Eyewitness Testimony An Enduring Topic Of Psychological Enquiry

Eyewitness Testimony An Enduring Topic Of Psychological Enquiry



The study of​ eyewitness testimony can be traced back over 100 years. This article outlines how it​ all began and examines the most commonly researched areas of​ investigation.

In 1896 Albert Von Schrenk-Notzing testified at​ the trial of​ a​ man accused of​ murdering three women. Drawing on research into memory and suggestibility he argued that pre-trial publicity meant that witnesses could not distinguish between what they actually saw and what had been reported in​ the press.

The formal study of​ eyewitness testimony is​ usually examined within a​ framework of​ cognitive processing, which put simply refers to​ the different ways in​ which we make sense of​ the world around us.

We do this by employing the mental skills at​ our disposal such as​ thinking, perception, memory, awareness, reasoning and judgment. Although cognitive processes can only be inferred and cannot be seen directly, they all have very important practical implications within a​ legal context.

Given that the way we think, perceive, reason and judge can be less than perfect it’s easy to​ understand why the factors influencing these processes are studied by psychologists'; not least because of​ the grave implications that this imperfection can have within the criminal justice system. as​ Huff and Rattner note:

the single most important factor contributing to​ wrongful conviction is​ eyewitness misidentification.

Stages of​ eyewitness memory:

Stage 1: Witnessing the incident.

When witnessing an​ incident, information about the event is​ entered into memory, however, research has shown that the accuracy of​ this initial information acquisition can be influenced by a​ number of​ factors.

Take the duration of​ the event being witnessed for instance. in​ a​ very simple experiment conducted by Clifford and Richards(1977), participants are instructed to​ approach a​ number of​ police officers and engage in​ conversation for either 15 or​ 30 seconds.

Thirty seconds after the conversation ends, the experimenter asks the police officer to​ recall details of​ the person they had just been speaking to​ using a​ 10-item checklist. The checklist contains items relating to​ the persons appearance such as​ hair colour, facial hair etc. The results of​ the study showed that in​ the longer 30 second condition, police were significantly more accurate in​ their recall.

Stage 2: Waiting period before giving evidence.

This stage is​ concerned with the period of​ retention between perception i.e., seeing an​ incident and the subsequent recollection of​ that incident. Unsurprisingly, research has consistently found that the longer the gap between witnessing an​ incident and recalling the incident, the less accurate the recollection of​ that incident becomes.

There have been numerous experiments, usually related to​ a​ staged event, that support this contention. Malpass and Devine (1981), for instance, compared the accuracy of​ witness identifications after 3 days (short retention period) and 5 months (long retention period). The study found no false identifications after 3 days but after 5 months, 35% of​ identifications were false.

Stage 3: Giving evidence.

The final stage in​ the eyewitness memory process relates to​ the ability of​ the witness to​ access and retrieve information from memory. in​ a​ legal context, the retrieval of​ information is​ usually elicited through a​ process of​ questioning and it​ is​ for this reason that a​ great deal of​ research has investigated the impact of​ types of​ questioning on eyewitness memory.

The most substantial body of​ research has concerned leading questions, which has consistently shown that even very subtle changes in​ the wording of​ a​ question can influence subsequent testimony.

One of​ the most notable researchers in​ this field is​ Elizabeth Loftus who has been investigating eyewitness testimony for over thirty years. in​ one of​ her classic studies, participants witnessed a​ film of​ a​ car accident and were asked to​ estimate the speed of​ the cars involved. One group of​ witnesses were asked to​ estimate the speed of​ the cars when they contacted each other. a​ second group of​ witnesses were asked to​ estimate the speed of​ the cars when they smashed each other.

On average the first 'contacted' group gave an​ estimate of​ 31.8 miles per hour. Whereas, the average speed in​ the 'second' smashed group was 40.8 miles per hour.

Experimental validity:

In any discussion of​ eyewitness memory, you'll see the terms, 'experiment', 'participants' and 'staged event' frequently used. This is​ because the majority of​ research into eyewitness memory has been conducted within psychology laboratories.

This raises the very important issue of​ whether it​ is​ possible to​ generalise the findings obtained under these artificial conditions to​ real life cases.

The simple, if​ unsatisfactory answer is​ that it​ is​ very difficult to​ say. Take for instance the work of​ Yuille and Cutshall, these researchers conducted a​ case study with witnesses to​ a​ real shooting incident, interviewing them just after the event and again 5 months later. They concluded that the performance and accuracy of​ the witnesses differed in​ several respects to​ what would be expected according to​ the experimental literature.

However, the strength of​ laboratory based research is​ that the experimenter is​ able to​ exercise a​ great deal of​ control over what happens. in​ the case study reported by Yuille and Cutshall, it​ was impossible to​ know the extent to​ which the witnesses had conferred and how much media coverage of​ the incident they had seen, and how much influence this had on their testimony.

If you'd like to​ find out more about eyewitness memory, you can do so by visiting www.all-about-forensic-psychology.com




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