A psychological adaptation
, also called an Evolved psychological mechanism or EPM
, is an aspect of a human or other animal's psychology that is the result of evolution
Evolution is any change across successive generations in the heritable characteristics of biological populations. Evolutionary processes give rise to diversity at every level of biological organisation, including species, individual organisms and molecules such as DNA and proteins.Life on Earth...
ary pressures. It could serve a specific purpose, have served a purpose in the past (see vestigiality), or be a side-effect of another EPM (see spandrel (biology)
In evolutionary biology, a Spandrel is a phenotypic characteristic that is a byproduct of the evolution of some other characteristic, rather than a direct product of adaptive selection.-Origin of Term:...
). Evolutionary psychology
Evolutionary psychology is an approach in the social and natural sciences that examines psychological traits such as memory, perception, and language from a modern evolutionary perspective. It seeks to identify which human psychological traits are evolved adaptations, that is, the functional...
proposes that the human psychology mostly comprises psychological adaptations, in opposition to blank slate
Tabula rasa is the epistemological theory that individuals are born without built-in mental content and that their knowledge comes from experience and perception. Generally proponents of the tabula rasa thesis favour the "nurture" side of the nature versus nurture debate, when it comes to aspects...
models of human psychology such as the standard social science model
The term the Standard Social Science Model was first introduced to a wide audience by John Tooby and Leda Cosmides in the 1992 edited volume The Adapted Mind, to describe the "blank slate," social constructionist,or "cultural determinist" perspective that they claim is the dominant theoretical...
popular throughout most of the twentieth century.
Evolutionary psychologist, David Buss
David M. Buss is a professor of psychology at The University of Texas at Austin, known for his evolutionary psychology research on human sex differences in mate selection.-Biography:...
, lays out six properties of evolved psychological mechanisms (EPM's):
- An EPM exists in the form that it does because it solved a specific problem of survival or reproduction recurrently over evolutionary history.
- An EPM is designed to take in only a narrow slice of information
- The input of an EPM tells an organism the particular adaptive
An adaptation in biology is a trait with a current functional role in the life history of an organism that is maintained and evolved by means of natural selection. An adaptation refers to both the current state of being adapted and to the dynamic evolutionary process that leads to the adaptation....
problem it is facing
- The input of an EPM is transformed through decision rules
Decision theory in economics, psychology, philosophy, mathematics, and statistics is concerned with identifying the values, uncertainties and other issues relevant in a given decision, its rationality, and the resulting optimal decision...
- The output of an EPM can be physiological activity, information to other psychological mechanisms, or manifest behaviors
- The output of an EPM is directed toward the solution to a specific adaptive problem
Further important properties include the following:
- EPM's provide nonarbitrary criteria, (i.e. adaptive function) for "carving the mind at its joints," (i.e. evolved structure).
- EPM's tend to aid in solving specific adaptive problems, (e.g. food selection, mate selection, intrasexual competition, etc.)
- EPM's are believed to be numerous, which contributes to human behavioral flexibility. An analogy would be like a carpenter who, instead of having one tool that does everything, has many tools, each with a specific function for a specific task, (e.g. a hammer for pounding nails, a saw for cutting wood, etc.)
- Some EPM's are domain-specific, (i.e. evolved to solve specific, recurrent adaptive problems), while others are domain-general, (i.e. evolved to aid the individual in dealing with novelty in the environment).
The least controversial EPMs are those commonly known as instinct
Instinct or innate behavior is the inherent inclination of a living organism toward a particular behavior.The simplest example of an instinctive behavior is a fixed action pattern, in which a very short to medium length sequence of actions, without variation, are carried out in response to a...
s, including interpreting stereoscopic
Stereoscopy refers to a technique for creating or enhancing the illusion of depth in an image by presenting two offset images separately to the left and right eye of the viewer. Both of these 2-D offset images are then combined in the brain to give the perception of 3-D depth...
vision and suckling
Breastfeeding is the feeding of an infant or young child with breast milk directly from female human breasts rather than from a baby bottle or other container. Babies have a sucking reflex that enables them to suck and swallow milk. It is recommended that mothers breastfeed for six months or...
a mother's breast.