelings as anxiety, anger, guilt, and clinical...

, and psychoticism
Psychoticism
Psychoticism is one of the three traits used by the psychologist Hans Eysenck in his P-E-N model model of personality....

. Raymond Cattell
Raymond Cattell
Raymond Bernard Cattell was a British and American psychologist known for his exploration of a wide variety of substantive areas in psychology...

 proposed a theory of 16 personality factors
16 Personality Factors
The 16 Personality Factors, measured by the 16PF Questionnaire, were multivariately-derived by psychologist Raymond Cattell.Below is a table outlining this model.- Raymond Cattell's 16 Personality Factors :...

. The "Big Five
Big Five personality traits
In contemporary psychology, the "Big Five" factors of personality are five broad domains or dimensions of personality which have been scientifically discovered to define human personality at the highest level of organization...

" or Five Factor Model, proposed by Lewis Goldberg
Lewis Goldberg
Lewis R. Goldberg is an American personality psychologist and a professor emeritus at the University of Oregon who is closely associated with the Big Five taxonomy of personality. He is the creator of the International Personality Item Pool , a website that provides public-domain personality...

 currently has strong support among trait theorists.


Quantitative


Quantitative psychology
Quantitative psychology
Research in quantitative psychology develops psychological theory in relation to mathematics and statistics. Psychological research requires the elaboration of existing methods and the development of new concepts, so that quantitative psychology requires more than "applications" of statistics and...

 involves the application of mathematical and statistical
Statistics
Statistics is a branch of mathematics concerned with collecting and interpreting data. According to other definitions, it is a mathematical science pertaining to the collection, analysis, interpretation or explanation, and presentation of data. Statisticians improve the quality of data with the...

 modeling in psychological research, and the development of statistical methods for analyzing and explaining behavioral data. The term "Quantitative psychology" is relatively new and little used (only recently have Ph.D. programs in quantitative psychology been formed), and it loosely covers the longer standing subfields psychometrics
Psychometrics
Psychometrics is the field of study concerned with the theory and technique of educational and psychological measurement, which includes the measurement of knowledge, abilities, attitudes, and personality traits. The field is primarily concerned with the study of measurement instruments such as...

 and mathematical psychology
Mathematical psychology
Mathematical psychology is an approach to psychological research that is based on mathematical modeling of perceptual, cognitive and motor processes, and on the establishment of law-like rules that relate quantifiable stimulus characteristics with quantifiable behavior...

.

Psychometrics
Psychometrics
Psychometrics is the field of study concerned with the theory and technique of educational and psychological measurement, which includes the measurement of knowledge, abilities, attitudes, and personality traits. The field is primarily concerned with the study of measurement instruments such as...

 is the field of psychology concerned with the theory and technique of psychological measurement
Measurement
In science, measurement is the process of obtaining the magnitude of a quantity, such as length or mass, relative to a unit of measurement, such as a meter or a kilogram...

, which includes the measurement of knowledge
Knowledge
Knowledge is defined by the Oxford English Dictionary as expertise, and skills acquired by a person through experience or education; the theoretical or practical understanding of a subject, what is known in a particular field or in total; facts and information or awareness or familiarity gained...

, abilities
Ability
Ability may be:* Aptitude* Intelligence* Skill* ExpertAbility may also refer to:* Ability score, in role-playing games* Ability Plus Software, makers of the office suite Ability Office* Ability grouping* ABILITY Magazine* Ability Magazine...

, attitudes
Attitude (psychology)
An attitude is a hypothetical construct that represents an individual's degree of like or dislike for an item. Attitudes are generally positive or negative views of a person, place, thing, or event-- this is often referred to as the attitude object...

, and personality traits. Measurement
Level of measurement
The "levels of measurement", or scales of measure are expressions that typically refer to the theory of scale types developed by the psychologist Stanley Smith Stevens. Stevens proposed his theory in a 1946 Science article titled "On the theory of scales of measurement"...

 of these phenomena
Phenomenon
A phenomenon is any observable occurrence. In popular usage, a phenomenon often refers to an extraordinary event. In scientific usage, a phenomenon is any event that is observable, however commonplace it might be, even if it requires the use of instrumentation to observe it...

 is difficult, and much research has been developed to define and analyze such phenomena. Psychometric research typically involves two major research tasks, namely: (i) the construction of instruments
Laboratory equipment
Laboratory equipment refers to the various tools and equipment used by scientists working in a laboratory. These include tools such as Bunsen burners, and microscopes as well as specialty equipment such as operant conditioning chambers, spectrophotometers and calorimeters...

 and procedures for measurement; and (ii) the development and refinement of theoretical approaches to measurement.

Mathematical psychology
Mathematical psychology
Mathematical psychology is an approach to psychological research that is based on mathematical modeling of perceptual, cognitive and motor processes, and on the establishment of law-like rules that relate quantifiable stimulus characteristics with quantifiable behavior...

 is the subdiscipline that is concerned with the development of psychological theory in relation with mathematics and statistics. Basic topics in mathematical psychology include measurement theory
Level of measurement
The "levels of measurement", or scales of measure are expressions that typically refer to the theory of scale types developed by the psychologist Stanley Smith Stevens. Stevens proposed his theory in a 1946 Science article titled "On the theory of scales of measurement"...

 and mathematical learning theory
Learning theory
Learning theory may refer to:* Learning theory , the process of how humans learn** Behaviorism** Cognitivism** Constructivism** Connectivism* Computational learning theory, a mathematical theory to analyze machine learning algorithms...

 as well as the modeling and analysis of mental
Mental function
Mental process, mental functions and cognitive processes are terms often used interchangeably to mean such functions or processes as perception, introspection, memory, creativity, imagination, conception, belief, reasoning, volition, and emotion...

 and motor processes
Motor system
The motor system is the part of the central nervous system that is involved to movement. It consists of the pyramidal and extrapyramidal system....

. Psychometrics
Psychometrics
Psychometrics is the field of study concerned with the theory and technique of educational and psychological measurement, which includes the measurement of knowledge, abilities, attitudes, and personality traits. The field is primarily concerned with the study of measurement instruments such as...

 is more associated with educational psychology, personality
Personality psychology
Personality psychology is a branch of psychology that studies personality and individual differences.Its areas of focus include:* Constructing a coherent picture of a person and his or her major psychological processes...

, and clinical psychology. Mathematical psychology
Mathematical psychology
Mathematical psychology is an approach to psychological research that is based on mathematical modeling of perceptual, cognitive and motor processes, and on the establishment of law-like rules that relate quantifiable stimulus characteristics with quantifiable behavior...

 is more closely related to psychonomics
Psychonomics
Psychonomics describes an approach to psychology that aims at discovering the laws that govern the workings of the mind . The field is directly related to experimental psychology. The word is used most prominently by the Psychonomic Society, a society of experimental psychologists in the United...

/experimental
Experimental psychology
Experimental psychology is a methodological approach rather than a subject and encompasses varied fields within psychology. Experimental psychologists have traditionally conducted research, published articles, and taught classes on neuroscience, developmental psychology, sensation, perception,...

 and cognitive
Cognitive psychology
Cognitive psychology is a discipline within psychology that investigates the internal mental processes of thought such as visual processing, memory, problem solving, and language....

, and physiological psychology
Physiological psychology
Physiological psychology is a subdivision of behavioral neuroscience or biological psychology that studies the neural mechanisms of perception and behavior through direct manipulation of the brains of nonhuman animal subjects in controlled experiments...

 and (cognitive
Cognitive neuroscience
Cognitive neuroscience is an academic field concerned with the scientific study of biological substrates underlying cognition, with a specific focus on the neural substrates of mental processes. It addresses the questions of how psychological/cognitive functions are produced by the brain...

) neuroscience
Neuroscience
Neuroscience is the scientific study of the nervous system. Such studies span the structure, function, evolutionary history, development, genetics, biochemistry, physiology, pharmacology, informatics, computational neuroscience and pathology of the nervous system.The International Brain Research...

.

Social



Social psychology
Social psychology (psychology)
Social psychology is the scientific study of how people's thoughts, feelings, and behaviors are influenced by the actual, imagined, or implied presence of others. By this definition, scientific refers to the empirical method of investigation. The terms thoughts, feelings, and behaviors include all...

 is the study of social behavior and mental processes, with an emphasis on how humans think about each other and how they relate to each other. Social psychologists are especially interested in how people react to social situations. They study such topics as the influence of others on an individual's behavior (e.g. conformity, persuasion
Persuasion
Persuasion is a form of social influence. It is the process of guiding people and oneself toward the adoption of an idea, attitude, or action by rational and symbolic means. It is a strategy of problem-solving relying on "appeals" rather than coercion...

), and the formation of beliefs, attitudes
Attitude (psychology)
An attitude is a hypothetical construct that represents an individual's degree of like or dislike for an item. Attitudes are generally positive or negative views of a person, place, thing, or event-- this is often referred to as the attitude object...

, and stereotype
Stereotype
A stereotype is a commonly held public belief about specific social groups, or types of individuals.The concepts of "stereotype" and "prejudice" are often confused with many other different meanings. Stereotypes are standardized and simplified conceptions of groups, based on some prior...

s about other people. Social cognition
Social cognition
Social cognition is the study of how people process social information, especially its encoding, storage, retrieval, and application to social situations. Social cognition’s focus on information processing has many affinities with its sister discipline, cognitive psychology...

 fuses elements of social and cognitive psychology in order to understand how people process, remember, and distort social information. The study of group dynamics
Group dynamics
Group dynamics is the study of groups, and also a general term for group processes. Relevant to the fields of psychology, sociology, and communication studies, a group is two or more individuals who are connected to each other by social relationships...

 reveals information about the nature and potential optimization of leadership, communication, and other phenomena that emerge at least at the microsocial
Microsociology
Microsociology is one of the main branches of sociology which concerns itself with the nature of everyday human social interactions on a small scale. It relates to agency and social action as components of the structure and agency debate...

 level. In recent years, many social psychologists have become increasingly interested in implicit
Implicit Association Test
The Implicit Association Test is an experimental method within social psychology designed to measure the strength of automatic association between mental representations of objects in memory...

 measures, mediational
Mediation (Statistics)
In statistics, a mediation model is one that seeks to identify and explicate the mechanism that underlies an observed relationship between an independent variable and a dependent variable via the inclusion of a third explanatory variable, known as a mediator variable...

 models, and the interaction of both person and social variables in accounting for behavior.

School



School psychology
School psychology
School psychology is a field that applies principles of clinical psychology and educational psychology to the diagnosis and treatment of children's and adolescents' behavioral and learning problems...

 combines principles from educational psychology
Educational psychology
Educational psychology is the study of how humans learn in educational settings, the effectiveness of educational interventions, the psychology of teaching, and the social psychology of schools as organizations. Educational psychology is concerned with how students learn and develop, often focusing...

 and clinical psychology
Clinical psychology
Clinical psychology includes the scientific study and application of psychology for the purpose of understanding, preventing, and relieving psychologically-based distress or dysfunction and to promote subjective well-being and personal development...

 to understand and treat students with learning disabilities; to foster the intellectual growth of "gifted" students; to facilitate prosocial behavior
Prosocial behavior
Prosocial behavior Is caring about the welfare and rights of others, feeling concern and empathy for them, and acting In a way that benefits others are all components of prosocial behavior..-Altruism and Reciprocity:...

s in adolescents; and otherwise to promote safe, supportive, and effective learning environments. School psychologists are trained in educational and behavioral assessment, intervention, prevention, and consultation, and many have extensive training in research. Currently, school psychology is the only field in which a professional can be called a "psychologist" without a doctoral degree, with the National Association of School Psychologists
National Association of School Psychologists
The National Association of School Psychologists is the major national professional organization for school psychologists in the United States...

 (NASP) recognizing the Specialist degree
Specialist degree
-The Specialist degree in the Commonwealth of Independent States:The specialist degree was also the only first degree in the former Soviet Union. In the early 1990s bakalavr and magistr degrees were introduced in all the countries of the Commonwealth of Independent States, except in Turkmenistan...

 as the entry level. This is a matter of controversy as the APA
American Psychological Association
The American Psychological Association is a professional organization representing psychologists in the U.S., with around 150,000 members and an annual budget of around $70m...

 does not recognize anything below a doctorate as the entry level for a psychologist. Specialist-level school psychologists, who typically receive three years of graduate training, function almost exclusively within school systems, while those at the doctoral-level are found in a number of other settings as well, including universities, hospitals, clinics, and private practice.

Research methods


Psychology tends to be eclectic
Eclecticism
Eclecticism is a conceptual approach that does not hold rigidly to a single paradigm or set of assumptions, but instead draws upon multiple theories, styles, or ideas to gain complementary insights into a subject, or applies different theories in particular cases.It can sometimes seem inelegant or...

, drawing on knowledge from other fields to help explain and understand psychological phenomena. Additionally, psychologists make extensive use of the three modes of inference that were identified by C. S. Peirce: Deduction
Deduction
Deduction: an argument or reasoning process in which the conclusion follows from the premises with logical necessity* Deductive reasoning, inference in which the conclusion is of no greater generality than the premises...

, induction
Inductive reasoning
Induction, also known as inductive reasoning or inductive logic, is a type of reasoning which involves moving from a set of specific facts to a general conclusion. It can also be seen as a form of theory-building, in which specific facts are used to create a theory that explains relationships...

, and abduction
Abduction
Abduction may refer to:-Abduction of a person or people:* Kidnapping, as a near synonym in criminal law, but sometimes used particularly in cases involving a woman or child** Bride kidnapping...

 (hypothesis generation). While often employing deductive-nomological
Deductive-nomological
The deductive-nomological model is a formalized view of scientific explanation in natural language. It characterizes scientific explanations primarily as deductive arguments with at least one natural law statement among its premises...

 reasoning, they also rely on inductive reasoning
Inductive reasoning
Induction, also known as inductive reasoning or inductive logic, is a type of reasoning which involves moving from a set of specific facts to a general conclusion. It can also be seen as a form of theory-building, in which specific facts are used to create a theory that explains relationships...

 to generate
Abduction
Abduction may refer to:-Abduction of a person or people:* Kidnapping, as a near synonym in criminal law, but sometimes used particularly in cases involving a woman or child** Bride kidnapping...

 explanation
Explanation
An explanation is a set of statements constructed to describe a set of facts which clarifies the causes, context, and consequencesof those facts....

s. For example, evolutionary psychologists
Evolutionary psychology
Evolutionary psychology attempts to explain psychological traits—such as memory, perception, or language—as adaptations, that is, as the functional products of natural selection or sexual selection. Adaptationist thinking about physiological mechanisms, such as the heart, lungs, and immune system,...

 propose explanations of human behavior in terms of such behaviors' advantages for hunter-gatherer
Hunter-gatherer
A hunter-gatherer society is one whose primary subsistence method involves the direct procurement of edible plants and animals from the wild, foraging and hunting without significant recourse to the domestication of either...

s.

Academic psychologists may focus purely on research
Basic research
Basic research or fundamental research is research carried out to increase understanding of fundamental principles. Many times the end results have no direct or immediate commercial benefits: basic research can be thought of as arising out of curiosity. However, in the long term it is the basis...

 and psychological theory, aiming to further psychological understanding in a particular area, while other psychologists may work in applied psychology
Applied psychology
The basic premise of applied psychology is the use of psychological principles and theories to overcome problems in other areas, such as mental health, business management, education, health, product design, ergonomics, and law...

 to deploy such knowledge for immediate and practical benefit. These approaches are not mutually exclusive, and many psychologists will be involved in both researching and applying psychology at some point during their career. Many clinical psychology programs aim to develop in practicing psychologists both knowledge of and experience with research and experimental methods, which they may interpret and employ as they treat individuals with psychological issues.

When an area of interest requires specific training and specialist knowledge, especially in applied areas, psychological associations normally establish a governing body to manage training requirements. Similarly, requirements may be laid down for university degrees in psychology, so that students acquire an adequate knowledge in a number of areas. Additionally, governing agencies in places where psychologists offer treatment to others may require that psychologists be licensed by government regulatory bodies.

Qualitative and quantitative research


Research in most areas of psychology is conducted in accord with the standards of the scientific method
Scientific method
Scientific method refers to a body of techniques for investigating phenomena, acquiring new knowledge, or correcting and integrating previous knowledge. To be termed scientific, a method of inquiry must be based on gathering observable, empirical and measurable evidence subject to specific...

. Psychological researchers seek the emergence of theoretically interesting categories and hypotheses from data, using qualitative
Qualitative research
Qualitative research is a field of inquiry applicable to many disciplines and subject matters. Qualitative researchers aim to gather an in-depth understanding of human behavior and the reasons that govern such behavior. The qualitative method investigates the why and how of decision making, not...

 or quantitative
Quantitative research
Quantitative research is the systematic scientific investigation of quantitative properties and phenomena and their relationships. The objective of quantitative research is to develop and employ mathematical models, theories and/or hypotheses pertaining to natural phenomena...

 methods (or both).

Qualitative psychological research
Qualitative psychological research
In psychology, qualitative research has come to be defined as research whose findings are not arrived at by statistical or other quantitative procedures. Qualitative research is often said to be naturalistic. That is, its goal is to understand behaviour in a natural setting...

 methods include interview
Interview
An interview is a conversation between two or more people where questions are asked by the interviewer to obtain information from the interviewee.- Employment-related :* Job interview* Case interview...

s, first-hand observation, and participant observation
Participant observation
Participant observation is a type of research strategy. It is a widely used methodology in many disciplines, particularly, cultural anthropology, but also sociology, communication studies, and social psychology...

. Qualitative researchers sometimes aim to enrich interpretations
Hermeneutics
Hermeneutics is the study of interpretation theory, and can be defined as either the art of interpretation, or the theory and practice of interpretation. Traditional hermeneutics - which includes Biblical hermeneutics - refers to the study of the interpretation of written texts, especially texts in...

 or critiques
Critical theory
Critical theory is the examination and critique of society and culture, drawing from knowledge across the social sciences and humanities. The term has two quite different meanings with different origins and histories, one originating in social theory and the other in literary criticism...

 of symbol
Symbol
A symbol is something such as an object, picture, written word, sound, or particular mark that represents something else by association, resemblance, or convention. For example, a red octagon may stand for "STOP". On maps, crossed sabres may indicate a battlefield...

s, subjective
Subject (philosophy)
In philosophy, a subject is a being which has subjective experiences, subjective consciousness or a relationship with another entity . A subject is an observer and an object is a thing observed...

 experiences, or social structure
Social structure
Social structure is a term used in sociology and anthropology to refer to relationships or bonds between groups of individuals . Whereas 'structure' refers to "the macro", "agency" refers to "the micro"...

s. Similar hermeneutic and critical aims have also been served by "quantitative methods", as in Erich Fromm
Erich Fromm
Erich Seligmann Fromm was an internationally renowned social psychologist, psychoanalyst, humanistic philosopher, and democratic socialist. He was associated with what became known as the Frankfurt School of critical theory.-Punanni:Erich Fromm was born on 23 March 1900, at Frankfurt am Main, the...

's study of Nazi voting
Authoritarian personality
The authoritarian personality is an influential theory of personality developed by University of California, Berkeley psychologists, Theodor W. Adorno, Else Frenkel-Brunswik, Daniel Levinson, and Nevitt Sanford in their 1950 book of the same name. The personality type is defined by nine traits that...

  or Stanley Milgram
Stanley Milgram
Stanley Milgram was an American social psychologist most notable for his controversial study known as the Milgram Experiment. The study was conducted in the 1960s during Milgram's professorship at Yale...

's studies of obedience to authority.

Quantitative psychological research
Quantitative psychological research
Quantitative psychological research is defined as psychological research which performs mathematical modeling and statistical estimation or statistical inference. This definition distinguishes it from so-called qualitative psychological research; however, many psychologists do not acknowledge any...

 lends itself to the statistical
Statistics
Statistics is a branch of mathematics concerned with collecting and interpreting data. According to other definitions, it is a mathematical science pertaining to the collection, analysis, interpretation or explanation, and presentation of data. Statisticians improve the quality of data with the...

 testing of hypotheses. Quantitatively oriented research designs include the experiment
Experiment
In scientific research, an experiment is a method of investigating causal relationships among variables, or to test a hypothesis. An experiment is a cornerstone of the empirical approach to acquiring data about the world and is used in both natural sciences and social sciences...

, quasi-experiment, cross-sectional study
Cross-sectional study
Cross-sectional studies form a class of research methods that involve observation of some subset of a population of items all at the same time, in which, groups can be compared at different ages with respect of independent variables, such as IQ and memory...

, case-control study, and longitudinal study
Longitudinal study
A longitudinal study is a correlational research study that involves repeated observations of the same items over long periods of time — often many decades. It is a type of observational study. Longitudinal studies are often used in psychology to study developmental trends across the life...

. The measurement and operationalization of important constructs is an essential part of these research designs. Statistical methods include the Pearson product-moment correlation coefficient
Pearson product-moment correlation coefficient
In statistics, the Pearson product-moment correlation coefficient is a measure of the correlation between two variables X and Y, giving a value between +1 and −1 inclusive. It is widely used in the sciences as a measure of the strength of linear dependence between two variables...

, the analysis of variance
Analysis of variance
In statistics, analysis of variance is a collection of statistical models, and their associated procedures, in which the observed variance is partitioned into components due to different explanatory variables...

, multiple linear regression, logistic regression
Logistic regression
In statistics, logistic regression is used for prediction of the probability of occurrence of an event by fitting data to a logistic curve. It is a generalized linear model used for binomial regression...

, structural equation modeling
Structural equation modeling
Structural equation modeling is a statistical technique for testing and estimating causal relationships using a combination of statistical data and qualitative causal assumptions...

, and hierarchical linear modeling
Hierarchical linear modeling
In statistics, hierarchical linear modeling , also known as multi-level analysis, is a more advanced form of simple linear regression and multiple linear regression. Multilevel analysis allows variance in outcome variables to be analysed at multiple hierarchical levels, whereas in simple linear...

.

Controlled experiments


Experimental psychological research is conducted in a laboratory under controlled conditions. This method of research relies on the application of the scientific method
Scientific method
Scientific method refers to a body of techniques for investigating phenomena, acquiring new knowledge, or correcting and integrating previous knowledge. To be termed scientific, a method of inquiry must be based on gathering observable, empirical and measurable evidence subject to specific...

 to understand behavior. Experimenters use several types of measurements, including rate of response, reaction time
Reaction time
Reaction time , is the elapsed time between the presentation of a sensory stimulus and the subsequent behavioral response. RT is often used in experimental psychology to measure the duration of mental operations, an area of research known as mental chronometry...

, and various psychometric
Psychometrics
Psychometrics is the field of study concerned with the theory and technique of educational and psychological measurement, which includes the measurement of knowledge, abilities, attitudes, and personality traits. The field is primarily concerned with the study of measurement instruments such as...

 measurements. Experiments are designed to test specific hypotheses
Hypothesis
A hypothesis is a proposed explanation for an observable phenomenon. The term derives from the Greek, ὑποτιθέναι - hypotithenai meaning "to put under" or "to suppose." For a hypothesis to be put forward as a scientific hypothesis, the scientific method requires that one can test it...

 (deductive approach) or evaluate functional relationships (inductive approach). They allow researchers to establish causal relationships between different aspects of behavior and the environment. In an experiment, one or more variables of interest are controlled by the experimenter (independent variable) and another variable is measured in response to different conditions (dependent variable). Experiments are one of the primary research methods in many areas of psychology, particularly cognitive
Cognitive psychology
Cognitive psychology is a discipline within psychology that investigates the internal mental processes of thought such as visual processing, memory, problem solving, and language....

/psychonomics
Psychonomics
Psychonomics describes an approach to psychology that aims at discovering the laws that govern the workings of the mind . The field is directly related to experimental psychology. The word is used most prominently by the Psychonomic Society, a society of experimental psychologists in the United...

, mathematical psychology
Mathematical psychology
Mathematical psychology is an approach to psychological research that is based on mathematical modeling of perceptual, cognitive and motor processes, and on the establishment of law-like rules that relate quantifiable stimulus characteristics with quantifiable behavior...

, psychophysiology
Psychophysiology
Psychophysiology the branch of psychology that is concerned with the physiological bases of psychological processes...

 and biological psychology/cognitive neuroscience
Cognitive neuroscience
Cognitive neuroscience is an academic field concerned with the scientific study of biological substrates underlying cognition, with a specific focus on the neural substrates of mental processes. It addresses the questions of how psychological/cognitive functions are produced by the brain...

.

Experiments on humans have been put under some controls, namely informed and voluntary consent. After World War II, the Nuremberg Code
Nuremberg Code
The Nuremberg Code is a set of research ethics principles for human experimentation set as a result of the Subsequent Nuremberg Trials at the end of the Second World War.- Background :...

 was established, because of Nazi abuses of experimental subjects. Later, most countries (and scientific journals) adopted the Declaration of Helsinki
Declaration of Helsinki
The Declaration of Helsinki, was developed by the World Medical Association , as a set of ethical principles for the medical community regarding human experimentation, and is widely regarded as the cornerstone document of human research ethics...

. In the US, the National Institutes of Health
National Institutes of Health
The National Institutes of Health is an agency of the United States Department of Health and Human Services and is the primary agency of the United States government responsible for biomedical and health-related research. It consists of 27 separate institutes and centers which includes the Office...

 established the Institutional Review Board
Institutional review board
An institutional review board , also known as an independent ethics committee or ethical review board is a committee that has been formally designated to approve, monitor, and review biomedical and behavioral research involving humans with the aim to protect the rights and welfare of the research...

 in 1966, and in 1974 adopted the National Research Act
National Research Act
The National Research Act was enacted by the 93rd United States Congress. It created the National Commission for the Protection of Human Subjects of Biomedical and Behavioral Research to oversee and regulate the use of human experimentation in medicine. It was partly a response to the infamous...

 (HR 7724). All of these measures encouraged researchers to obtain informed consent from human participants in experimental studies. A number of influential studies led to the establishment of this rule; such studies included the MIT and Fernald School radioisotope studies, the Thalidomide tragedy, the Willowbrook hepatitis
Hepatitis
Hepatitis implies injury to the liver characterized by the presence of inflammatory cells in the tissue of the organ. The name is from ancient Greek hepar , the root being hepat- , meaning liver, and suffix -itis, meaning "inflammation"...

 study, and Stanley Milgram
Stanley Milgram
Stanley Milgram was an American social psychologist most notable for his controversial study known as the Milgram Experiment. The study was conducted in the 1960s during Milgram's professorship at Yale...

's studies of obedience to authority.

Survey questionnaires


Statistical surveys are used in psychology for measuring attitudes and traits, monitoring changes in mood, checking the validity of experimental manipulations, and for a wide variety of other psychological topics. Most commonly, psychologists use paper-and-pencil surveys. However, surveys are also conducted over the phone or through e-mail. Increasingly, web-based surveys are being used in research. Similar methodology is also used in applied setting, such as clinical assessment and personnel assessment.

Longitudinal studies


A longitudinal study
Longitudinal study
A longitudinal study is a correlational research study that involves repeated observations of the same items over long periods of time — often many decades. It is a type of observational study. Longitudinal studies are often used in psychology to study developmental trends across the life...

 is a research method which observes a particular population over time. For example, one might wish to study specific language impairment
Specific language impairment
Specific language impairment is a developmental language disorder that can affect both expressive and receptive language. SLI is defined as a "pure" language impairment, meaning that is not related to or caused by other developmental disorders, hearing loss or acquired brain injury.However, the...

 (SLI) by observing a group of individuals with the condition over a period of time. This method has the advantage of seeing how a condition can affect individuals over long time scales. However, such studies can suffer from attrition due to drop-out or death of subjects. In addition, since individual differences between members of the group are not controlled, it may be difficult to draw conclusions about the populations.
Longitudinal study is a developmental research strategy that involves testing an age group repeatedly over many years. Longitudinal studies answer vital questions about how people develop. This developmental research follows people over years and the outcome has been an incredible array of findings, especially relating to psychological problems.

Some longitudinal studies are experiments, called repeated-measures experiments
Repeated measures design
A repeated measures design is a longitudinal study, usually a controlled experiment but sometimes an observational study .-Crossover studies, an example of a repeated measures design:...

. Psychologists often use the crossover design
Crossover study
A crossover study is a longitudinal study in which subjects receive a sequence of different treatments . While crossover studies can be observational studies, many important crossover studies are controlled experiments, which are discussed in this article...

 to reduce the influence of confounding covariate
Covariate
In statistics, a covariate is a variable that is possibly predictive of the outcome under study. A covariate may be of direct interest or it may be a confounding or interacting variable....

s and to reduce the number of subjects
Efficiency (statistics)
In statistics, efficiency is a term used in the comparison of various statistical procedures and, in particular, it refers to a measure of the desirability of an estimator or of an experimental design...

.

Observation in natural settings


In the same way Jane Goodall
Jane Goodall
Dame Jane Goodall, DBE is an English UN Messenger of Peace, primatologist, ethologist, and anthropologist...

 studied the role of chimpanzee
Chimpanzee
Chimpanzee, sometimes colloquially chimp, is the common name for the two extant species of ape in the genus Pan. The Congo River forms the boundary between the native habitat of the two species:...

 social and family life, psychologists conduct similar observational studies in human social, professional and family lives. Sometimes the participants are aware they are being observed and other times it is covert: the participants do not know they are being observed. Ethical guidelines need to be taken into consideration when covert observation is being carried out.

Qualitative and descriptive research


Research designed to answer questions about the current state of affairs such as the thoughts, feelings and behaviors of individuals is known as descriptive research. Descriptive research can be qualitative or quantitative in orientation. Qualitative research is descriptive research that is focused on observing and describing events as they occur, with the goal of capturing all of the richness of everyday behavior and with the hope of discovering and understanding phenomena that might have been missed if only more cursory examinations have been made.

Neuropsychological methods


Neuropsychology
Neuropsychology
Neuropsychology is the basic scientific discipline that studies the structure and function of the brain related to specific psychological processes and overt behaviors. The term neuropsychology has been applied to lesion studies in humans and animals...

 involves the study of both healthy individuals and patients, typically who have suffered either brain injury
Brain damage
Brain damage, or acquired brain injury, is the destruction or degeneration of brain cells.-Causes:Brain damage may occur due to a wide range of conditions, illnesses, injuries, and as a result of iatrogenesis...

 or mental illness
Mental illness
A mental disorder or mental illness is a psychological or behavioral pattern that occurs in an individual and is thought to cause distress or disability that is not expected as part of normal development or culture. The recognition and understanding of mental disorders has changed over time and...

.

Cognitive neuropsychology
Cognitive neuropsychology
Cognitive neuropsychology is a branch of cognitive psychology that aims to understand how the structure and function of the brain relates to specific psychological processes. It places a particular emphasis on studying the cognitive effects of brain injury or neurological illness with a view to...

 and cognitive neuropsychiatry
Cognitive neuropsychiatry
Cognitive neuropsychiatry is a sub-discipline of psychology and psychiatry that aims to understand mental illness and psychopathology in terms of models of normal psychological function. It is also a way of uncovering normal psychological processes by studying the effects of their change or...

 study neurological or mental impairment in an attempt to infer theories of normal mind and brain function. This typically involves looking for differences in patterns of remaining ability (known as 'functional disassociations') which can give clues as to whether abilities are comprised of smaller functions, or are controlled by a single cognitive mechanism.

In addition, experimental techniques are often used to study the neuropsychology of healthy individuals. These include behavioral experiments, brain-scanning or functional neuroimaging
Functional neuroimaging
Functional neuroimaging is the use of neuroimaging technology to measure an aspect of brain function, often with a view to understanding the relationship between activity in certain brain areas and specific mental functions...

, used to examine the activity of the brain during task performance, and techniques such as transcranial magnetic stimulation
Transcranial magnetic stimulation
Transcranial magnetic stimulation is a noninvasive method to excite neurons in the brain: weak electric currents are induced in the tissue by rapidly changing magnetic fields...

, which can safely alter the function of small brain areas to reveal their importance in mental operations.

Computational modeling


Computational modeling
Computer simulation
A computer simulation, a computer model, or a computational model is a computer program, or network of computers, that attempts to simulate an abstract model of a particular system...

 is a tool often used in mathematical psychology
Mathematical psychology
Mathematical psychology is an approach to psychological research that is based on mathematical modeling of perceptual, cognitive and motor processes, and on the establishment of law-like rules that relate quantifiable stimulus characteristics with quantifiable behavior...

 and cognitive psychology
Cognitive psychology
Cognitive psychology is a discipline within psychology that investigates the internal mental processes of thought such as visual processing, memory, problem solving, and language....

 to simulate a particular behavior using a computer. This method has several advantages. Since modern computers process extremely quickly, many simulations can be run in a short time, allowing for a great deal of statistical power. Modeling also allows psychologists to visualize hypotheses about the functional organization of mental events that couldn't be directly observed in a human.

Several different types of modeling are used to study behavior. Connectionism
Connectionism
Connectionism is a set of approaches in the fields of artificial intelligence, cognitive psychology, cognitive science, neuroscience and philosophy of mind, that models mental or behavioral phenomena as the emergent processes of interconnected networks of simple units...

 uses neural network
Neural network
Traditionally, the term neural network had been used to refer to a network or circuit of biological neurons. The modern usage of the term often refers to artificial neural networks, which are composed of artificial neurons or nodes...

s to simulate the brain. Another method is symbolic modeling, which represents many different mental objects using variables and rules. Other types of modeling include dynamic systems and stochastic
Stochastic process
In probability theory, a stochastic process, or sometimes random process, is the counterpart to a deterministic process...

 modeling.

Animal studies


Animal learning experiments are important in many aspects of psychology such as investigating the biological basis of learning, memory and behavior. In the 1890s, physiologist Ivan Pavlov
Ivan Pavlov
Ivan Petrovich Pavlov was a Russian, and later Soviet, physiologist, psychologist, and physician. He was awarded the Nobel Prize in Physiology or Medicine in 1904 for research pertaining to the digestive system...

 famously used dogs to demonstrate classical conditioning
Classical conditioning
Classical conditioning is a form of associative learning that was first demonstrated by Ivan Pavlov. The typical procedure for inducing classical conditioning involves presentations of a neutral stimulus along with a stimulus of some significance...

. Non-human primates
Animal testing on non-human primates
Experiments involving non-human primates include toxicity testing for medical and non-medical substances; studies of infectious disease, such as HIV and hepatitis; neurological studies; behavior and cognition; reproduction; genetics; and xenotransplantation. Around 65,000-70,000 are used every...

, cats, dogs, rats
Laboratory rat
A laboratory rat is a rat of the species Rattus norvegicus which is bred and kept for scientific research. Laboratory rats have served as an important animal model for research in psychology, medicine, and other fields.- History :...

 and other rodents
Animal testing on rodents
Rodents are commonly used in animal testing, particularly guinea pigs, hamsters, gerbils, rats, and mice.-Numbers:In the UK in 2004, 1,910,110 mice, 464,727 rats and 37,475 other rodents were used...

 are often used in psychological experiments. Controlled experiments involve introducing only one variable at a time, which is why animals used for experiments are housed in laboratory settings. In contrast, human environments and genetic backgrounds vary widely, which makes it difficult to control important variables for human subjects.

Theory


Criticisms of psychology often come from perceptions that it is a "fuzzy" science. Philosopher Thomas Kuhn's 1962 critique implied psychology overall was in a pre-paradigm state, lacking the agreement on overarching theory found in mature sciences such as chemistry
Chemistry
Chemistry is the science concerned with the composition, behavior, structure, and properties of matter, as well as the changes it undergoes during chemical reactions...

 and physics
Physics
Physics is a natural science; it is the study of matter and its motion through spacetime and all that derives from these, such as energy and force...

. Psychologists and philosophers have addressed the issue in various ways.

Because some areas of psychology rely on research methods such as surveys and questionnaire
Questionnaire
A questionnaire is a research instrument consisting of a series of questions and other prompts for the purpose of gathering information from respondents. Although they are often designed for statistical analysis of the responses, this is not always the case...

s, critics have asserted that psychology is not scientific (due to the largely correlational nature of survey research). Other phenomena that psychologists are interested in, such as personality
Personality psychology
Personality psychology is a branch of psychology that studies personality and individual differences.Its areas of focus include:* Constructing a coherent picture of a person and his or her major psychological processes...

, thinking, and emotion
Emotion
An emotion is a mental and physiological state associated with a wide variety of feelings, thoughts, and behavior. Emotions are subjective experiences, often associated with mood, temperament, personality, and disposition. The English word 'emotion' is derived from the French word émouvoir...

, cannot be directly measured and are often inferred from subjective self-reports, which may be problematic.

Misuses of hypothesis-testing
Statistical hypothesis testing
A statistical hypothesis test is a method of making statistical decisions using experimental data. In statistics, a result is called statistically significant if it is unlikely to have occurred by chance...

 occur in psychology, particularly by psychologists without doctoral training in experimental psychology and statistics. Research has documented that many psychologists confuse statistical significance
Statistical significance
In statistics, a result is called statistically significant if it is unlikely to have occurred by chance. The phrase test of significance was coined by Ronald Fisher....

 with practical importance
Effect size
In statistics, an effect size is a measure of the strength of the relationship between two variables in a statistical population, or a sample-based estimate of that quantity...

. Statistically significant but practically unimportant results are common with large samples. Some psychologists have responded with an increased use of effect size
Effect size
In statistics, an effect size is a measure of the strength of the relationship between two variables in a statistical population, or a sample-based estimate of that quantity...

 statistics, rather than sole reliance on the Fisherian p < .05 significance
Statistical significance
In statistics, a result is called statistically significant if it is unlikely to have occurred by chance. The phrase test of significance was coined by Ronald Fisher....

 criterion (whereby an observed difference is deemed "statistically significant"
Statistical significance
In statistics, a result is called statistically significant if it is unlikely to have occurred by chance. The phrase test of significance was coined by Ronald Fisher....

 if an effect of that size or larger would occur with 5% (or less) probability
Frequency probability
Frequency probability is the interpretation of probability that defines an event's probability as the limit of its relative frequency in a large number of trials. The development of the frequentist account was motivated by the problems and paradoxes of the previously dominant viewpoint, the...

 in independent replications
Replication (statistics)
In engineering, science, and statistics, replication is the repetition of an experimental condition so that the variability associated with the phenomenon can be estimated. ASTM, in standard E1847, defines replication as "the repetition of the set of all the treatment combinations to be compared in...

, assuming the truth of the null-hypothesis
Null hypothesis
In statistical hypothesis testing, the null hypothesis formally describes some aspect of the statistical "behaviour" of a set of data. This description is assumed to be valid unless the actual behaviour of the data contradicts this assumption. Thus, the null hypothesis is contrasted against...

 of no difference between the treatments).

Sometimes the debate comes from within psychology, for example between laboratory-oriented researchers and practitioners such as clinicians. In recent years, and particularly in the U.S., there has been increasing debate about the nature of therapeutic effectiveness and about the relevance of empirically examining psychotherapeutic strategies. One argument states that some therapies are based on discredited theories and are unsupported by empirical evidence. The other side points to recent research suggesting that all mainstream therapies are of about equal effectiveness, while also arguing that controlled studies often do not take into consideration real-world conditions.

Practice


Some observers perceive a gap between scientific theory and its application—in particular, the application of unsupported or unsound clinical practices. Critics say there has been an increase in the number of mental health training programs that do not instill scientific competence. One skeptic asserts that practices, such as "facilitated communication
Facilitated communication
Facilitated communication is a process by which a facilitator supports the hand or arm of a communicatively impaired individual while using a keyboard or other devices with the aim of helping the individual to develop pointing skills and to communicate...

 for infantile autism"; memory-recovery techniques including body work; and other therapies, such as rebirthing
Rebirthing
Rebirthing may refer to:*Rebirthing-Breathwork, a form of alternative medicine mainly consisting of a breathing technique* Rebirthing , where a child is laid upon to produce a cathartic response...

 and reparenting
Reparenting
Reparenting is a therapy concerned with "healing the inner child". It involves treating problems caused by neglect, criticism, or sexual abuse from parents, and uses a range of methods involving self affirmations, anger workouts, self forgiveness, and letting go of shame and guilt....

, may be dubious or even dangerous, despite their popularity. In 1984, Allen Neuringer had made a similar point regarding the experimental analysis of behavior.

See also



External links