Eyewitness memory
Encyclopedia
Eyewitness memory refers to episodic memories that occur most frequently to the witness
of a crime or dramatic event. These witness testimonies
are highly relied upon in the judicial system. However, their validity is sometimes questioned due to the many influences that may take part in creating and maintaining these memories. Many experts have accumulated evidence suggesting that eyewitness memory is volatile . Eyewitness memories can be influenced by various components that occur during encoding and retrieval of the event.
It has long been speculated that mistaken eyewitness identification plays a major role in wrongful conviction of otherwise innocent individuals. A growing body of research now supports this, and some research indicates that mistaken eyewitness identification accounts for more convictions of the innocent than all other factors combined. The Innocence Project
determined that 75% of the 239 DNA exoneration cases had occurred from false eyewitness memory recognition. It is important to inform the public of these difficulties and flaws of eyewitness memory so that eyewitness accounts are not interpreted as the absolute truth.
s for traumatic events. It can only get more challenging when a person is experiencing a traumatic event. Since courts rely on eyewitness facial recognition, it is important to acknowledge that identification is not always accurate. Face-specific cognitive and neural processes show contributions to holistic processing and recognition in the episodic memories of eyewitnesses. Unreliability may be a result of mismatching between how faces are holistically processed and how composite systems retrieve features in faces during an event.
The other-race effect
(i.e. the own-race bias, cross-race effect, other-ethnicity effect, same-race advantage), which impacts facial recognition, proposes that a person better recognizes faces of his or her own race and shows less reliability in identifying other unfamiliar races, thus inhibiting encoding. The perceptual expertise account suggests that with an increase of exposure to one's own race, perceptual mechanisms develop allowing a person to be proficient at remembering their own race. The socio-cognitive
account predicts that motivational and/or attentional components over focus on the race of a person. Another hypothesis is that each race pays attention to certain facial details to differentiate between faces. However, other races might not encode these same features. A final suggestion is that faces of the same race are encoded more deeply, allowing a witness to have a more detailed memory; however, there has not been much research to support this hypothesis. Overall, the other race effect has focused on the African American and Caucasian races. Most research has shown white eyewitnesses to exhibit the other-race effect, but this effect extends to other races also. In general, memory is an individual process and that conceptualization of race causes racial ambiguity in facial recognition. Mono-racial eyewitnesses may depend on categorization more than multiracial eyewitnesses, who develop a more fluid concept of race. Perception may affect the immediate encoding of these unreliable notions due to prejudices, which can influence the speed of processing and classification of racially ambiguous targets. The ambiguity in eyewitness memory facial recognition can be attributed to the divergent strategies that are used when under the influence of racial bias.
in small amounts can aid memory, stress in higher amounts can hinder memory performance. Witnesses of a crime can even suffer from more severe implications, such as Post-Traumatic Stress Disorder
(PTSD) or even Psychogenic Amnesia
.
There is a negative correlation between individuals with PTSD and explicit memory
; the type of memory most commonly used in testimony. This may be due to individuals trying to suppress and forget the traumatic event that they were involved in, which is a common symptom of PTSD. There was however, a stronger positive correlation with PTSD and implicit memory
, than when compared to non-PTSD patients. That is, individuals suffering from PTSD had greater implicit memory than individuals not suffering from the disorder.
Psychogenic amnesia
can severely affect explicit memory. In the event that an individual witnessing of a crime is diagnosed with psychogenic amnesia, also known as dissociative amnesia, the individual will lose all memory of the traumatic event. These cases are most often associated with extremely violent crimes and/or murder.
In less severe cases, that is without a psychological diagnosis, memory is also affected. Results show that exposure to stress following recall, assists in activating the emotional memory that was involved during the event by 13.5%. Moreover, in cases such as the witnessing of a crime, the mood-congruency effect (mood congruence
) also comes into play. The mood-congruency effect occurs when an individual is retrieving memory while in the same mood-state as when learning occurred. Similar to context-dependent memory
, the mood congruency effect also improves memory, however it is achieved through internal mechanisms, instead of external. Biologically, moderate amounts of stress memory may also be improved by the release of corticosteroids. Conversely, too much stress, and therefore an extreme influx of corticosteroids can affect function of the hippocampus
and therefore hinder memory. Very high levels of corticosteroid release may even cause amnesia.
effect suggests that the presence of a weapon narrows a person’s attention, thus affecting eyewitness memory. A person focuses on the central detail (for example, the weapon) and loses focus on the peripheral details (for example, the perpetrator's characteristics). While the weapon is remembered clearly, the memories of the other details of the scene suffer. The weapon focus effect occurs because new items require more visual attention since they are not frequently processed. This focusing of attention takes away attention from peripheral details. For example, if a gun is brought into a school, it will attract a significant amount of attention because the students are not used to seeing this item. When participants watched a slide show and were asked to respond to novel stimuli, their reaction times were slower, regardless of whether the stimuli was dangerous, in comparison to reaction times for more frequent stimuli. When the item was dangerous (i.e. a weapon), participants had a lower accuracy and confidence than control groups. Another hypothesis is that a weapon causes an aroused state. In an aroused state, people focus on central details instead of peripheral ones.
. Individuals report what they believe to have witnessed at the time of the crime, even though this may be the result of a fabricated false memory. These effects can be a result of post event information. It is very important to provide witnesses with helpful response options on memory tests and to be warned of misleading influences that might affect how the memory of the event is recalled at a later time. Many employees, police force workers, and others are trained in post-warning, in order to reduce influences on the misinformation effect, which can be predicted before crime. In their studies, many researchers use eyewitnesses to study retrieval-blocking effects, which interfere with a witness’ ability to recall information. Misleading information prior to the event can also influence misinformation effects. However, retrieval-blocking methods can counteract misleading information in most cases. In addition, when eyewitnesses are given warning to avoid misinformation, more significant and accurate testimonies could be produced. Other studies also address how misinformation effect seems to amplify over increasing recall. Discussing events and being questioned multiple times may cause various versions of the testimonies. However, the earliest records prove to be most accurate due to a minimized misinformation effect.
procedure as well. The presentation of mug shot arrays alone does not seem to influence identification accuracy. However, this presentation can be influential if the police lineups include individuals who were earlier featured in the mug shot array. Individuals appearing in police lineups that also appeared in previous photo arrays may be identified as quickly as identifying the actual target. Therefore, in cases where a suspect is identified from mug shots following a line-up, it is uncertain whether the line-up identification is a result of the recognition of the perpetrator or of the detection of a person seen previously in mug shots.
is a method for an eyewitness to identify a perpetrator through a series of photos or a live arrangement of suspects. One outcome of a line up is an eyewitness can correctly identify the criminal. Another outcome is the eyewitness can correctly state that the criminal is not in the lineup. A third option is the eyewitness can fail to recognize that the culprit is present. Lastly, the eyewitness can incorrectly select another suspect. The ideal result is to correctly identify the offender and the worst outcome is to mistakenly identify an innocent.
presents a witness with a series of photos one at a time, requiring the participant to identify if each photo matches his/her memory before moving forward. The witness does not know how many photos are in the group. In a simultaneous lineup, the photos or suspects are viewed together. Sequential lineups produce fewer identifications, since they are more challenging, and require absolute judgment. This means that the decision regarding the matching of the memory to the photo is independently made. This is beneficial if the criminal is not in the lineup. On the other hand, a simultaneous lineup requires relative judgment, as the decision is not independent of the other possibilities. Police favor sequential lineups because there are fewer innocents falsely selected in this style of lineup. When a second lap of the suspects (a repeated viewing of a sequential lineup) is shown, more errors occur than when a single lap is shown. If a second lap is required, there are fewer errors than if the lap is chosen by a participant.
Confidence of the witness in his/her ability to make correct identification should not be used to assess the accuracy of identification. Witnesses should be asked to attempt identifications, even if their confidence declines. A witness’ confidence in his/her ability to retrieve an accurate identification preceding the actual identification task is not important to the accuracy of the subsequent judgment, as post-identification confidence is a better predictor.
In numerous experiments, after having given a judgement on the line-up test, witnesses are asked to evaluate their confidence in their choice. After analysis of post-judgment confidence accuracy, witnesses who were exceedingly confident in their identifications are only slightly more likely to be correct when compared to witnesses who exhibit little confidence in their decision.
A number of psychologists have investigated factors that might account for the confidence accuracy relationship.
The optimality hypothesis
states that factors which influence the optimality of information processing also influence the reliability of the confidence estimate. During situations in which information processing conditions are less than optimal (ex. the perpetrator is disguised as the exposure duration is brief) the witness is less precise on the identification test and demonstrates less dependable confidence estimate. The confidence accuracy correlation is thus estimated to be stronger in conditions that help optimal information processing, such as longer exposure time, and weaker under conditions that disable information processing.
Certain factors impact identification accuracy without influencing confidence, where as other factors influence confidence without having an effect on identification accuracy. For example, reconstructive processes in memory (i.e. the influence of post-event information on stored memories) can influence identification accuracy while not necessarily impacting confidence. Social influence processes (i.e. committing to a decision) might have an effect on confidence judgements while having little to no effect on the accuracy of the identification.
Although it was thought that confidence of a witness in identifying suspects was very important in the accuracy of identification, it is not. Accuracy in identification is situational and depends on the circumstances surrounding testimony, such as what is neighboring the crime and the identification procedures used. Nonetheless, the confidence of a witness during identification is generally a weak predictor of identification accuracy, as are the quality of descriptions and consistency between descriptions. These factors should not be taken into account when choosing whether or not to conduct a police line-up. When evaluating identification evidence, greater attention should be paid to the circumstances surrounding the identification, as the confidence of the eyewitness is less pertinent.
. For example, when participants were shown a video and instructed to answer all questions (answerable and unanswerable) about its content, they often fabricated information. Hypnosis is not an effective technique for retrieving inaccessible information because the amount of information reported would increase along with the amount of confabulation, possibly resulting in a false testimony.
technique, to elicit the most accurate eyewitness memory. In this preferred protocol for conducting interviews, the interrogator should make the witness feel comfortable, ask open-ended questions, and grant the witness freedom in describing the event. In addition, the interviewer should encourage the witness to exhaust his/her memory by reinstating the context of the event, recalling the events in different orders, and viewing the event scene from different perspectives.
. Misleading information offered by the investigators may attract more attention than the originally-encoded information, so the witness’ memory of the event is altered to include erroneous details suggested during the interview. In addition, repeating questions could make the witness feel pressured to change his or her answer or elaborate on an already-given response with fabricated details. Open-ended questioning can reduce the level of retrieval-enhanced suggestibility because the witness is not subjected to testing manipulation by the interviewer.
is a common technique used to help eyewitnesses remember details about a specific environment– reviewing the initial environment in which the original information was encoded. Taking a witness back to the scene where the event occurred, for example, will help facilitate the accuracy in identifying perpetrators. Reinstatement is thought to improve recall as it provides memory retrieval cues. Research has demonstrated that pairing faces of suspects or words with contextual cues at the scene of the crime will enhance performance on recognition tasks. Therefore, it seems practical that these results can be applied to eyewitness identification. Methods commonly used to examine context reinstatement include photographs of the environment/scene, mental contextual reinstatement cues, and guided recollection. Studies show that re-exposing participants to the crime scene does enhance performance in facial recognition. There were also notable effects for context reinstatement where improvement on correct identifications while increasing false alarms. Reports also show that the magnitude of improvement via context reinstatement increased in life-like situations compared to laboratory studies.
Studies on children show that the average child is at greater risk for memory loss, due to the brain’s immaturity and plasticity, when compared to an average adult. Poorer memory performance in young kids was shown when youth of different ages were asked to recall a doctor's visit. Children aged 3–5 answered with much less accuracy than individuals aged 6–15, indicating developmental differences in memory capacity. However, children often demonstrate high accuracy in remembering events that are personally meaningful, such as genital contact, which is prevalent in cases of sexual assault. Furthermore, it has been shown that information encoded and stored in memory is dependent on the extent of knowledge regarding the event. That is, if a child is exposed to an event that he or she knows little about, their memory of the event will not be as accurate when compared to a child who is more knowledgeable on event-related topics. These results of increased sensitivity, suggestibility and memory loss in children lead one to question the competency of a child to serve as an eyewitness. Researchers have determined that a child should be considered a competent witness if he or she has the capacity to observe, communicate, produce sufficient memories, differentiate truth from lies, and understand the obligation to tell the truth.
s. As a result, the most precise visual memories possible could only be the images that created the initial visual integration and not the stimulus array itself. Individuals who are said to possess eidetic memories
, may be of particular use in courtrooms when acting as an eyewitness, as they have the ability to hold to an image in mind for longer and with more accuracy than the average individual. This would be particularly useful at the time of a crime to retain images such as the perpetrator’s face, clothes, license plate, etc. These mental photographs may be comparable to presenting a real tangible photograph of the event witnessed. However, the memories of those who claim to have superior photographic memories are just as flawed as the memories of individuals who have normal mnemonic abilities
. This would affect the validity of testimonies from witnesses with photographic memories. Witnesses who believe that they are able to retrieve an accurate mental photograph will be much more confident in their account of the event and may influence the trial outcome. Accuracy recall of such visual scenes is a controversial issue. In the past, eidetikers were believed to have extremely accurate recall for visual displays, but modern research findings might reveal a different story. Some research demonstrates that eidetic children have greater recall accuracy for visual details compared to non-eidetic children. Other researchers have failed to find any advantage between the two groups. It is also hypothesized that eidetic imagery is not exactly related to memory and improves recall for visual details. If this is true, photographic memory is not particularly useful in the courtroom, which could explain the general failure to detect its existence in adults. Eidetikers cannot produce images of each and every sensory experience on demand. Alternatively, images are created only if the stimulus contains interesting material and a coherent structure. This characteristic critically reduces possible application to criminal justice. Even though there are various thoughts and ideas regarding photographic memory, some people do have exceptional memories, which will help improve the accuracy of eyewitness identification.
The frequency of eidetic imagery
is low in adults and shows greatest frequency in early child development. However it is almost non-existent past the age of 7. When procedures are used to classify eidetic memory separate from the characteristic of afterimage and memory image, a small number of children are classified as true eidetikers.
Witness
A witness is someone who has firsthand knowledge about an event, or in the criminal justice systems usually a crime, through his or her senses and can help certify important considerations about the crime or event. A witness who has seen the event first hand is known as an eyewitness...
of a crime or dramatic event. These witness testimonies
Testimony
In law and in religion, testimony is a solemn attestation as to the truth of a matter. All testimonies should be well thought out and truthful. It was the custom in Ancient Rome for the men to place their right hand on a Bible when taking an oath...
are highly relied upon in the judicial system. However, their validity is sometimes questioned due to the many influences that may take part in creating and maintaining these memories. Many experts have accumulated evidence suggesting that eyewitness memory is volatile . Eyewitness memories can be influenced by various components that occur during encoding and retrieval of the event.
It has long been speculated that mistaken eyewitness identification plays a major role in wrongful conviction of otherwise innocent individuals. A growing body of research now supports this, and some research indicates that mistaken eyewitness identification accounts for more convictions of the innocent than all other factors combined. The Innocence Project
Innocence Project
An Innocence Project is one of a number of non-profit legal organizations in the United States, Canada, the United Kingdom, Australia and New Zealand dedicated to proving the innocence of wrongly convicted people through the use of DNA testing, and to reforming the criminal justice systems to...
determined that 75% of the 239 DNA exoneration cases had occurred from false eyewitness memory recognition. It is important to inform the public of these difficulties and flaws of eyewitness memory so that eyewitness accounts are not interpreted as the absolute truth.
Challenges of Identifying Faces
People struggle to identify faces in person or from photos, a difficulty arising from the encoding of faces. When participants were given a basic memory test from an array of photos or a lineup, they struggled to accurately identify the images and had low recognition. This is a starting point to compare with eyewitness identificationEyewitness identification
Eyewitness identification, in criminal law, is evidence received from a witness "who has actually seen an event and can so testify in court"....
s for traumatic events. It can only get more challenging when a person is experiencing a traumatic event. Since courts rely on eyewitness facial recognition, it is important to acknowledge that identification is not always accurate. Face-specific cognitive and neural processes show contributions to holistic processing and recognition in the episodic memories of eyewitnesses. Unreliability may be a result of mismatching between how faces are holistically processed and how composite systems retrieve features in faces during an event.
The other-race effect
Cross-race effect
Cross-race effect is the tendency for people of one race to have difficulty recognizing and processing faces and facial expressions of members of a race or ethnic group other than their own....
(i.e. the own-race bias, cross-race effect, other-ethnicity effect, same-race advantage), which impacts facial recognition, proposes that a person better recognizes faces of his or her own race and shows less reliability in identifying other unfamiliar races, thus inhibiting encoding. The perceptual expertise account suggests that with an increase of exposure to one's own race, perceptual mechanisms develop allowing a person to be proficient at remembering their own race. The socio-cognitive
Socio-cognitive
Socio-cognitive or sociocognitive describes integrated cognitive and social properties of systems, processes, functions, models, as well as can indicate the branch of science, engineering or technology, such as socio-cognitive research, socio-cognitive interactions.This term is especially used when...
account predicts that motivational and/or attentional components over focus on the race of a person. Another hypothesis is that each race pays attention to certain facial details to differentiate between faces. However, other races might not encode these same features. A final suggestion is that faces of the same race are encoded more deeply, allowing a witness to have a more detailed memory; however, there has not been much research to support this hypothesis. Overall, the other race effect has focused on the African American and Caucasian races. Most research has shown white eyewitnesses to exhibit the other-race effect, but this effect extends to other races also. In general, memory is an individual process and that conceptualization of race causes racial ambiguity in facial recognition. Mono-racial eyewitnesses may depend on categorization more than multiracial eyewitnesses, who develop a more fluid concept of race. Perception may affect the immediate encoding of these unreliable notions due to prejudices, which can influence the speed of processing and classification of racially ambiguous targets. The ambiguity in eyewitness memory facial recognition can be attributed to the divergent strategies that are used when under the influence of racial bias.
Stress and Trauma
Stress or trauma during an event affects encoding of that memory, leading to one of three results. Trauma may cause automatic repression of the event out of consciousness. The inability to access the memory occurs in many instances involving the recovery of child abuse memories. Another result could be that the person involved in the event experiences dissociation, in which he or she pretends to be somewhere else while the trauma is taking place, as a coping mechanism. Lastly, trauma induces a flashbulb effect, in which the witness vividly remembers the significant details of the event. The mental state of an individual both during a crime and during testimony can affect the success of memory retrieval. Although stress and arousalArousal
Arousal is a physiological and psychological state of being awake or reactive to stimuli. It involves the activation of the reticular activating system in the brain stem, the autonomic nervous system and the endocrine system, leading to increased heart rate and blood pressure and a condition of...
in small amounts can aid memory, stress in higher amounts can hinder memory performance. Witnesses of a crime can even suffer from more severe implications, such as Post-Traumatic Stress Disorder
Post-traumatic stress disorder
Posttraumaticstress disorder is a severe anxiety disorder that can develop after exposure to any event that results in psychological trauma. This event may involve the threat of death to oneself or to someone else, or to one's own or someone else's physical, sexual, or psychological integrity,...
(PTSD) or even Psychogenic Amnesia
Psychogenic amnesia
Psychogenic amnesia, also known as functional amnesia or dissociative amnesia, is a memory disorder characterized by extreme memory loss that is caused by extensive psychological stress and that cannot be attributed to a known neurobiological cause...
.
Post Traumatic Stress Disorder
There is a negative correlation between individuals with PTSD and explicit memory
Explicit memory
Explicit memory is the conscious, intentional recollection of previous experiences and information. People use explicit memory throughout the day, such as remembering the time of an appointment or recollecting an event from years ago....
; the type of memory most commonly used in testimony. This may be due to individuals trying to suppress and forget the traumatic event that they were involved in, which is a common symptom of PTSD. There was however, a stronger positive correlation with PTSD 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...
, than when compared to non-PTSD patients. That is, individuals suffering from PTSD had greater implicit memory than individuals not suffering from the disorder.
Psychogenic Amnesia
Psychogenic amnesia
Psychogenic amnesia
Psychogenic amnesia, also known as functional amnesia or dissociative amnesia, is a memory disorder characterized by extreme memory loss that is caused by extensive psychological stress and that cannot be attributed to a known neurobiological cause...
can severely affect explicit memory. In the event that an individual witnessing of a crime is diagnosed with psychogenic amnesia, also known as dissociative amnesia, the individual will lose all memory of the traumatic event. These cases are most often associated with extremely violent crimes and/or murder.
Mood-Congruency Effect
In less severe cases, that is without a psychological diagnosis, memory is also affected. Results show that exposure to stress following recall, assists in activating the emotional memory that was involved during the event by 13.5%. Moreover, in cases such as the witnessing of a crime, the mood-congruency effect (mood congruence
Mood congruence
In psychiatry, mood congruence is the congruence between feeling, or the emotion that a person is experiencing, and affect display, or the manner in which that emotion is "presenting", or being expressed....
) also comes into play. The mood-congruency effect occurs when an individual is retrieving memory while in the same mood-state as when learning occurred. Similar to context-dependent memory
Context-dependent memory
Context-dependent memory refers to improved recall of specific episodes or information when the context present at encoding and retrieval are the same. One particularly common example of context-dependence at work occurs when an individual has lost an item in an unknown location...
, the mood congruency effect also improves memory, however it is achieved through internal mechanisms, instead of external. Biologically, moderate amounts of stress memory may also be improved by the release of corticosteroids. Conversely, too much stress, and therefore an extreme influx of corticosteroids can affect function of 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...
and therefore hinder memory. Very high levels of corticosteroid release may even cause amnesia.
Weapon Focus
The weapon focusWeapon 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...
effect suggests that the presence of a weapon narrows a person’s attention, thus affecting eyewitness memory. A person focuses on the central detail (for example, the weapon) and loses focus on the peripheral details (for example, the perpetrator's characteristics). While the weapon is remembered clearly, the memories of the other details of the scene suffer. The weapon focus effect occurs because new items require more visual attention since they are not frequently processed. This focusing of attention takes away attention from peripheral details. For example, if a gun is brought into a school, it will attract a significant amount of attention because the students are not used to seeing this item. When participants watched a slide show and were asked to respond to novel stimuli, their reaction times were slower, regardless of whether the stimuli was dangerous, in comparison to reaction times for more frequent stimuli. When the item was dangerous (i.e. a weapon), participants had a lower accuracy and confidence than control groups. Another hypothesis is that a weapon causes an aroused state. In an aroused state, people focus on central details instead of peripheral ones.
Interference
The testimony of a witness can lose validity due to many external stimuli that may affect what was witnessed during the crime, and therefore obstruct memory. For example, if an individual witnesses a car accident on a very public street, there may be too many cues distracting the witness from the main focus. So many interfering stimulus inputs may have suppressed the importance of the stimulus of focus, the accident. This can cause memory traces for the event to degrade and the representations for those memories may diminish. This is known as the cue-overload principle.Misinformation Effect
Witnesses can be subject to memory distortions that can alter their account of events. It is of particular interest that the memory of an eyewitness can become compromised by other information, such that an individual's memory becomes biased. This can increase Eyewitnesses' sensitivity to 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...
. Individuals report what they believe to have witnessed at the time of the crime, even though this may be the result of a fabricated false memory. These effects can be a result of post event information. It is very important to provide witnesses with helpful response options on memory tests and to be warned of misleading influences that might affect how the memory of the event is recalled at a later time. Many employees, police force workers, and others are trained in post-warning, in order to reduce influences on the misinformation effect, which can be predicted before crime. In their studies, many researchers use eyewitnesses to study retrieval-blocking effects, which interfere with a witness’ ability to recall information. Misleading information prior to the event can also influence misinformation effects. However, retrieval-blocking methods can counteract misleading information in most cases. In addition, when eyewitnesses are given warning to avoid misinformation, more significant and accurate testimonies could be produced. Other studies also address how misinformation effect seems to amplify over increasing recall. Discussing events and being questioned multiple times may cause various versions of the testimonies. However, the earliest records prove to be most accurate due to a minimized misinformation effect.
Unconscious Transference
Many mistaken identifications are the result of unconscious transference, or the inability to distinguish between the perpetrator and another person who was encountered in a different context . In many of these cases, the culprit is confused with a different person present at the crime scene. Implicit processing takes place during the event, in which the witness encodes the general features of innocent bystanders, creating a sense of familiarity. At retrieval, this familiarity could cause people who were merely present in the crime scene to be confused with the culprit. After viewing a video of a crime involving a thief and two innocent bystanders, participants were asked to identify the perpetrator from a lineup including the three confederates present in the video and three other people never before encountered. Most participants falsely identified an innocent person from the lineup. Furthermore, participants were more likely to misidentify one of the two innocent confederates in the video than one of the three unfamiliar people. Unconscious transference occurs in this instance when the witness misattributes his or her sense of familiarity of the perpetrator to a bystander. This confusing effect of familiarity is found in the mug shotMug shot
A mug shot, mugshot or booking photograph, is a photographic portrait taken after one is arrested. The purpose of the mug shot is to allow law enforcement to have a photographic record of the arrested individual to allow for identification by victims and investigators. Most mug shots are two-part,...
procedure as well. The presentation of mug shot arrays alone does not seem to influence identification accuracy. However, this presentation can be influential if the police lineups include individuals who were earlier featured in the mug shot array. Individuals appearing in police lineups that also appeared in previous photo arrays may be identified as quickly as identifying the actual target. Therefore, in cases where a suspect is identified from mug shots following a line-up, it is uncertain whether the line-up identification is a result of the recognition of the perpetrator or of the detection of a person seen previously in mug shots.
Lineups:
A police lineupPolice lineup
A police lineup or identity parade is a process by which a crime victim or witness's putative identification of a suspect is confirmed to a level that can count as evidence at trial....
is a method for an eyewitness to identify a perpetrator through a series of photos or a live arrangement of suspects. One outcome of a line up is an eyewitness can correctly identify the criminal. Another outcome is the eyewitness can correctly state that the criminal is not in the lineup. A third option is the eyewitness can fail to recognize that the culprit is present. Lastly, the eyewitness can incorrectly select another suspect. The ideal result is to correctly identify the offender and the worst outcome is to mistakenly identify an innocent.
Police Role in Lineup
There are specific guidelines for police to follow when administering a lineup to reduce the bias of a lineup and increase the accuracy. Police must reduce the pressure that eyewitnesses feel to select a criminal from an array of photos or persons. They should make sure that the eyewitness is aware that the perpetrator might not be in the lineup. Also, police should conduct a double blind procedure that does not allow them to see the line up. Thus, they cannot subject the eyewitness to any of their suspicions as to who the suspect is. This also prevents the police from soliciting any feedback to the eyewitness. Feedback can produce a false confidence in the witness’ selection. When overseeing a lineup, the police can also use speed of recognition to determine the validity of the identification. If the witness quickly identifies the perpetrator, then the selection is more likely to be correct.Style of Lineup
A sequential lineupSequential Lineups
Sequential Lineups is one of the two lineup methods used for eyewitnesses to identify criminals in police station. In a standard sequential lineup, the suspects or their photos are presented one at a time to the witnesses for only once...
presents a witness with a series of photos one at a time, requiring the participant to identify if each photo matches his/her memory before moving forward. The witness does not know how many photos are in the group. In a simultaneous lineup, the photos or suspects are viewed together. Sequential lineups produce fewer identifications, since they are more challenging, and require absolute judgment. This means that the decision regarding the matching of the memory to the photo is independently made. This is beneficial if the criminal is not in the lineup. On the other hand, a simultaneous lineup requires relative judgment, as the decision is not independent of the other possibilities. Police favor sequential lineups because there are fewer innocents falsely selected in this style of lineup. When a second lap of the suspects (a repeated viewing of a sequential lineup) is shown, more errors occur than when a single lap is shown. If a second lap is required, there are fewer errors than if the lap is chosen by a participant.
Size of Lineup
Lineups should have diverse characteristics and should not be biased toward or against the suspect. If the appearance of a person stands out amongst the otherwise undistinctive crowd then an eyewitness is more likely to select that person regardless of their own recollection of the criminal. Thus, this line up is suggestive. Fillers should be added to the lineup in order to depict a broad spectrum of characteristics. This will make it more difficult for the eyewitness; however, if they are sure of a suspect, it is usually a more accurate choice. Increasing the nominal size of a lineup (the actual number of suspects that are compiled) often decreases the potential for a wrong selection. Functional size also plays a role in lineup bias. Effective size is the number of probable suspects. Police use these three numbers to evaluate a lineup.Viewpoints
Many studies, as well as police procedures, are dependent on photo lineups or police lineups where the eyewitness views the suspects from a distance. This procedure is done in an attempt to eliminate suspects and identify the perpetrator. These types of lineups allow only small degrees of visual information for the eyewitness, such as limited viewing angles which would restrict the level of detail, compared to a computerized virtual line-up where witnesses can see the targets from multiple angles and distances. One might anticipate that examination of the suspects from unlimited viewpoints would allow for better recognition cues, then when compared to limited views. However, unlimited visual information may be disadvantageous and counterproductive if the information offered at the time of retrieval was not actually present at the time of memory encoding. For example, if an eyewitness only saw the face of the perpetrator from one angle, seeing the lineup participants from other viewpoints might be distracting. Other studies have demonstrated that unlimited viewpoints do improve accuracy in police lineups. It should also be noted that the eyewitness accuracy improves when the distance between the suspect and witness matches the distance during the initial witnessing of the crime.Retroactive Interference
Another phenomena that may interfere with an eyewitness’ memory is retroactive interference. This occurs when new information is processed and can therefore obstruct old information. A common interference that may occur after the event of a crime is the reporting of the crime. Police investigations include questioning, and make suggestions. The processing of new information may disrupt or entirely replace old information, thus losing it. If a police officer has a reason to believe that a suspect is guilty, the interrogator's bias can influence the eyewitness's memory and selection. Also, the interrogators can put pressure on witnesses' causing them to want to select a perpetrator from the lineup. Oftentimes, eyewitnesses are unsuspecting of interrogator bias and believe their memories to be uncontaminated.Co-witness Contamination
Oftentimes, the presence of a co-witness can contaminate memories. When witnesses confer about an event, it can become jumbled and they agree on an incorrect narrative. Researchers found that 71% of witnesses conformed their eyewitness accounts to include false components that their co-witnesses remembered.This makes it very difficult to reconstruct the actual account of the event. To prevent this effect, police should separate witnesses as early as possible before the reporting of the event. Unfortunately, this is difficult, especially if the police become involved after time has passed. Police should inform witnesses of the possibility of contamination as soon as possible. Witnesses should be interviewed as soon as possible with police noting if the witnesses have compared accounts. Once the accounts have been recorded, police should make notes of similarities, which could point to contaminated details or facts.Confidence
As a witness identifies a perpetrator, the identification can be made with a particular degree of confidence. This may cause significant individual differences between witnesses. There are two types of confidence: confidence in a witness’ own ability to make an identification (prior to viewing a police line up) and confidence in having made an accurate identification or accurate rejection.Confidence of the witness in his/her ability to make correct identification should not be used to assess the accuracy of identification. Witnesses should be asked to attempt identifications, even if their confidence declines. A witness’ confidence in his/her ability to retrieve an accurate identification preceding the actual identification task is not important to the accuracy of the subsequent judgment, as post-identification confidence is a better predictor.
In numerous experiments, after having given a judgement on the line-up test, witnesses are asked to evaluate their confidence in their choice. After analysis of post-judgment confidence accuracy, witnesses who were exceedingly confident in their identifications are only slightly more likely to be correct when compared to witnesses who exhibit little confidence in their decision.
A number of psychologists have investigated factors that might account for the confidence accuracy relationship.
The optimality hypothesis
Optimality theory
Optimality theory is a linguistic model proposing that the observed forms of language arise from the interaction between conflicting constraints. OT models grammars as systems that provide mappings from inputs to outputs; typically, the inputs are conceived of as underlying representations, and...
states that factors which influence the optimality of information processing also influence the reliability of the confidence estimate. During situations in which information processing conditions are less than optimal (ex. the perpetrator is disguised as the exposure duration is brief) the witness is less precise on the identification test and demonstrates less dependable confidence estimate. The confidence accuracy correlation is thus estimated to be stronger in conditions that help optimal information processing, such as longer exposure time, and weaker under conditions that disable information processing.
Certain factors impact identification accuracy without influencing confidence, where as other factors influence confidence without having an effect on identification accuracy. For example, reconstructive processes in memory (i.e. the influence of post-event information on stored memories) can influence identification accuracy while not necessarily impacting confidence. Social influence processes (i.e. committing to a decision) might have an effect on confidence judgements while having little to no effect on the accuracy of the identification.
Although it was thought that confidence of a witness in identifying suspects was very important in the accuracy of identification, it is not. Accuracy in identification is situational and depends on the circumstances surrounding testimony, such as what is neighboring the crime and the identification procedures used. Nonetheless, the confidence of a witness during identification is generally a weak predictor of identification accuracy, as are the quality of descriptions and consistency between descriptions. These factors should not be taken into account when choosing whether or not to conduct a police line-up. When evaluating identification evidence, greater attention should be paid to the circumstances surrounding the identification, as the confidence of the eyewitness is less pertinent.
Interviews:
The method of conducting an interview has great implication on the accuracy of the testimony. When the person being interviewed is forced to provide more information, he/she is more likely to engage in confabulationConfabulation
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...
. For example, when participants were shown a video and instructed to answer all questions (answerable and unanswerable) about its content, they often fabricated information. Hypnosis is not an effective technique for retrieving inaccessible information because the amount of information reported would increase along with the amount of confabulation, possibly resulting in a false testimony.
Cognitive Interview Technique
Researchers have developed a strategy, entitled the cognitive interviewCognitive interview
The cognitive interview is a method of interviewing in which eyewitnesses and victims report what they remember from a crime scene. Using four retrievals, the primary focus of the cognitive interview is to make witnesses and victims of a situation aware of all the events that transpired...
technique, to elicit the most accurate eyewitness memory. In this preferred protocol for conducting interviews, the interrogator should make the witness feel comfortable, ask open-ended questions, and grant the witness freedom in describing the event. In addition, the interviewer should encourage the witness to exhaust his/her memory by reinstating the context of the event, recalling the events in different orders, and viewing the event scene from different perspectives.
Suggestibility
Distortions in a witness’s memory can be induced by suggestive questioning procedures . Asking eyewitnesses to repeatedly retrieve information in multiple interviews may enhance memory because the event is being rehearsed many times or, as in many cases, increase suggestibilitySuggestibility
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...
. Misleading information offered by the investigators may attract more attention than the originally-encoded information, so the witness’ memory of the event is altered to include erroneous details suggested during the interview. In addition, repeating questions could make the witness feel pressured to change his or her answer or elaborate on an already-given response with fabricated details. Open-ended questioning can reduce the level of retrieval-enhanced suggestibility because the witness is not subjected to testing manipulation by the interviewer.
Contextual Reinstatement
Contextual reinstatementContext-dependent memory
Context-dependent memory refers to improved recall of specific episodes or information when the context present at encoding and retrieval are the same. One particularly common example of context-dependence at work occurs when an individual has lost an item in an unknown location...
is a common technique used to help eyewitnesses remember details about a specific environment– reviewing the initial environment in which the original information was encoded. Taking a witness back to the scene where the event occurred, for example, will help facilitate the accuracy in identifying perpetrators. Reinstatement is thought to improve recall as it provides memory retrieval cues. Research has demonstrated that pairing faces of suspects or words with contextual cues at the scene of the crime will enhance performance on recognition tasks. Therefore, it seems practical that these results can be applied to eyewitness identification. Methods commonly used to examine context reinstatement include photographs of the environment/scene, mental contextual reinstatement cues, and guided recollection. Studies show that re-exposing participants to the crime scene does enhance performance in facial recognition. There were also notable effects for context reinstatement where improvement on correct identifications while increasing false alarms. Reports also show that the magnitude of improvement via context reinstatement increased in life-like situations compared to laboratory studies.
Experimental Context
An alteration of context was found to be one of the most important predictors of recognition accuracy. Such changes in experimental context have been shown to have effects similar to transformations in appearance, such as disguises. Criminal identifications can be influenced by a change in context. Investigators must account for the fact that encountering an acquaintance that we usually see in one context, such as work place, alters memory generalizability when compared to encountering the same acquaintance in another environment that acts like an unassociated context, such as a grocery store. The changes in environment make it difficult to identify this acquaintance. Initially, the individual might seem familiar but because this person is not in the normal context, it might be difficult to place the face and recall the name. Researchers have begun to implement procedures for reinstating the context surrounding a specific event in an attempt to improve identification accuracy. Reinstating the crime scene is often not possible sometimes, however it is possible to have eyewitnesses imagine and thus mentally reinstate the surroundings with imagery instructions and other mnemonic devices. In some instances, objects from the crime scene such as guns or clothing can be used additionally to help reinstate the context. Such methods have successfully shown to improve reliability and accuracy of eyewitness recall.Child Testimony
Children's testimony refers to when children are required to testify in court after witnessing or being involved in a crime. In situations where a child is the main witness of a crime, the result of the hearing is dependent on his or her memory of the event. Factors that would influence the testimony include how well a child can identify the individuals involved, the setting of the crime, and the accuracy of their explanation. Children can also be involved in testimony not only when they are witnesses, but also when they are victims. Due to the sensitivity of these cases, strategic interviewing is implemented for children, which may result in the validity of the memory to suffer. Strategic interviewing must be assessed with sensitivity on an individual bases and without leading questions, as they may influence the child’s answer. Additional influences may include individuals surrounding the child prior to, and during the hearing. If children hear new information from such individuals, studies show that children will more than likely agree with what the others said – regardless of the child’s initial opinion.Studies on children show that the average child is at greater risk for memory loss, due to the brain’s immaturity and plasticity, when compared to an average adult. Poorer memory performance in young kids was shown when youth of different ages were asked to recall a doctor's visit. Children aged 3–5 answered with much less accuracy than individuals aged 6–15, indicating developmental differences in memory capacity. However, children often demonstrate high accuracy in remembering events that are personally meaningful, such as genital contact, which is prevalent in cases of sexual assault. Furthermore, it has been shown that information encoded and stored in memory is dependent on the extent of knowledge regarding the event. That is, if a child is exposed to an event that he or she knows little about, their memory of the event will not be as accurate when compared to a child who is more knowledgeable on event-related topics. These results of increased sensitivity, suggestibility and memory loss in children lead one to question the competency of a child to serve as an eyewitness. Researchers have determined that a child should be considered a competent witness if he or she has the capacity to observe, communicate, produce sufficient memories, differentiate truth from lies, and understand the obligation to tell the truth.
Intellectual Ability and Testimony
Individuals with intellectual disabilities are at a higher risk for sexual abuse and exploitation because they are often dependent on others and uneducated or physically incompetent in ways of self-protection. Therefore, much research has been devoted to investigating the accountability of these individuals in eyewitness testimonies. When a group of adults chosen by the Developmental Disabilities Association was compared to a control group of college students, they performed equally well when identifying the perpetrator from a lineup. However, the disabled individuals were much worse at recognizing when a target was absent from a lineup, leading to the determination that people with intellectual disabilities are more suggestible and likely to confabulate. Children with intellectual disabilities show similar patterns in their eyewitness accounts. After watching a video of a crime, children with these disabilities performed worse than non-disabled kids of the same age on free recall, open-ended questions, and both general and specific misleading questions. These children performed better than the age-matched control group only on leading questions with yes or no answers, suggesting that they are more likely to acquiesce in the interview. These findings indicate that individuals with intellectual disabilities could be considered competent witnesses if interrogated in a non-leading manner.Photographic Memory (Eidetic Memory)
Perception and knowledge of the world stem and expand from the selection and integration of stimuli hitting our sensory receptorSensory receptor
In a sensory system, a sensory receptor is a sensory nerve ending that responds to a stimulus in the internal or external environment of an organism...
s. As a result, the most precise visual memories possible could only be the images that created the initial visual integration and not the stimulus array itself. Individuals who are said to possess eidetic memories
Eidetic memory
Eidetic , commonly referred to as photographic memory, is a medical term, popularly defined as the ability to recall images, sounds, or objects in memory with extreme precision and in abundant volume. The word eidetic, referring to extraordinarily detailed and vivid recall not limited to, but...
, may be of particular use in courtrooms when acting as an eyewitness, as they have the ability to hold to an image in mind for longer and with more accuracy than the average individual. This would be particularly useful at the time of a crime to retain images such as the perpetrator’s face, clothes, license plate, etc. These mental photographs may be comparable to presenting a real tangible photograph of the event witnessed. However, the memories of those who claim to have superior photographic memories are just as flawed as the memories of individuals who have normal mnemonic abilities
Mnemonic
A mnemonic , or mnemonic device, is any learning technique that aids memory. To improve long term memory, mnemonic systems are used to make memorization easier. Commonly encountered mnemonics are often verbal, such as a very short poem or a special word used to help a person remember something,...
. This would affect the validity of testimonies from witnesses with photographic memories. Witnesses who believe that they are able to retrieve an accurate mental photograph will be much more confident in their account of the event and may influence the trial outcome. Accuracy recall of such visual scenes is a controversial issue. In the past, eidetikers were believed to have extremely accurate recall for visual displays, but modern research findings might reveal a different story. Some research demonstrates that eidetic children have greater recall accuracy for visual details compared to non-eidetic children. Other researchers have failed to find any advantage between the two groups. It is also hypothesized that eidetic imagery is not exactly related to memory and improves recall for visual details. If this is true, photographic memory is not particularly useful in the courtroom, which could explain the general failure to detect its existence in adults. Eidetikers cannot produce images of each and every sensory experience on demand. Alternatively, images are created only if the stimulus contains interesting material and a coherent structure. This characteristic critically reduces possible application to criminal justice. Even though there are various thoughts and ideas regarding photographic memory, some people do have exceptional memories, which will help improve the accuracy of eyewitness identification.
The frequency of eidetic imagery
Eidetic Imagery
Eidetic Imagery is a psychotherapy model based on the pioneering work of Akhter Ahsen, Ph.D.- History and Theory :Eidetic Imagery is a fast moving method that identifies areas of need quickly and generates change by using revolutionary tools...
is low in adults and shows greatest frequency in early child development. However it is almost non-existent past the age of 7. When procedures are used to classify eidetic memory separate from the characteristic of afterimage and memory image, a small number of children are classified as true eidetikers.