Eyewitness testimony
Eyewitness testimony is the account a bystander or victim gives in the courtroom, describing what that person observed that occurred during the specific incident under investigation. Ideally this recollection of events is detailed; however, this is not always the case. This recollection is used as evidence to show what happened from a witness' point of view. Memory recall has been considered a credible source in the past but has recently come under attack as forensics can now support psychologists in their claim that memories and individual perceptions can be unreliable, manipulated, and biased. As a result of this, many countries, and states within the United States, are now attempting to make changes in how eyewitness testimony is presented in court. Eyewitness testimony is a specialized focus within cognitive psychology.
Reliability
Psychologists have probed the reliability of eyewitness testimony since the beginning of the 20th century. One prominent pioneer was Hugo Münsterberg, whose controversial book On the Witness Stand demonstrated the fallibility of eyewitness accounts, but met with fierce criticism, particularly in legal circles. His ideas did, however, gain popularity with the public. Decades later, DNA testing would clear individuals convicted on the basis of errant eyewitness testimony. Studies by Scheck, Neufel, and Dwyer showed that many DNA-based exonerations involved eyewitness evidence.In the 1970s and '80s, Bob Buckhout showed, inter alia, that eyewitness conditions can, within ethical and other constraints, be simulated on university campuses, and that large numbers of people can be mistaken.
In his study, "Nearly 2,000 witnesses can be wrong", Buckhout performed an experiment with 2,145 at-home viewers of a popular news broadcast. The television network played a 13-second clip of a mock robbery, produced by Buckhout. In the video, viewers watched a man in a hat run up behind a woman, knock her over, and take her purse. The perpetrator's face was only visible for about 3.5 seconds. The clip was followed by the announcer asking participants at home for cooperation in identifying the man who stole the purse. There was a lineup of six male suspects, each having a number associated with him. The people at home could call a number on their screen to report which suspect they believed was the perpetrator. The perpetrator was suspect number 2. Callers also had the option of reporting that they did not believe the perpetrator was in the lineup. Approximately equal contingents of participants chose suspects 1, 2, or 5, while the largest group of participants, about 25 percent, said they believed the perpetrator was not in the lineup. Even police precincts called in and reported the wrong man as the one they believed committed the crime. A key purpose of this experiment was aimed toward proving the need for better systems of getting suspect descriptions from eyewitnesses.
The question at hand is: What is there about an event that makes it so easy for eyewitness testimonies to be misremembered? As it pertains to witnessing crime in real time, “uniqueness is overshadowed by the conditions for observations”. The surprise or shock over the fact that a crime is happening puts the visceral experience of the event large, front and center of attention for a witness or a victim. However, this also has the effect of making it difficult for them to pay close attention to every material detail of the event; that is, their ability to remember any particular thing that potentially could be remembered will likely be diminished, because the ability to observe carefully, completely, accurately and objectively is handicapped by a number of factors constituent to the incident:
- The time of day – was there enough light to really see the event?
- Crowd density at the scene;
- Was there anything uncommon or marked about the perpetrator's features?
A person's memory can be influenced by things seen or heard after a crime has occurred. This distortion is known as the post-event misinformation effect After a crime occurs, and an eyewitness comes forward, law enforcement tries to gather as much information as they can, in order to avoid any influence that may come from the environment, such as the media. Many times, when the crime is surrounded by much publicity, an eyewitness may experience source misattribution. Source misattribution occurs when a witness is mistaken about where or when they have the memory from. If a witness identification of the source of their retrieved memory turns out to be mistaken, then the witness will be considered unreliable.
While some witnesses see the entirety of a crime happen in front of them, others only witness part of a crime. These latter witnesses are more likely to experience confirmation bias. Witness expectations are to blame for the distortion that may come from confirmation bias. For example, Lindholm and Christianson found that witnesses of a mock crime, who did not witness the whole crime, nevertheless testified to what they expected would have happened. These expectations are normally similar across individuals, due to the details of the environment.
The responsibility to evaluate the credibility of eyewitness testimony falls on each individual juror, when such evidence is offered as testimony in a trial in the United States. Research has shown that mock juries are often unable to distinguish between a false and accurate eyewitness testimony. "Jurors" often appear to correlate the confidence level of the witness with the accuracy of their testimony. An overview of this research by Laub and Bornstein shows this to be an inaccurate gauge of accuracy.
Working memory
Three ways affect influences memory: 1. emotional events can create positive and negative influences on the memory of an individual. 2. memory itself can manipulate and/or create emotions of an individual. 3. Working memory establish feelings as mental representations.Feelings influence thoughts, decisions, and actions which means impairment can also be caused because of a person's emotional state. Emotional distracters can disrupt the working memory causing decreased activity in the processing portions of the brain.
In terms of neuroscience studies, the more negative presence of images within the brain, the more delay there is in terms of remembering and recalling events.
Depending on the ages of individuals this also has an impact on affective working memory processes. There are different decision making strategies an processes between children, adolescence, teens and adults, therefore, this can establish different perceptions of emotions, processing events, and recalling events with emotions that may be more negative to deal with in terms of age, or may be easier to recall. Depending on the events, the age, and the cognitive processing in terms of emotions, there can be more memory improvement or lack of knowledge and insight of even accounts.
Cognitive activity and representations in terms of the way a person makes decisions, processes events and emotions, and recalling decisions in terms of Affective Working Memory, this ties into the cognitive understanding and analysis testimonies and the psychological components on an individual depending on various circumstances.
Research on eyewitness testimony looks at systematic variables or estimator variables. Estimator variables are characteristics of the witness, event, testimony, or testimony evaluators. Systematic variables are variables that are, or have the possibility of, being controlled by the criminal justice system. Both sets of variables can be manipulated and studied during research, but only system variables can be controlled in actual procedure.
Estimator variables
Memory conformity
When a crime occurs with multiple witnesses, the first reaction of a witness is usually to ask another to confirm what they just saw. If multiple witnesses are required to stay at the scene of the crime, they are more likely to confer with each other about their own perspectives. This can lead to memory conformity. Memory conformity is when one reports another person's experience as their own. In some cases this can be a positive phenomenon, if enough people saw the right thing and were able to report it accurately. However, most memory conformity comes from wanting one's personal experience to match that of others. Individuals who identify a suspect with blonde hair will most likely change their answers upon learning two other people reported the suspect had brown hair; “People may agree with another person because of normative pressures to conform even when they believe the response is in error”Short-term memory of identifier
In the event of witnessing a crime happening quickly, one can be susceptible to being in a state of shock. Once the initial surprise wears off, an individual can be left wondering what exactly happened. The problem with witnesses trying to recall such specific information is that short-term memory only keeps items in the brain for about 10 to 15 seconds. This means that if someone is not repeating everything they just witnessed over and over again to convert it over into their working or long-term memory, there is a good chance they can only remember the basic facts of the situation. Perceived or elapsed time can be altered during sudden or surprising events and influence eyewitness testimony.Age of witness
Among children, suggestibility can be very high. Suggestibility is the term used when a witness accepts information after the actual event and incorporates it into the memory of the event itself. Children's developmental level causes them to be more easily influenced by leading questions, misinformation, and other post-event details. Compared to older children, preschool-age children are more likely to fall victim to suggestions without the ability to focus solely on the facts of what happened.Research on childhood memory shows that false memories can appear very early in the remembering process. They do not only happen when someone forgets or is influenced by leading questions later on. Age makes a difference in how children handle this. Older children are often better at realizing when something they remember does not match what really took place. The process is called recollection rejection. It helps them tell apart real experiences from imagined ones. However, the younger children are more inclined to believe in the imagined details if it matches what they saw in terms of the general feeling it evokes.
False impressions can start forming as children first take in and store information. When they focus on the main idea, or gist, they sometimes fill in missing parts in ways that seem to make sense. This can lead them to remember things that never actually happened. A review of developmental memory research found that this gist-based process appears in all age groups and can cause false recall even without misleading questions. These findings suggest that memory errors in children can arise naturally from how they process and understand events, not only from outside suggestion or later forgetting.
In addition, a recent meta-analysis found that older adults tend to be more susceptible to memory distortion brought about by misleading post-event information, compared to young adults.