Memory errors
Encyclopedia
Memory gaps and errors refer to the incorrect recall
, or complete loss, of information in the memory
system for a specific detail and/or event. Memory errors may include remembering events that never occurred, or remembering them differently from the way they actually happened. These errors or gaps can occur due to a number of different reasons, including the emotional involvement in the situation, expectations and environmental changes. As the retention interval between encoding
and retrieval of the memory lengthens, there is an increase in both the amount that is forgetten, and the likelihood of a memory error occurring.
, or to physiological factors, including brain damage
, age or emotional factors. Furthermore, memory errors have been reported in individuals with schizophrenia
and depression
. The consequences of memory errors can have significant implications. Two main areas of concern regarding memory errors are in eyewitness testimony
and cases of child abuse
.
, sometimes referred to as confabulation
, refer to the recollection of inaccurate details of an event, or recollection of a whole event that never occurred. Studies investigating this memory error have been able to successfully implant memories among participants that never existed, such as being lost in a mall as a child (termed the lost in the mall technique
) or spilling a bowl of punch at a wedding reception. In this case, false memories were implanted among participants by their family members who claimed that the event had happened. This evidence demonstrates the possibility of implanting false memories on individuals by leading them to remember such events that never occurred. This memory error can be particularly worrisome in judicial settings, in which witnesses may have false recollections of a crime after it has happened, especially when told by others that particular things may have happened which did not. Another area of concern regarding false memories is in cases of child abuse. Some people believe therapists plant false memories into patients, leading them to believe that they have experienced abuse in their childhood even though they did not.
refers to the change in memory due to the presentation of information that is relevant to the target memory, such as leading questions or suggestions. Memories are likely to be altered when questions are worded differently or when inaccurate information is presented. For example, in one experiment participants watched a video of an automobile accident and were then asked questions regarding the accident. When asked how fast the automobiles were driving when they smashed into each other, the speed estimate was higher than when asked how fast the automobiles were driving when they hit, bumped or collided into each other. Similarly, participants were more likely to report there being shattered glass present when the word smashed was used instead of other verbs. Evidently, memory recollection can be altered with misleading information after the event.
. That is, when one imagines an event occurring, their confidence that this event actually did occur increases. One reason for this may be due to the act of imagination increasing the familiarity of the event. When the event seems more familiar, it may become more likely for people to report it actually occurring. For instance, in an experiment participants were asked to imagine playing inside and then running outside toward a window, falling and breaking it, while other participants did not imagine anything. Participants who had imagined this scenario reported an increased level of confidence that the event had actually happened in comparison to those who did not imagine the event. This error can be caused simply by imagining an event.
refers to the incorrect recall of features of an event that were not actually present, due to the features being related to a common theme. This paradigm has been demonstrated with the use of word lists and subsequent recognition tests. For example, experiments have shown that if a research participant is presented with the words: bed rest awake tired dream wake snooze snore nap yawn drowsy, there is a high likelihood that the participant will falsely recall that the word sleep was in the list of words. These results show a significant illusion in memory, in which people remember items that were never presented simply due to their relation with other items in a common theme.
to help reconstruct parts of an experience that cannot be remembered. This may include parts of the schema that did not actually take place, or aspects of a schema that are stereotypical of an event. Schemas can be described as mental guidelines (scripts) for events that are encountered in daily life. For example, when going to the gas station, there is a general pattern of how things will occur (i.e. turn car off, get out of car, open gas tank, punch the gas button, put nozzle into the tank, fill up the tank, put the nozzle back, close the tank, pay, turn car on, leave). Schemas make the world more predictable, allowing expectations to be formed of how things will enfold and to take note of things that happen out of context. However, schemas also allow for memory errors, in that if certain aspects of a scene or event are missing from memory, people may incorrectly remember having actually seen or experienced them due to the fact they are usually a regular aspect of the schema. For example, an individual may not remember paying the waiter, but may believe they have done so, as this is a regular step in the script of going to a restaurant. Similarly, a person may recall seeing a fridge in a picture of a kitchen, even if one was not actually depicted due to existing schemas which suggest that kitchens almost always contain a fridge.
, in which the memory information from one time impairs the recall of information from a different time. (see interference below). A second theory is that intrusion errors may be responsible, in that memories revolving around a similar time period thus share a common theme, and memories of various points of time within that larger time period become mixed with each other and intrude on each others’ recall. Last, the recall of memories often have holes due to forgotten details. Thus, individuals may be using a script (see schema errors) to help fill in these holes with general knowledge of what they know happened around this time. Since scripts are a time-based knowledge structure, which puts details of a memory in sequence to make it easier to understand, time-slice errors can occur if a detail is mistakenly placed in the wrong sequence.
. The first factor is time. As time passes, memories fade. Therefore, source confusion may result due to time delay. The second factor is the imagination inflation effect. As the amount of imagination increases, so does one’s familiarity for the contents of the imagination. Thus, source confusion may also occur due to the individual confusing the source of the memory for being true, when in fact it was imaginary. Lastly, social pressure to recall the memory may affect the individual’s belief in the false memory. For example, with increase in pressure, the individual may lower their criteria for validating a memory, and come to accept a false memory
for being true. Personal life effects can be extremely crucial to recognize in cases of recovered memories
, especially those of abuse, in which the individual may have been led to believe they had been abused as a child by a therapist during psychological therapy, when in fact they had not been. Personal life effects can also be important in witness testimonies, in which suggestions from authorities may incorrectly implant memories regarding witnesses a particular detail about a crime (see the Childhood Abuse and Eye Witness Testimony sections below).
One theory on how memory works is through a concept called spreading activation. Spreading activation
refers to the firing of connected nodes in associated memory links. The theory states that memory is organized in a theoretical web of associated ideas and related features. Each feature, or node, is connected to related features or ideas, which in turn are themselves connected to other related nodes. The theory of spreading activation states that, when you think about a specific idea/object, that node becomes activated and fires, causing the connections of related features to also become activated, to a lesser degree. This theory explains the theory of retrieval cues, in which a cue that is related to a target memory is used to help remember a certain memory.
Spreading activation can also demonstrate how memory errors may occur. As the network of memory associations increases in the number of connections–the connection density–the likelihood of memory gaps and errors occurring also increases. Put simply, the amount of activation a secondary connection receives depends on how many connections the initial node has associated with it. This is because the initial node must divide the amount of activation it spreads to related nodes by the number of connecting nodes it is associated with. If node 1 has three connecting nodes, and node 2 has 15 connecting nodes, the three connecting nodes from node 1 will receive greater activation levels (the activation level is divided less) than for the 15 connecting nodes from node 2, and the components of these nodes will be more easily brought to mind. What this means is that, with more connections a node has, the more difficulty there is bringing to mind one of its connecting features. This can lead to memory errors, in that if the connection density is so great that there is not enough activation reaching the secondary nodes, then the person may not recall a target memory that is actually present, and a memory error occurs.
Activation levels to secondary nodes is also determined by the strength of the association to the primary node. Some connections have greater association with the primary node (e.g. fire truck and fire or red, versus fire truck and hose or Dalmatian), and thus will receive a greater portion of the divided activation than less associated connections. Thus, associations that receive less activation will be out-competed by associations with stronger connections, and may fail to be brought into awareness, again causing a memory error.
Connection density
The connection densities, or neighbourhood densities of memory arrangements help distinguish which elements are a part of, or related to, the target memory. As the density of neural networks increases, the number of retrieval cues (associated nodes) also increases, which may allow for enhanced memory of the event. However, too many connections can inhibit memory in two ways. First, as described under the sub-section Spreading Activation, the total activation being spread from node 1 to connecting nodes is divided by the number of connections. With a greater number of connections, each connecting node receives less activation, which may result in too little activation for the memory cue to be brought to awareness. Connection strength, in which more strongly connected associations receive more activation than less-related associations, may also prevent specific connections from being brought to awareness due to being out-competed by the stronger associations. Second, with more connections branching from various other nodes, there is a greater probability of linking associated connections of different memories together (transplant errors) so that memory errors occur and incorrect features are recalled.
Retrieval cues
A retrieval cue is a type of hint that can be used to evoke a memory that has been stored but cannot be recalled. Retrieval cues work by selecting traces or associations in memory that contain specific content. With regards to the theory of spreading activation, retrieval cues use associated nodes to help activate a specific or target node. When no cues are available, recall is greatly reduced, leading to forgetting and possible memory errors. This is called retrieval failure, or cue-dependent forgetting
.
Retrieval cues can be divided into two subsets, although they are by no means used independent of each other. The first are called feature cues, in which information of the content of the original memory, or related content, is used to aid recall. The second category is context cues, in which information based on the specific context (environment) in which the memory or learning occurred is used to aid recall.
Although retrieval cues are usually helpful in helping to remember something, they can produce memory errors in three ways. First, incorrect cues can be used, leading to recall of an incorrect memory. Second, although the correct retrieval cues may be used, they may still produce an incorrect memory. This is likely to occur with high connection densities, in which the incorrect (but associated) node was activated and thus recalled, instead of the target memory. Third, the retrieval cue chosen may be correct and associated with the target memory, but it may not have a strong connection to the target memory, and thus may not produce enough activation to produce the target memory.
Encoding specificity
Encoding specificity
is when retrieval is successful to the extent that the retrieval cues used to help recall, match the cues the individual used during learning or encoding. Memory errors due to encoding specificity means that the memory is likely not forgotten, however, the specific cues used during encoding the primary event are now unavailable to help remember the event. The cues used during encoding are dependent on the environment of the individual at the time the memory occurred. In context-dependent memory, recall is based on the difference between the encoding and recall environments. Recall for items learned in a particular context is better when recall occurs in the same place as when the initial memory occurred. This is why it is sometimes useful to “return to the scene of the crime” to help witnesses remember details of a crime, or for explaining why going to a specific location such as a residence or community setting, may lead to becoming flooded with memories of things that happened in that context. Recall can also depend on state-dependency, or the conditions of one's internal environment, at both the time of the event and of recall. For example, if intoxicated at the time the memory actually occurred, recall for details of the event is greater when recalling while intoxicated. Associated with state-dependency, recall can also depend on mood-dependency, in which recall is greater when the mood for when the memory occurred matches the mood during recall. These specific dependencies are based on the fact that the cues used during the initial event can be specific to the context or state one was in. In other words, various features of the environment (both internal and external) can be used to help encode the memory, and thus become retrieval cues. However, if the context or state changes at the time of recall, these cues may no longer be available, and thus recall is hindered.
Transfer-appropriate processing
Memory errors can also depend on the method of encoding used when initially experiencing or learning information, known as transfer-appropriate processing
. Encoding processes can occur at three levels: visual form (the letters that make up a word), phonology (the sound of a word), and semantics (the meaning of the word or sentence). With relation to memory errors, the level of processing at the time of encoding and at the time of recall should be the same. Although semantic processing generally produces greater recall that shallower levels of processing, a study by Morris et al. demonstrated that what might be the key factor to greater recall is transfer-appropriate processing–when the level of processing at the original memory/learning time matches the level of processing used to help recall. In other words, if learning occurred by rhyming the target words to other words, then recall is best if testing is also at the phonological level of processing, such as a rhyming recognition test. Thus, memory errors can occur when the levels of processing between encoding and recall do not match.
Interference
Interference
occurs when specific information inhibits learning and /or recall for a specific memory. There are two forms of interference. First, proactive interference has to do with difficulty in learning new material based on the inability to override information from older memories. In such cases, retrieval cues continue to be associated and aimed at recalling previously learned information, affecting the recall of new material. Retroactive interference is the opposite of proactive interference, in which there is difficulty in the recall of previously learned information based on the interference of newly acquired information. In this case, retrieval cues are associated with the new information and not the older memory. thus affecting recall of older material. Interference of either form can produce memory errors, in which there is interference with the recall of material. In other words, previously used retrieval cues are no longer associated with prior memories, and thus memory confusion or even an inability to recall the memory can occur.
Neuroimaging
studies have provided evidence for links between brain damage and memory errors. Brain areas implicated include the frontal lobe
and medial-temporal
regions of the brain. Such damage may result in significant confabulation
s and source confusion.
The prefrontal cortex
is in charge of making heuristic
judgments and systematic judgments, which involve analyzing the qualities of memories and the retrieval and evaluation of supporting or disconfirming information. Thus, if the frontal region is damaged, these abilities will be impaired and memories may not be retrieved or evaluated correctly. For example, one patient who suffered frontal lobe damage after an automobile accident reported memories of the support his family provided for him after the accident, which in reality, was false.
The temporal
region of the brain contains the hippocampus
, which plays a significant role in memory
. Thus, damage in this region may impair the function of this brain structure and result in memory problems.
Age
Studies have shown that the likelihood of memory errors occurring increases as age increases. Possible reasons for this are increased source confusion
for the event and findings that older persons have decreased levels of processing when first presented with new information. Source confusion refers to the inability to distinguish how one came upon different information. Older individuals can become confused with where they learnt information (e.g. TV, radio, newspaper, word of mouth, etc.), who presented them with the information (e.g. which of two experimenters presented them with facts and which presented them with irrelevant information), and whether the information came from an imagined source, and is thus not factual, or a real world source. This in itself is a form of memory error but can also create larger memory errors. When an older individual is confused whether the information is factual or was imagined they can begin to accept imagined memories as real and thus begin to rely on new false information. Levels of processing refers to the manner in which someone encodes information into their memory and how deeply it is encoded. There are three different levels of processing ranging from shallow to deep, deep being stored in long-term memory for a longer period and thus better remembered. The three levels are; visual form, being the shallowest form, phonology
, being a medium level of processing, and semantics
(meaning), which is the deepest form of processing. The visual form of processing relies on the ability to see information and break it down into its components (e.g. see the word "dog", composed D, O, and G). Phonology relies on creating links to information through sound such as cues and tricks for memory (e.g. Dog rhymes with Fog). Finally, semantics refer to the creation of meaning behind information such as adding detail to allow the information to create links throughout our memory with other memories and thus be held in long-term memory for a longer period (e.g. A dog is a four-legged pet that often chases cats and chews on bones). Older individuals often begin to lose the quick ability to add meaning to new information, which leads to shallower processing and easier forgetting of the information gained. Both of these possible factors can decrease the validity of the memory due to retrieval for details of the event being more difficult to perform. This leads to details of memories being confused with others or lost completely, which lead to many errors in recall of a memory.
Emotion
The emotional impact of an event can have a direct impact on how the memory is first encoded, how it is later recalled, and what details of the event are accurately recalled. Highly emotional events tend to be recalled easily due to their emotional impact, as well as their distinctiveness relative to other memories (highly emotional events do not occur on a regular basis, and thus are easily separated from other events that are more commonly met). Emotional events may affect memory not only because of their distinctiveness, but also because of their arousal on the individual. Studies have found that prime or central features of such highly emotional events tend to be accurately recalled, whereas subtle details of the events are not remembered, or are remembered with vague consistency. Memory errors related to highly emotional events are influenced in ways such as:
• Whether the event was positive or negative in nature - The nature of the event can affect memory, negative events tend to be remembered with greater accuracy than positive events.
• Implicit theories of consistency and change - This term was coined by Ross (1989), and is used to describe the phenomena of memory change based on the belief of how the person felt at the time of the event compared to their current feelings about it. In other words, the memory of one's emotion towards an event can change depending on their current emotional state toward the same event. If a person believes their feelings at both times continue to be the same, then the current emotion to "remember" how they felt about the event at a previous time is used. If feelings are believed to have changed, then recall of the emotional involvement in the past event is adjusted to the current feelings.
• Intrusion errors - This term refers to the inclusion of details that may have been commonly experienced in the event, but not by the individual. For example, in the September 11 terrorist attacks, many people may state that they remember hearing about the attacks on the television news, as this was a common way of finding out this information, whereas they may have actually heard about it from a neighbour or on the radio.
• Mood-congruency - Items/events are better recalled when the mood of the individual at the time of the event and the time of recall are the same. Thus, if the mood at the time of recall does not match the mood experienced at the time the event occurred, there is an increased chance that complete recall will be affected/interrupted.
is the branch of psychology that studies unusual patterns of behavior, emotion and thought, which may or may not be understood as a mental disorder. Memory errors can commonly be found in types of abnormal psychology such as Alzheimer's Disease
, depression
and schizophrenia
.
priming
tasks. Patients also demonstrate errors known as misattribution errors, otherwise known as source confusion. However, studies show that these misattribution errors are dependent on whether the task is a familiarity or recollection tas. Although patients tend to exhibit a higher level of false recognitions than control groups. researchers have shown that they may exhibit less false-recognition early in the test due to familiarity being slower to develop. However, the observation of increasing instances of misattribution errors can be seen once familiarity does occur. This may be related to the retrieval cue speculation, in that familiar memories often contain cues we know, and thus may be the reason why familiarity can contribute to memory errors. Lastly, many studies have shown that Alzheimer’s patients commonly suffer from intrusion errors. Relative to the findings that retrieval cues may actually hurt recall performance, one study by Kramer et al. showed that intrusions are most commonly associated with cue-recall tasks. This study suggests that cues may lead to intrusions because patients may have a difficult time distinguishing between cues and distractions, which may help explain why cues increase memory errors in patients with Alzheimer’s. Since verbal intrusions are a common aspect of Alzheimer’s. some researchers believe that this characteristic may be helpful in the diagnosis of the disease.
, which is the perspective use of negative schemas and self-concepts to relate to the external world. Due to this negative triad, depressive patients have a tendency to have a much greater focus on, and recall for, negative details and events over positive ones. This may lead to memory errors related to the positive details of memories, impairing the accuracy or even complete recall of such memories. Depressed patients also experience deficits in psychomotor speed and in free recall of material both immediate and delayed. This suggests that material has been encoded but that patients are particularly impaired with regard to search and retrieval processes. Diverse aspects of memory such as short-term memory
, long-term memory, semantic memory
and implicit memory
, have been studied and linked to depression. Short-term memory, a temporary store for newly acquired information, seems to show no major impairments in the case of depressive patients who do seem to complain about poor concentration, which by itself can cause simple memory errors. Long-term memory, large capacity able to retain information over long periods of time, does however show impairment in the case of depressed individuals. They tend to have difficulties in recall and recognition for both verbal and visuo-spatial material with intervals of a few minutes or even hours creating complex memory errors in relation to speech and surrounding details. Individuals suffering with depression also showed a specific deficit in retrieving information meaningfully organized in their semantic memory, conceptual knowledge about the real world. Therefore, depressive patients can show memory errors for the most meaningful events in their lives, unable to recall these specific moments vividly like someone not suffering from depression might. In the case of implicit memory, when previous information influences ongoing responses, there has been little to no proof of a deficit in relations to depressed individuals.
, which involve an excess of normal bodily functions (e.g. delusions), versus negative schizophrenic symptoms
, which involve a decrease in normal bodily functions (e.g. refusal to speak). Possible reasons for this are reduced function in the central executive of the working memory, as well as defects in self-reflectivity, organization and reasoning. Self-reflectivity is the ability to recognize and reason about one’s own thought process, recognize that one has thoughts, and that those thoughts are one’s own and differentiate between cognitive operations. Self-reflectivity has been shown to be one of the biggest deficits faced by schizophrenics and data suggests that verbal memory intrusions are linked to deficits in the ability to identify, organize, and reason about one's own thoughts in patients with schizophrenia.
Imagination inflation effects were also common memory errors in patients with schizophrenia. This effect refers to events that individuals have imagined so vividly in their minds that this adds belief to the fact that the event truly occurred, although it did not. Possible reasons for this are increased source confusion and/or decreased source recollection of an event, which shows poor use of source-monitoring processes
. Source-monitoring processes allow one to distinguish between a memory that we may believe has happened because it seems familiar and one that has truly occurred. In the case of schizophrenics, whose abilities to reason through their thoughts is impaired, something that they have imagined and thus, seems familiar can easily be mistaken for an actual event, especially in the case of quick heuristic processes
and snap judgments. Continuously imagining an action or event makes this action more and more familiar thus making it harder for a patient with schizophrenia to distinguish its source, questioning whether it is familiar because they have imagined it or if it is familiar because it happened. This leads to many memory errors for these individuals who are led to believe by their imagination of the event that it is real, has occurred and thus is stored in their memory for that reason.
, memory errors can lead to the creation of false traumatic childhood memories, which can lead to false accusations and loss of trust.
Such features include:
• Leading questions – refers to how wording of questions can influence how an event is remembered. This can result from a misinformation effect
or an imagination inflation effect. The misinformation effect occurs when information is presented after the events in question have occurred which leads to memory errors in later retrieval. Studies have suggested that witnesses may misattribute accuracy to misleading information because the sources of misleading information and witnessed information become confused. Misleading information can be acquired through reading of the newspaper, watching the news, being interviewed or when sitting in the courthouse during the trial. When witnesses are asked to recall specific details of an event they can begin to doubt their memory, which can cause memory errors. Misinformation can manifest itself as a memory leading the individual to believe it as true and witnesses may also begin to doubt their own memories of the event deciding instead that they must be wrong. Memory errors also occur through the imagination inflation effect. As stated earlier, the imagination inflation effect takes place when an individual imagines an event to the point where it is believed as a memory of an actual event. During trial, witnesses hear many different possible occurrences of events and are led to imagine these situations. Through imagining and rehearsal of the occurrences, witnesses may begin to see vividness and validity in the stories simply from rehearsal, not factual memories. This can create problems for witnesses when trying to distinguish between imagined events and the actual occurrence of the events. Small but largely significant details become easily mixed and these occurrences of memory errors can make or break a trial.
• Weapons Focus Effect
–refers to the fact that witnesses are highly likely to pay close attention to the weapon being used during an event, which creates a reduction in the ability to remember other details regarding the crime. This can in turn create memory errors leaving the witness less able to remember details such as what the assailant was wearing or what distinctive features could be found on their body or face. One explanation for why witnesses tend to gravitate toward the weapon being used is said to be that the arousal of the witness is increased. When arousal becomes increased the number of perceptional cues being utilized by the brain decreases. This allows the individual to focus on the weapon cue and ignore other cues such as distinct scars or a bright red shirt. The weapons focus effect can also refer to how the report of the use of weapons in the case can influence the memory of the event, leading to a false memory of having heard a weapon being fired even if the witness did not. For example, if a newspaper reports that the victim was beaten with a hammer, upon reading this, the witness will begin to believe that a hammer was in fact used, even if they at no point saw a hammer. This can cause many memory errors and conflict of stories for witnesses. As a society we believe that newspapers or televised news reports have fact behind them. If they report the hammer being used, a witness might begin to second-guess their memory wondering if they missed the hammer or failed to remember that detail. Also, their story may become mixed with the media's representation of the story and the knife that they did see will be forgotten and instead be replaced with the hammer that was reported.
• Familiarity Effect
–refers to the tendency of individuals to develop a preference for things simply because they are familiar. This can leave an individual to identify familiar people as guilty, even if they are not. When we are continuously exposed to the same object or person we begin to develop a positive attraction towards said object or person. Simply their familiarity creates a positive sense when re-exposed to the individual or object. In reality one can know very little about a person but by seeing them over and over again can gain unconscious positive recall for their face. This can create memory errors when individuals are asked to identify a criminal and someone familiar to them is placed in the line up. When a familiar face is in among the individuals that the witness is being asked to study, the witness will find himself or herself gravitating towards the familiar face whether or not this is who they witnessed committing the crime. This leaves them more likely to ignore the cues that are leading them towards other individuals and concentrate on the familiar face, resulting in a false accusation. The sense of familiarity can play a large role in the identification of criminals but when the familiarity of a criminal is mixed in with the familiarity of other individuals, choosing the right person can become quite difficult.
later in life, some mental health professionals believe in the Freudian theory of repressed memories as a defense mechanism for the anxiety that recall of the abuse would cause. Freud said that repression operates unconsciously in individuals who are not able to recall a threatening situation or may even forget that the abusive individual was ever part of their lives. Therefore, mental health professionals will sometimes seek to uncover possible instances of childhood abuse in patients, which may lead to suggestibility
and cause a false memory
of childhood abuse to arise, in an attempt to seek a cause to a mental illness No matter the confidence in the memory, this does not necessarily equate to the memory being true. This is an example of the misinformation effect
and false memory effect. The fact that memories are not retrieved as whole entities but rather are reconstructed from information remaining in memory and other related knowledge make them easily susceptible to memory errors. This explains why working with mental health professionals and leading questions
can sometimes manifest false memories by creating knowledge of possible events and asking individuals to focus on if these events actually took place Individuals begin to overthink these situations visualizing them in their mind and overanalyzing them. This in turn leads to the belief of situations and vivid memories. Patients are left with memories they believe are real and new events from their childhood which can lead to stress and trauma in their adult life and loss of relationships with those who are believed to be the abuser.
Recall (memory)
Recall in memory refers to the retrieval of events or information from the past. Along with encoding and storage, it is one of the three core processes of memory. There are three main types of recall: free recall, cued recall and serial recall...
, or complete loss, of information in the memory
Memory
In psychology, memory is an organism's ability to store, retain, and recall information and experiences. Traditional studies of memory began in the fields of philosophy, including techniques of artificially enhancing memory....
system for a specific detail and/or event. Memory errors may include remembering events that never occurred, or remembering them differently from the way they actually happened. These errors or gaps can occur due to a number of different reasons, including the emotional involvement in the situation, expectations and environmental changes. As the retention interval between encoding
Encoding (Memory)
Memory has the ability to encode, store and recall information. Memories give an organism the capability to learn and adapt from previous experiences as well as build relationships. Encoding allows the perceived item of use or interest to be converted into a construct that can be stored within the...
and retrieval of the memory lengthens, there is an increase in both the amount that is forgetten, and the likelihood of a memory error occurring.
Overview
There are several different types of memory errors, in which people may inaccurately recall details of events that did not occur, or they may simply misattribute the source of a memory. In other instances, imagination of a certain event can create confidence that such an event actually occurred. Causes of such memory errors may be due to certain cognitive factors, such as spreading activationSpreading activation
Spreading activation is a method for searching associative networks, neural networks, or semantic networks. The search process is initiated by labeling a set of source nodes with weights or "activation" and then iteratively propagating or "spreading" that activation out to other nodes linked to...
, or to physiological factors, including brain damage
Brain damage
"Brain damage" or "brain injury" is the destruction or degeneration of brain cells. Brain injuries occur due to a wide range of internal and external factors...
, age or emotional factors. Furthermore, memory errors have been reported in individuals with schizophrenia
Schizophrenia
Schizophrenia is a mental disorder characterized by a disintegration of thought processes and of emotional responsiveness. It most commonly manifests itself as auditory hallucinations, paranoid or bizarre delusions, or disorganized speech and thinking, and it is accompanied by significant social...
and depression
Depression (mood)
Depression is a state of low mood and aversion to activity that can affect a person's thoughts, behaviour, feelings and physical well-being. Depressed people may feel sad, anxious, empty, hopeless, helpless, worthless, guilty, irritable, or restless...
. The consequences of memory errors can have significant implications. Two main areas of concern regarding memory errors are in eyewitness testimony
Eyewitness testimony
Research in eyewitness testimony is mostly considered a subfield within legal psychology, however it is a field with very broad implications. Human reports are normally based on visual perception, which is generally held to be very reliable...
and cases of child abuse
Child abuse
Child abuse is the physical, sexual, emotional mistreatment, or neglect of a child. In the United States, the Centers for Disease Control and Prevention and the Department of Children And Families define child maltreatment as any act or series of acts of commission or omission by a parent or...
.
False memories
False memoriesFalse memory
False memory syndrome describes a condition in which a person's identity and relationships are affected by memories which are factually incorrect but are strongly believed. Peter J...
, sometimes referred to as confabulation
Confabulation
Confabulation is the process in which a memory is remembered falsely. Confabulations are indicative of a complicated and intricate process that can be led astray at any given point during encoding, storage, or recall of a memory. Two distinct types of confabulation are often distinguished...
, refer to the recollection of inaccurate details of an event, or recollection of a whole event that never occurred. Studies investigating this memory error have been able to successfully implant memories among participants that never existed, such as being lost in a mall as a child (termed the lost in the mall technique
Lost in the mall technique
The "Lost in the Mall" technique is an experimental procedure that was used to demonstrate that confabulations can be created through suggestions made to experimental subjects...
) or spilling a bowl of punch at a wedding reception. In this case, false memories were implanted among participants by their family members who claimed that the event had happened. This evidence demonstrates the possibility of implanting false memories on individuals by leading them to remember such events that never occurred. This memory error can be particularly worrisome in judicial settings, in which witnesses may have false recollections of a crime after it has happened, especially when told by others that particular things may have happened which did not. Another area of concern regarding false memories is in cases of child abuse. Some people believe therapists plant false memories into patients, leading them to believe that they have experienced abuse in their childhood even though they did not.
Misinformation effect
The misinformation effectMisinformation effect
The misinformation effect refers to the finding that exposure to misleading information presented between the encoding of an event and its subsequent recall causes impairment in memory. This effect occurs when participants' recall of an event they witnessed is altered by introducing misleading...
refers to the change in memory due to the presentation of information that is relevant to the target memory, such as leading questions or suggestions. Memories are likely to be altered when questions are worded differently or when inaccurate information is presented. For example, in one experiment participants watched a video of an automobile accident and were then asked questions regarding the accident. When asked how fast the automobiles were driving when they smashed into each other, the speed estimate was higher than when asked how fast the automobiles were driving when they hit, bumped or collided into each other. Similarly, participants were more likely to report there being shattered glass present when the word smashed was used instead of other verbs. Evidently, memory recollection can be altered with misleading information after the event.
Source confusion
Source confusion or unconscious transference, involves the misattribution of the source of a memory. For instance, an individual may recall seeing an event in person when in reality they only witnessed the event on television. Ultimately, the individual has an inability to remember the source of information in which the content and the source become dissociated. This may be more likely for more distant memories, such as childhood memories.Imagination inflation
Imagination inflation refers to when a person remembers details of a memory that are exaggerated versions of the actual event or remember an entire memory that never occurred due to the act of imaginationImagination
Imagination, also called the faculty of imagining, is the ability of forming mental images, sensations and concepts, in a moment when they are not perceived through sight, hearing or other senses...
. That is, when one imagines an event occurring, their confidence that this event actually did occur increases. One reason for this may be due to the act of imagination increasing the familiarity of the event. When the event seems more familiar, it may become more likely for people to report it actually occurring. For instance, in an experiment participants were asked to imagine playing inside and then running outside toward a window, falling and breaking it, while other participants did not imagine anything. Participants who had imagined this scenario reported an increased level of confidence that the event had actually happened in comparison to those who did not imagine the event. This error can be caused simply by imagining an event.
Deese–Roediger–McDermott (DRM) paradigm
Deese-Roediger-McDermott paradigmDeese–Roediger–McDermott paradigm
The Deese-Roediger-McDermott paradigm in cognitive psychology is an example of false memory.. The DRM Paradigm refers to the tendency to falsely recall a target word from a set list of words centered around that target word. This paradigm was first studied in 1959 and has been repeated in more...
refers to the incorrect recall of features of an event that were not actually present, due to the features being related to a common theme. This paradigm has been demonstrated with the use of word lists and subsequent recognition tests. For example, experiments have shown that if a research participant is presented with the words: bed rest awake tired dream wake snooze snore nap yawn drowsy, there is a high likelihood that the participant will falsely recall that the word sleep was in the list of words. These results show a significant illusion in memory, in which people remember items that were never presented simply due to their relation with other items in a common theme.
Schematic errors
Schematic errors refer to the use of a schemaSchema (psychology)
A schema , in psychology and cognitive science, describes any of several concepts including:* An organized pattern of thought or behavior.* A structured cluster of pre-conceived ideas....
to help reconstruct parts of an experience that cannot be remembered. This may include parts of the schema that did not actually take place, or aspects of a schema that are stereotypical of an event. Schemas can be described as mental guidelines (scripts) for events that are encountered in daily life. For example, when going to the gas station, there is a general pattern of how things will occur (i.e. turn car off, get out of car, open gas tank, punch the gas button, put nozzle into the tank, fill up the tank, put the nozzle back, close the tank, pay, turn car on, leave). Schemas make the world more predictable, allowing expectations to be formed of how things will enfold and to take note of things that happen out of context. However, schemas also allow for memory errors, in that if certain aspects of a scene or event are missing from memory, people may incorrectly remember having actually seen or experienced them due to the fact they are usually a regular aspect of the schema. For example, an individual may not remember paying the waiter, but may believe they have done so, as this is a regular step in the script of going to a restaurant. Similarly, a person may recall seeing a fridge in a picture of a kitchen, even if one was not actually depicted due to existing schemas which suggest that kitchens almost always contain a fridge.
Intrusion errors
Intrusion errors refer to when information that is related to the theme of a certain memory, but was not actually a part of the original episode, become associated with the event. This makes it difficult to distinguish which elements are in fact part of the original memory. One idea regarding how intrusion errors work is due to a lack of recall inhibition, which allows irrelevant information to be brought to awareness while attempting to remember. Another possible explanation is that intrusion errors result from a lack of new context integration into a viable memory trace, or into an already existing memory trace that is related to the appropriate memory. More explanations involve the temporal aspect of recall, meaning that as the time difference between the study periods of different lists approaches zero, the amount of intrusions between the lists tends to increase,the semantic aspect, meaning that the list of target words may have induced a false recall of non-target words that happen to have a similar or same meaning as the targets,and the similarity aspect, for example subjects who were given list of letters to recall were likely to replace target vowels with non-target vowels. Intrusion errors can be divided into two categories. The first are known as extra-list errors, which is when incorrect and non-related items are recalled, and were not part of the word study list. These types of intrusion errors often follow the DRM Paradigm effects, in which the incorrectly recalled items are often thematically related to the study list one is attempting to recall from. Another pattern for extra-list intrusions would be an acoustic similarity pattern, this pattern states that targets that have a similar sound to non-targets may be replaced with those non-targets in recall. One major type of extra-list intrusions is called the "Prior-List Intrusion" (PLI), a PLI occurs when targets from previously studied lists are recalled instead of the targets in the current list. PLIs often follow under the temporal aspect of intrusions in that since they were recalled recently they have a high chance of being recalled now. The second type of intrusion error is known as intra-list errors, which is similar to extra-list errors, except it refers to irrelevant recall for items that were on the word study list. Although these two categories of intrusion errors are based on word list studies in laboratories, the concepts can be extrapolated to real-life situations. Also, the same three factors that play a critical role in correct recall (recency, temporal association and semantic relatedness) play a role in intrusions as well. .Time-slice errors
Time-slice errors occur when a correct event is in fact recalled; however the event that was asked to be recalled is not the one that is recalled. In other words, the timing of events is incorrectly remembered. As discovered in a study by Brewer (1988), often the event or event details that are recalled occurred within a short time proximity to the memory required to be recalled. There are three possible theories as to why time-slice errors occur. First, they may be a form of interferenceInterference theory
-History:Bergström, a German psychologist, is credited as conducting the first study regarding interference in 1892. His experiment was similar to the Stroop task and required subjects to sort two decks of card with words into two piles. When the location was changed for the second pile, sorting...
, in which the memory information from one time impairs the recall of information from a different time. (see interference below). A second theory is that intrusion errors may be responsible, in that memories revolving around a similar time period thus share a common theme, and memories of various points of time within that larger time period become mixed with each other and intrude on each others’ recall. Last, the recall of memories often have holes due to forgotten details. Thus, individuals may be using a script (see schema errors) to help fill in these holes with general knowledge of what they know happened around this time. Since scripts are a time-based knowledge structure, which puts details of a memory in sequence to make it easier to understand, time-slice errors can occur if a detail is mistakenly placed in the wrong sequence.
Personal life effects
Personal life effects refer to the recall and belief in events as declared by family members or friends for having actually happened. Personal life effects are largely based on suggestive influences from external sources, such as family members or a therapist. Other influential sources may include media or literature stories which involve details that are believed to have been experienced or witnessed, such as a natural disaster close to where one resides, or a situation that is common and could have occurred, such as getting lost as a child. Personal life effects are most powerful when claimed to be true by a family member, and even more powerful when a secondary source confirms the event having happened. Personal life effects are believed to be a form of source confusion, in which the individual cannot recall where the memory is coming from Therefore, without being able to confirm the source of the memory, the individual may accept the false memory as true. Three factors may be responsible for the implantation of false autobiographical memoriesAutobiographical memory
Autobiographical memory is a memory system consisting of episodes recollected from an individual's life, based on a combination of episodic and semantic memory.-Formation:Conway and Pleydell-Pearce proposed that autobiographical...
. The first factor is time. As time passes, memories fade. Therefore, source confusion may result due to time delay. The second factor is the imagination inflation effect. As the amount of imagination increases, so does one’s familiarity for the contents of the imagination. Thus, source confusion may also occur due to the individual confusing the source of the memory for being true, when in fact it was imaginary. Lastly, social pressure to recall the memory may affect the individual’s belief in the false memory. For example, with increase in pressure, the individual may lower their criteria for validating a memory, and come to accept a false memory
False memory
False memory syndrome describes a condition in which a person's identity and relationships are affected by memories which are factually incorrect but are strongly believed. Peter J...
for being true. Personal life effects can be extremely crucial to recognize in cases of recovered memories
Recovered memory
Recovered memory is the description given to the apparent resurrection of the memory of events that had been forgotten or suppressed for a relatively long time. Retrograde amnesia secondary to physical or emotional trauma , or the suppression of painful memories from any cause, is an accepted concept...
, especially those of abuse, in which the individual may have been led to believe they had been abused as a child by a therapist during psychological therapy, when in fact they had not been. Personal life effects can also be important in witness testimonies, in which suggestions from authorities may incorrectly implant memories regarding witnesses a particular detail about a crime (see the Childhood Abuse and Eye Witness Testimony sections below).
Cognitive factors
Spreading activationOne theory on how memory works is through a concept called spreading activation. Spreading activation
Spreading activation
Spreading activation is a method for searching associative networks, neural networks, or semantic networks. The search process is initiated by labeling a set of source nodes with weights or "activation" and then iteratively propagating or "spreading" that activation out to other nodes linked to...
refers to the firing of connected nodes in associated memory links. The theory states that memory is organized in a theoretical web of associated ideas and related features. Each feature, or node, is connected to related features or ideas, which in turn are themselves connected to other related nodes. The theory of spreading activation states that, when you think about a specific idea/object, that node becomes activated and fires, causing the connections of related features to also become activated, to a lesser degree. This theory explains the theory of retrieval cues, in which a cue that is related to a target memory is used to help remember a certain memory.
Spreading activation can also demonstrate how memory errors may occur. As the network of memory associations increases in the number of connections–the connection density–the likelihood of memory gaps and errors occurring also increases. Put simply, the amount of activation a secondary connection receives depends on how many connections the initial node has associated with it. This is because the initial node must divide the amount of activation it spreads to related nodes by the number of connecting nodes it is associated with. If node 1 has three connecting nodes, and node 2 has 15 connecting nodes, the three connecting nodes from node 1 will receive greater activation levels (the activation level is divided less) than for the 15 connecting nodes from node 2, and the components of these nodes will be more easily brought to mind. What this means is that, with more connections a node has, the more difficulty there is bringing to mind one of its connecting features. This can lead to memory errors, in that if the connection density is so great that there is not enough activation reaching the secondary nodes, then the person may not recall a target memory that is actually present, and a memory error occurs.
Activation levels to secondary nodes is also determined by the strength of the association to the primary node. Some connections have greater association with the primary node (e.g. fire truck and fire or red, versus fire truck and hose or Dalmatian), and thus will receive a greater portion of the divided activation than less associated connections. Thus, associations that receive less activation will be out-competed by associations with stronger connections, and may fail to be brought into awareness, again causing a memory error.
Connection density
The connection densities, or neighbourhood densities of memory arrangements help distinguish which elements are a part of, or related to, the target memory. As the density of neural networks increases, the number of retrieval cues (associated nodes) also increases, which may allow for enhanced memory of the event. However, too many connections can inhibit memory in two ways. First, as described under the sub-section Spreading Activation, the total activation being spread from node 1 to connecting nodes is divided by the number of connections. With a greater number of connections, each connecting node receives less activation, which may result in too little activation for the memory cue to be brought to awareness. Connection strength, in which more strongly connected associations receive more activation than less-related associations, may also prevent specific connections from being brought to awareness due to being out-competed by the stronger associations. Second, with more connections branching from various other nodes, there is a greater probability of linking associated connections of different memories together (transplant errors) so that memory errors occur and incorrect features are recalled.
Retrieval cues
A retrieval cue is a type of hint that can be used to evoke a memory that has been stored but cannot be recalled. Retrieval cues work by selecting traces or associations in memory that contain specific content. With regards to the theory of spreading activation, retrieval cues use associated nodes to help activate a specific or target node. When no cues are available, recall is greatly reduced, leading to forgetting and possible memory errors. This is called retrieval failure, or cue-dependent forgetting
Cue-dependent forgetting
Cue-dependent forgetting, or retrieval failure, is the failure to recall a memory due to missing stimuli or cues that were present at the time the memory was encoded. It is one of five cognitive psychology theories of forgetting. It states that a memory is sometimes temporarily forgotten purely...
.
Retrieval cues can be divided into two subsets, although they are by no means used independent of each other. The first are called feature cues, in which information of the content of the original memory, or related content, is used to aid recall. The second category is context cues, in which information based on the specific context (environment) in which the memory or learning occurred is used to aid recall.
Although retrieval cues are usually helpful in helping to remember something, they can produce memory errors in three ways. First, incorrect cues can be used, leading to recall of an incorrect memory. Second, although the correct retrieval cues may be used, they may still produce an incorrect memory. This is likely to occur with high connection densities, in which the incorrect (but associated) node was activated and thus recalled, instead of the target memory. Third, the retrieval cue chosen may be correct and associated with the target memory, but it may not have a strong connection to the target memory, and thus may not produce enough activation to produce the target memory.
Encoding specificity
Encoding specificity
Encoding specificity principle
The encoding specificity principle provides a framework for understanding how contextual information affects memory and recall. The principle, proposed by researchers Thompson and Tulving, states that memory is most effective when information available at encoding is also present at retrieval...
is when retrieval is successful to the extent that the retrieval cues used to help recall, match the cues the individual used during learning or encoding. Memory errors due to encoding specificity means that the memory is likely not forgotten, however, the specific cues used during encoding the primary event are now unavailable to help remember the event. The cues used during encoding are dependent on the environment of the individual at the time the memory occurred. In context-dependent memory, recall is based on the difference between the encoding and recall environments. Recall for items learned in a particular context is better when recall occurs in the same place as when the initial memory occurred. This is why it is sometimes useful to “return to the scene of the crime” to help witnesses remember details of a crime, or for explaining why going to a specific location such as a residence or community setting, may lead to becoming flooded with memories of things that happened in that context. Recall can also depend on state-dependency, or the conditions of one's internal environment, at both the time of the event and of recall. For example, if intoxicated at the time the memory actually occurred, recall for details of the event is greater when recalling while intoxicated. Associated with state-dependency, recall can also depend on mood-dependency, in which recall is greater when the mood for when the memory occurred matches the mood during recall. These specific dependencies are based on the fact that the cues used during the initial event can be specific to the context or state one was in. In other words, various features of the environment (both internal and external) can be used to help encode the memory, and thus become retrieval cues. However, if the context or state changes at the time of recall, these cues may no longer be available, and thus recall is hindered.
Transfer-appropriate processing
Memory errors can also depend on the method of encoding used when initially experiencing or learning information, known as transfer-appropriate processing
Transfer-appropriate processing
Transfer-appropriate processing is a type of state-dependent memory specifically showing that memory performance is not only determined by the depth of processing , but by the relationship between how information is initially encoded and how it is later retrieved...
. Encoding processes can occur at three levels: visual form (the letters that make up a word), phonology (the sound of a word), and semantics (the meaning of the word or sentence). With relation to memory errors, the level of processing at the time of encoding and at the time of recall should be the same. Although semantic processing generally produces greater recall that shallower levels of processing, a study by Morris et al. demonstrated that what might be the key factor to greater recall is transfer-appropriate processing–when the level of processing at the original memory/learning time matches the level of processing used to help recall. In other words, if learning occurred by rhyming the target words to other words, then recall is best if testing is also at the phonological level of processing, such as a rhyming recognition test. Thus, memory errors can occur when the levels of processing between encoding and recall do not match.
Interference
Interference
Interference theory
-History:Bergström, a German psychologist, is credited as conducting the first study regarding interference in 1892. His experiment was similar to the Stroop task and required subjects to sort two decks of card with words into two piles. When the location was changed for the second pile, sorting...
occurs when specific information inhibits learning and /or recall for a specific memory. There are two forms of interference. First, proactive interference has to do with difficulty in learning new material based on the inability to override information from older memories. In such cases, retrieval cues continue to be associated and aimed at recalling previously learned information, affecting the recall of new material. Retroactive interference is the opposite of proactive interference, in which there is difficulty in the recall of previously learned information based on the interference of newly acquired information. In this case, retrieval cues are associated with the new information and not the older memory. thus affecting recall of older material. Interference of either form can produce memory errors, in which there is interference with the recall of material. In other words, previously used retrieval cues are no longer associated with prior memories, and thus memory confusion or even an inability to recall the memory can occur.
Physiological factors
Brain damageNeuroimaging
Neuroimaging
Neuroimaging includes the use of various techniques to either directly or indirectly image the structure, function/pharmacology of the brain...
studies have provided evidence for links between brain damage and memory errors. Brain areas implicated include the frontal lobe
Frontal lobe
The frontal lobe is an area in the brain of humans and other mammals, located at the front of each cerebral hemisphere and positioned anterior to the parietal lobe and superior and anterior to the temporal lobes...
and medial-temporal
Temporal lobe
The temporal lobe is a region of the cerebral cortex that is located beneath the Sylvian fissure on both cerebral hemispheres of the mammalian brain....
regions of the brain. Such damage may result in significant confabulation
Confabulation
Confabulation is the process in which a memory is remembered falsely. Confabulations are indicative of a complicated and intricate process that can be led astray at any given point during encoding, storage, or recall of a memory. Two distinct types of confabulation are often distinguished...
s and source confusion.
The prefrontal cortex
Prefrontal cortex
The prefrontal cortex is the anterior part of the frontal lobes of the brain, lying in front of the motor and premotor areas.This brain region has been implicated in planning complex cognitive behaviors, personality expression, decision making and moderating correct social behavior...
is in charge of making heuristic
Heuristic
Heuristic refers to experience-based techniques for problem solving, learning, and discovery. Heuristic methods are used to speed up the process of finding a satisfactory solution, where an exhaustive search is impractical...
judgments and systematic judgments, which involve analyzing the qualities of memories and the retrieval and evaluation of supporting or disconfirming information. Thus, if the frontal region is damaged, these abilities will be impaired and memories may not be retrieved or evaluated correctly. For example, one patient who suffered frontal lobe damage after an automobile accident reported memories of the support his family provided for him after the accident, which in reality, was false.
The temporal
Temporal lobe
The temporal lobe is a region of the cerebral cortex that is located beneath the Sylvian fissure on both cerebral hemispheres of the mammalian brain....
region of the brain contains the hippocampus
Hippocampus
The hippocampus is a major component of the brains of humans and other vertebrates. It belongs to the limbic system and plays important roles in the consolidation of information from short-term memory to long-term memory and spatial navigation. Humans and other mammals have two hippocampi, one in...
, which plays a significant role in memory
Memory
In psychology, memory is an organism's ability to store, retain, and recall information and experiences. Traditional studies of memory began in the fields of philosophy, including techniques of artificially enhancing memory....
. Thus, damage in this region may impair the function of this brain structure and result in memory problems.
Age
Studies have shown that the likelihood of memory errors occurring increases as age increases. Possible reasons for this are increased source confusion
Source of activation confusion model
SAC is a computational model of memory encoding and retrieval. It has been developed by Lynne M. Reder at Carnegie Mellon University. It shares many commonalities of with ACT-R.-Structure:...
for the event and findings that older persons have decreased levels of processing when first presented with new information. Source confusion refers to the inability to distinguish how one came upon different information. Older individuals can become confused with where they learnt information (e.g. TV, radio, newspaper, word of mouth, etc.), who presented them with the information (e.g. which of two experimenters presented them with facts and which presented them with irrelevant information), and whether the information came from an imagined source, and is thus not factual, or a real world source. This in itself is a form of memory error but can also create larger memory errors. When an older individual is confused whether the information is factual or was imagined they can begin to accept imagined memories as real and thus begin to rely on new false information. Levels of processing refers to the manner in which someone encodes information into their memory and how deeply it is encoded. There are three different levels of processing ranging from shallow to deep, deep being stored in long-term memory for a longer period and thus better remembered. The three levels are; visual form, being the shallowest form, phonology
Phonology
Phonology is, broadly speaking, the subdiscipline of linguistics concerned with the sounds of language. That is, it is the systematic use of sound to encode meaning in any spoken human language, or the field of linguistics studying this use...
, being a medium level of processing, and semantics
Semantics
Semantics is the study of meaning. It focuses on the relation between signifiers, such as words, phrases, signs and symbols, and what they stand for, their denotata....
(meaning), which is the deepest form of processing. The visual form of processing relies on the ability to see information and break it down into its components (e.g. see the word "dog", composed D, O, and G). Phonology relies on creating links to information through sound such as cues and tricks for memory (e.g. Dog rhymes with Fog). Finally, semantics refer to the creation of meaning behind information such as adding detail to allow the information to create links throughout our memory with other memories and thus be held in long-term memory for a longer period (e.g. A dog is a four-legged pet that often chases cats and chews on bones). Older individuals often begin to lose the quick ability to add meaning to new information, which leads to shallower processing and easier forgetting of the information gained. Both of these possible factors can decrease the validity of the memory due to retrieval for details of the event being more difficult to perform. This leads to details of memories being confused with others or lost completely, which lead to many errors in recall of a memory.
Emotion
The emotional impact of an event can have a direct impact on how the memory is first encoded, how it is later recalled, and what details of the event are accurately recalled. Highly emotional events tend to be recalled easily due to their emotional impact, as well as their distinctiveness relative to other memories (highly emotional events do not occur on a regular basis, and thus are easily separated from other events that are more commonly met). Emotional events may affect memory not only because of their distinctiveness, but also because of their arousal on the individual. Studies have found that prime or central features of such highly emotional events tend to be accurately recalled, whereas subtle details of the events are not remembered, or are remembered with vague consistency. Memory errors related to highly emotional events are influenced in ways such as:
• Whether the event was positive or negative in nature - The nature of the event can affect memory, negative events tend to be remembered with greater accuracy than positive events.
• Implicit theories of consistency and change - This term was coined by Ross (1989), and is used to describe the phenomena of memory change based on the belief of how the person felt at the time of the event compared to their current feelings about it. In other words, the memory of one's emotion towards an event can change depending on their current emotional state toward the same event. If a person believes their feelings at both times continue to be the same, then the current emotion to "remember" how they felt about the event at a previous time is used. If feelings are believed to have changed, then recall of the emotional involvement in the past event is adjusted to the current feelings.
• Intrusion errors - This term refers to the inclusion of details that may have been commonly experienced in the event, but not by the individual. For example, in the September 11 terrorist attacks, many people may state that they remember hearing about the attacks on the television news, as this was a common way of finding out this information, whereas they may have actually heard about it from a neighbour or on the radio.
• Mood-congruency - Items/events are better recalled when the mood of the individual at the time of the event and the time of recall are the same. Thus, if the mood at the time of recall does not match the mood experienced at the time the event occurred, there is an increased chance that complete recall will be affected/interrupted.
Memory errors in Abnormal Psychology
Abnormal psychologyAbnormal psychology
Abnormal psychology is the branch of psychology that studies unusual patterns of behavior, emotion and thought, which may or may not be understood as precipitating a mental disorder...
is the branch of psychology that studies unusual patterns of behavior, emotion and thought, which may or may not be understood as a mental disorder. Memory errors can commonly be found in types of abnormal psychology such as Alzheimer's Disease
Alzheimer's disease
Alzheimer's disease also known in medical literature as Alzheimer disease is the most common form of dementia. There is no cure for the disease, which worsens as it progresses, and eventually leads to death...
, depression
Depression (mood)
Depression is a state of low mood and aversion to activity that can affect a person's thoughts, behaviour, feelings and physical well-being. Depressed people may feel sad, anxious, empty, hopeless, helpless, worthless, guilty, irritable, or restless...
and schizophrenia
Schizophrenia
Schizophrenia is a mental disorder characterized by a disintegration of thought processes and of emotional responsiveness. It most commonly manifests itself as auditory hallucinations, paranoid or bizarre delusions, or disorganized speech and thinking, and it is accompanied by significant social...
.
Alzheimer's Disease
Alzheimer’s Disease is characterized by progressive memory impairment and decline, usually beginning short-term memory. As it is a progressive disease, Alzheimer’s usually begins with memory errors before proceeding to long-term memory stores. One form of memory error occurs in contrast to the theory of retrieval cues in being a reason for the occurrence of memory errors. As noted above, memory errors may be due to the lack of cues that can trigger a memory trace and bring it to awareness. However, studies have shown that the opposite may be true for patients with Alzheimer’s, such that cues may actually decrease perform onpriming
Priming (psychology)
Priming is an implicit memory effect in which exposure to a stimulus influences a response to a later stimulus. It can occur following perceptual, semantic, or conceptual stimulus repetition...
tasks. Patients also demonstrate errors known as misattribution errors, otherwise known as source confusion. However, studies show that these misattribution errors are dependent on whether the task is a familiarity or recollection tas. Although patients tend to exhibit a higher level of false recognitions than control groups. researchers have shown that they may exhibit less false-recognition early in the test due to familiarity being slower to develop. However, the observation of increasing instances of misattribution errors can be seen once familiarity does occur. This may be related to the retrieval cue speculation, in that familiar memories often contain cues we know, and thus may be the reason why familiarity can contribute to memory errors. Lastly, many studies have shown that Alzheimer’s patients commonly suffer from intrusion errors. Relative to the findings that retrieval cues may actually hurt recall performance, one study by Kramer et al. showed that intrusions are most commonly associated with cue-recall tasks. This study suggests that cues may lead to intrusions because patients may have a difficult time distinguishing between cues and distractions, which may help explain why cues increase memory errors in patients with Alzheimer’s. Since verbal intrusions are a common aspect of Alzheimer’s. some researchers believe that this characteristic may be helpful in the diagnosis of the disease.
Depression
Memory errors can occur in patients with depression or with depressive symptoms. Patients with depressive symptoms have a tendency to experience what is known as the negative triadCognitive therapy
Cognitive behavioral therapy is a psychotherapeutic approach: a talking therapy. CBT aims to solve problems concerning dysfunctional emotions, behaviors and cognitions through a goal-oriented, systematic procedure in the present...
, which is the perspective use of negative schemas and self-concepts to relate to the external world. Due to this negative triad, depressive patients have a tendency to have a much greater focus on, and recall for, negative details and events over positive ones. This may lead to memory errors related to the positive details of memories, impairing the accuracy or even complete recall of such memories. Depressed patients also experience deficits in psychomotor speed and in free recall of material both immediate and delayed. This suggests that material has been encoded but that patients are particularly impaired with regard to search and retrieval processes. Diverse aspects of memory such as short-term memory
Short-term memory
Short-term memory is the capacity for holding a small amount of information in mind in an active, readily available state for a short period of time. The duration of short-term memory is believed to be in the order of seconds. A commonly cited capacity is 7 ± 2 elements...
, long-term memory, semantic memory
Semantics
Semantics is the study of meaning. It focuses on the relation between signifiers, such as words, phrases, signs and symbols, and what they stand for, their denotata....
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...
, have been studied and linked to depression. Short-term memory, a temporary store for newly acquired information, seems to show no major impairments in the case of depressive patients who do seem to complain about poor concentration, which by itself can cause simple memory errors. Long-term memory, large capacity able to retain information over long periods of time, does however show impairment in the case of depressed individuals. They tend to have difficulties in recall and recognition for both verbal and visuo-spatial material with intervals of a few minutes or even hours creating complex memory errors in relation to speech and surrounding details. Individuals suffering with depression also showed a specific deficit in retrieving information meaningfully organized in their semantic memory, conceptual knowledge about the real world. Therefore, depressive patients can show memory errors for the most meaningful events in their lives, unable to recall these specific moments vividly like someone not suffering from depression might. In the case of implicit memory, when previous information influences ongoing responses, there has been little to no proof of a deficit in relations to depressed individuals.
Schizophrenia
Memory errors, specifically intrusion errors and imagination inflation effects, have been found to occur in patients diagnosed with schizophrenia. Intrusion errors can commonly be found in the recall portion of a memory test when a participant includes items that were not on the original list that was presented. These types of errors are linked to problems with self-monitoring, increased positive and disorganized symptoms (confusion within the brain), and poor executive functioning. Intrusion errors are found to be more likely in patients with positive schizophrenic symptomsDiagnosis of schizophrenia
The diagnosis of schizophrenia is based on criteria in either the American Psychiatric Association's Diagnostic and Statistical Manual of Mental Disorders, version DSM-IV-TR, or the World Health Organization's International Statistical Classification of Diseases and Related Health Problems, the...
, which involve an excess of normal bodily functions (e.g. delusions), versus negative schizophrenic symptoms
Diagnosis of schizophrenia
The diagnosis of schizophrenia is based on criteria in either the American Psychiatric Association's Diagnostic and Statistical Manual of Mental Disorders, version DSM-IV-TR, or the World Health Organization's International Statistical Classification of Diseases and Related Health Problems, the...
, which involve a decrease in normal bodily functions (e.g. refusal to speak). Possible reasons for this are reduced function in the central executive of the working memory, as well as defects in self-reflectivity, organization and reasoning. Self-reflectivity is the ability to recognize and reason about one’s own thought process, recognize that one has thoughts, and that those thoughts are one’s own and differentiate between cognitive operations. Self-reflectivity has been shown to be one of the biggest deficits faced by schizophrenics and data suggests that verbal memory intrusions are linked to deficits in the ability to identify, organize, and reason about one's own thoughts in patients with schizophrenia.
Imagination inflation effects were also common memory errors in patients with schizophrenia. This effect refers to events that individuals have imagined so vividly in their minds that this adds belief to the fact that the event truly occurred, although it did not. Possible reasons for this are increased source confusion and/or decreased source recollection of an event, which shows poor use of source-monitoring processes
Source-monitoring error
A source monitoring error is a type of memory error where a specific recollected experience is incorrectly determined to be the source of a memory. This error occurs when normal perceptual and reflective processes are disrupted, either by limited encoding of source information or by disruption to...
. Source-monitoring processes allow one to distinguish between a memory that we may believe has happened because it seems familiar and one that has truly occurred. In the case of schizophrenics, whose abilities to reason through their thoughts is impaired, something that they have imagined and thus, seems familiar can easily be mistaken for an actual event, especially in the case of quick heuristic processes
Heuristic
Heuristic refers to experience-based techniques for problem solving, learning, and discovery. Heuristic methods are used to speed up the process of finding a satisfactory solution, where an exhaustive search is impractical...
and snap judgments. Continuously imagining an action or event makes this action more and more familiar thus making it harder for a patient with schizophrenia to distinguish its source, questioning whether it is familiar because they have imagined it or if it is familiar because it happened. This leads to many memory errors for these individuals who are led to believe by their imagination of the event that it is real, has occurred and thus is stored in their memory for that reason.
Consequences of memory errors
Memory errors often lead to the belief of new memories, which are problematic. In the case of eyewitness testimony new false memories can often lead to wrong information and lack of conviction or wrongful conviction of individuals. Also in the case of child abuseChild abuse
Child abuse is the physical, sexual, emotional mistreatment, or neglect of a child. In the United States, the Centers for Disease Control and Prevention and the Department of Children And Families define child maltreatment as any act or series of acts of commission or omission by a parent or...
, memory errors can lead to the creation of false traumatic childhood memories, which can lead to false accusations and loss of trust.
Eyewitness testimony
Memory errors can occur in eyewitness testimonies due to a number of features commonly present in a trial, all of which may influence the authenticity of the memory, and may be detrimental to the outcome of the case at hand.Such features include:
• Leading questions – refers to how wording of questions can influence how an event is remembered. This can result from a misinformation effect
Misinformation effect
The misinformation effect refers to the finding that exposure to misleading information presented between the encoding of an event and its subsequent recall causes impairment in memory. This effect occurs when participants' recall of an event they witnessed is altered by introducing misleading...
or an imagination inflation effect. The misinformation effect occurs when information is presented after the events in question have occurred which leads to memory errors in later retrieval. Studies have suggested that witnesses may misattribute accuracy to misleading information because the sources of misleading information and witnessed information become confused. Misleading information can be acquired through reading of the newspaper, watching the news, being interviewed or when sitting in the courthouse during the trial. When witnesses are asked to recall specific details of an event they can begin to doubt their memory, which can cause memory errors. Misinformation can manifest itself as a memory leading the individual to believe it as true and witnesses may also begin to doubt their own memories of the event deciding instead that they must be wrong. Memory errors also occur through the imagination inflation effect. As stated earlier, the imagination inflation effect takes place when an individual imagines an event to the point where it is believed as a memory of an actual event. During trial, witnesses hear many different possible occurrences of events and are led to imagine these situations. Through imagining and rehearsal of the occurrences, witnesses may begin to see vividness and validity in the stories simply from rehearsal, not factual memories. This can create problems for witnesses when trying to distinguish between imagined events and the actual occurrence of the events. Small but largely significant details become easily mixed and these occurrences of memory errors can make or break a trial.
• Weapons Focus Effect
Weapon focus
Weapon focus is a factor affecting the reliability of eyewitness testimony. Weapon focus signifies a witness to a crime diverting his or her attention to the weapon the perpetrator is holding, thus leaving less attention for other details in the scene and leading to memory impairments later for...
–refers to the fact that witnesses are highly likely to pay close attention to the weapon being used during an event, which creates a reduction in the ability to remember other details regarding the crime. This can in turn create memory errors leaving the witness less able to remember details such as what the assailant was wearing or what distinctive features could be found on their body or face. One explanation for why witnesses tend to gravitate toward the weapon being used is said to be that the arousal of the witness is increased. When arousal becomes increased the number of perceptional cues being utilized by the brain decreases. This allows the individual to focus on the weapon cue and ignore other cues such as distinct scars or a bright red shirt. The weapons focus effect can also refer to how the report of the use of weapons in the case can influence the memory of the event, leading to a false memory of having heard a weapon being fired even if the witness did not. For example, if a newspaper reports that the victim was beaten with a hammer, upon reading this, the witness will begin to believe that a hammer was in fact used, even if they at no point saw a hammer. This can cause many memory errors and conflict of stories for witnesses. As a society we believe that newspapers or televised news reports have fact behind them. If they report the hammer being used, a witness might begin to second-guess their memory wondering if they missed the hammer or failed to remember that detail. Also, their story may become mixed with the media's representation of the story and the knife that they did see will be forgotten and instead be replaced with the hammer that was reported.
• Familiarity Effect
Exposure effect
The mere exposure effect is a psychological phenomenon by which people tend to develop a preference for things merely because they are familiar with them. In social psychology, this effect is sometimes called the familiarity principle...
–refers to the tendency of individuals to develop a preference for things simply because they are familiar. This can leave an individual to identify familiar people as guilty, even if they are not. When we are continuously exposed to the same object or person we begin to develop a positive attraction towards said object or person. Simply their familiarity creates a positive sense when re-exposed to the individual or object. In reality one can know very little about a person but by seeing them over and over again can gain unconscious positive recall for their face. This can create memory errors when individuals are asked to identify a criminal and someone familiar to them is placed in the line up. When a familiar face is in among the individuals that the witness is being asked to study, the witness will find himself or herself gravitating towards the familiar face whether or not this is who they witnessed committing the crime. This leaves them more likely to ignore the cues that are leading them towards other individuals and concentrate on the familiar face, resulting in a false accusation. The sense of familiarity can play a large role in the identification of criminals but when the familiarity of a criminal is mixed in with the familiarity of other individuals, choosing the right person can become quite difficult.
Child abuse
Memory errors regarding the recovery of repressed childhood abuse can occur due to post-event suggestions from a trusted source, such as a family member, or more commonly, a mental health professional. Due to possible relationships between childhood abuse and mental illnessMental illness
A mental disorder or mental illness is a psychological or behavioral pattern generally associated with subjective distress or disability that occurs in an individual, and which is not a part of normal development or culture. Such a disorder may consist of a combination of affective, behavioural,...
later in life, some mental health professionals believe in the Freudian theory of repressed memories as a defense mechanism for the anxiety that recall of the abuse would cause. Freud said that repression operates unconsciously in individuals who are not able to recall a threatening situation or may even forget that the abusive individual was ever part of their lives. Therefore, mental health professionals will sometimes seek to uncover possible instances of childhood abuse in patients, which may lead to suggestibility
Suggestibility
Suggestibility is the quality of being inclined to accept and act on the suggestions of others.A person experiencing intense emotions tends to be more receptive to ideas and therefore more suggestible. Generally, suggestibility decreases as age increases...
and cause a false memory
False memory
False memory syndrome describes a condition in which a person's identity and relationships are affected by memories which are factually incorrect but are strongly believed. Peter J...
of childhood abuse to arise, in an attempt to seek a cause to a mental illness No matter the confidence in the memory, this does not necessarily equate to the memory being true. This is an example of the misinformation effect
Misinformation effect
The misinformation effect refers to the finding that exposure to misleading information presented between the encoding of an event and its subsequent recall causes impairment in memory. This effect occurs when participants' recall of an event they witnessed is altered by introducing misleading...
and false memory effect. The fact that memories are not retrieved as whole entities but rather are reconstructed from information remaining in memory and other related knowledge make them easily susceptible to memory errors. This explains why working with mental health professionals and leading questions
Suggestibility
Suggestibility is the quality of being inclined to accept and act on the suggestions of others.A person experiencing intense emotions tends to be more receptive to ideas and therefore more suggestible. Generally, suggestibility decreases as age increases...
can sometimes manifest false memories by creating knowledge of possible events and asking individuals to focus on if these events actually took place Individuals begin to overthink these situations visualizing them in their mind and overanalyzing them. This in turn leads to the belief of situations and vivid memories. Patients are left with memories they believe are real and new events from their childhood which can lead to stress and trauma in their adult life and loss of relationships with those who are believed to be the abuser.