Year 10 Psychology — Eyewitness Testimony
Task 1 — Specific court case
There was a court case including a man called Troy Davis, who supposedly shot a police officer intervening in a fight at a ‘Burger King’ car park. According to the court, the “case centred on eyewitness testimony”.[1] The eyewitness testimony consisted of a lineup, a test long known to result in serious mistakes. The officer in charge of conducting such a test, however, knew who the suspect was and gave inadvertent cues. The officers openly suggested to the eyewitnesses whom to pick out, as well as showing single photos of the suspect they had in mind. Even making suggestive comments is considered police misconduct. The police did show a five-photo array with Davis’ picture in it, but they waited five to ten days before using it to test the eyewitnesses. In the meantime, the officers planted wanted photos with Troy Davis’ image—the same photo in the photo array—around the neighbourhood. Witnesses also described feeling pressure put on them by the police officers to choose the right suspect.[1]
In this case of misidentification, many components of memory have affected the eyewitness accounts Troy Davis’ court case.
Long-term memory is one of the predominant components that could have affected eyewitness’ judgment. This form of memory, also known as LTM, is the stage of memory where information can remain indefinitely. However, over time, this information can begin a process known as the decay theory. This means that knowledge is less available for retrieval as time passes and the strength of the memory wears away. In the court case, the police waited five to ten days before providing a photo array of suspects to the eyewitnesses.[1] During this time period, the amount of decay that could have happened surrounding the incident in the witness’ brains may have concealed certain details.
The same process of decay had to have occurred to the eyewitness’ sensory memories. These memories are responsible for immediate visual and echoic processing lasting around three to four seconds. After this amount of time, most of the information about the incident had been discarded by the eyewitness, only leaving the vague story later available for recall.
Stress is also a component that could have affected eyewitness’ decisions, especially in this case. The witnesses involved reported to have been put through a fair amount of pressure to choose the right suspect and please the officers. One of the witnesses testified that they were told that “if I don’t cooperate with them, that I’m gonna be in prison for ten to twelve years.”[1] This would put stress on the witness, and therefore make it easier for them to identify the wrong person.
Another component that may have led to the misidentification was selective attention, or more specifically in this case, weapon focus. Selective attention describes the limited ability that humans have to process multiple details when several events occur simultaneously. One eyewitness said at the trial that “I was nervous, I was watching the gun.”[1] In situations where there are dangerous weapons involved, eyewitnesses are more likely to divert their attention to the weapon rather than the face of the person manning the weapon.
During the trials, lineup, and photo array, the eyewitnesses must have used controlled processing to identify whom they thought was the suspect. Controlled processing requires us to pay attention and make a deliberate effort, whilst automatic processing does not require attention or much effort. When recognising people we generally know well, we use automatic processing to identify them. However, in the court case, the eyewitnesses must have used controlled processing in an attempt to identify the suspect. This conscious thought in the decision-making process to identify who the the suspect was left room for error.
The recognition of Troy Davis caused by the posters the officers put up around town may have also caused the witnesses to misidentify him as the suspect.[1] Due to the fact that eyewitness memory decays rapidly and that the photograph used was the same in the photo array shown later, the recency effect may have played a role in the case. The eyewitnesses could have chosen Davis because he was the last face from the crime scene that they saw. This ability to easily recall information that was last observed is known as the recency effect.
Task 2 — Unethical to rely solely on eyewitness testimony
Memory is malleable, which means that it is easily changed and can be altered to fit expectations. In any court of law, eyewitness testimony is not a completely reliable source. This is not just because of a possible lie, but because the memory of the eyewitnesses when recalled would be significantly different than when it was first encoded into the brain. Memories can convince humans that they saw something that wasn’t actually present.[2]
Retroactive interference occurs when new information is processed that obstructs the accurate retrieval of previously learned material. This can allow eyewitness testimony to be unethical to rely upon in a situation such as that of a witness reporting a crime. Police officers that have reason to believe that a certain suspect is guilty, the biased questions that they ask can influence the eyewitness’ episodic memory of the event.[3] The presence of a co-witness retelling the event can also contaminate the eyewitness’ accounts, perhaps even agreeing on an incorrect recollection.
The leading questions asked by police investigators encourages witnesses to answer in the way the officers want them to, for example choosing a suspect that the officers are skeptical about.[3]
Task 3 — Strategies for making eyewitness identification more reliable
Strategies for making the risk-filled process of eyewitness identification more reliable. In police lineups and photo arrays, the basic method is to place a suspect or suspects among “fillers” and asking the eyewitness if they can identify if the perpetrator is in the line or array.[4] The problem with this is that the police investigators are biased in placing the real suspects in certain positions within the lineup. Computer-assisted lineups add the benefits of random selection in the placement of the photos within the array.[5] Doing this and telling the eyewitness that it is computer-generated creates a less-biased presentation and lowers the risk of misidentification by the eyewitness.
Another strategy to make identification more reliable is to provide context-dependent cues to the eyewitness after interviews.[3] These cues that could be provided could be as simple as returning to the scene of the crime (however this may perhaps raise ethical issues). This is because some knowledge of the event could be context-dependent, which means that the recall of specific information is significantly improved when the context present at both encoding and retrieval are the same. However, retroactive interference may occur when context is provided.
State-dependent memory is similar to context-dependent memory, although state-dependent refers to the state of consciousness (eg. emotions) being the same as they were when the memory was encoded.[3] Somehow making the eyewitness experience the emotion that they felt at the time of the incident may allow information to be more accurately recalled, thus leading to the correct identification of the criminal.