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For example, they may be required to describe a trial of a robbery or a road accident someone has seen. This includes the identification of perpetrators, details of the crime scene, etc.
Eyewitness testimony is an important area of research in cognitive psychology and human memory.
Anxiety / Stress
This means that for tasks of moderate complexity (such as EWT), performance increases with stress up to an optimal point where it starts to decline.
Clifford and Scott (1978) found that people who saw a film of a violent attack remembered fewer of the 40 items of information about the event than a control group who saw a less stressful version. As witnessing a real crime is probably more stressful than taking part in an experiment, memory accuracy may well be even more affected in real life.
They showed that witnesses of a real-life incident (a gun shooting outside a gun shop in Canada) had remarkable accurate memories of a stressful event involving weapons. A thief stole guns and money, but was shot six times and died.
The Yuille and Cutshall study illustrates two important points:
There are cases of real-life recall where memory for an anxious / stressful event is accurate, even some months later.
Misleading questions need not have the same effect as has been found in laboratory studies (e.g. Loftus & Palmer).
Reconstructive Memory
Bartlett’s theory of reconstructive memory is crucial to an understanding of the reliability of eyewitness testimony as he suggested that recall is subject to personal interpretation dependent on our learned or cultural norms and values, and the way we make sense of our world.
Many people believe that memory works something like a videotape. Storing information is like recording and remembering is like playing back what was recorded. With information being retrieved in much the same form as it was encoded.
However, memory does not work in this way. It is a feature of human memory that we do not store information exactly as it is presented to us. Rather, people extract from information the gist, or underlying meaning.
Schemas are, therefore capable of distorting unfamiliar or unconsciously ‘unacceptable’ information in order to ‘fit in’ with our existing knowledge or schemas. This can, therefore, result in unreliable eyewitness testimony.
Bartlett tested this theory using a variety of stories to illustrate that memory is an active process and subject to individual interpretation or construction.
In his famous study “War of the Ghosts”, Bartlett (1932) showed that memory is not just a factual recording of what has occurred, but that we make “effort after meaning”.
By this, Bartlett meant that we try to fit what we remember with what we really know and understand about the world. As a result, we quite often change our memories so they become more sensible to us.
His participants heard a story and had to tell the story to another person and so on, like a game of “Chinese Whispers”.
The story was a North American folk tale called “The War of the Ghosts”. When asked to recount the detail of the story, each person seemed to recall it in their own individual way.
With repeating telling, the passages became shorter, puzzling ideas were rationalized or omitted altogether and details changed to become more familiar or conventional.
For example, the information about the ghosts was omitted as it was difficult to explain, whilst participants frequently recalled the idea of “not going because he hadn’t told his parents where he was going” because that situation was more familiar to them.
It seems, therefore, that each of us ‘reconstructs’ our memories to conform to our personal beliefs about the world.
This clearly indicates that our memories are anything but reliable, ‘photographic’ records of events. They are individual recollections which have been shaped & constructed according to our stereotypes, beliefs, expectations etc.
When asked to recall details of the picture opposite, participants tended to report that it was the black man who was holding the razor.
Clearly this is not correct and shows that memory is an active process and can be changed to “fit in” with what we expect to happen based on your knowledge and understanding of society (e.g. our schemas).
Weapon Focus
This refers to an eyewitness’s concentration on a weapon to the exclusion of other details of a crime. In a crime where a weapon is involved, it is not unusual for a witness to be able to describe the weapon in much more detail than the person holding it.
Loftus et al. (1987) showed participants a series of slides of a customer in a restaurant. In one version, the customer was holding a gun, in the other the same customer held a checkbook.
Participants who saw the gun version tended to focus on the gun. As a result, they were less likely to identify the customer in an identity parade those who had seen the checkbook version
References
Allport, G. W., & Postman, L. J. (1947).The psychology of rumor. NewYork: Holt, Rinehart & Winston.
Bartlett, F.C. (1932).Remembering: A Study in Experimental and Social Psychology. Cambridge: Cambridge University Press.
Clifford, B.R. and Scott, J. (1978). Individual and situational factors in eyewitness memory.Journal of Applied Psychology, 63, 352-359.
Deffenbacher, K. A. (1983). The influence of arousal on reliability of testimony. In S. M. A. Lloyd-Bostock & B. R. Clifford (Eds.).Evaluating witness evidence. Chichester: Wiley. (pp. 235-251).
Loftus, E.F., Loftus, G.R., & Messo, J. (1987). Some facts about weapon focus.Law and Human Behavior, 11, 55-62.
Yerkes R.M., Dodson JD (1908). The relation of strength of stimulus to rapidity of habit-formation.Journal of Comparative Neurology and Psychology, 18: 459–482.
Yuille, J.C., & Cutshall, J.L. (1986). A case study of eyewitness memory of a crime.Journal of Applied Psychology, 71, 291-301.
Olivia Guy-Evans, MSc
BSc (Hons) Psychology, MSc Psychology of Education
Olivia Guy-Evans is a writer and associate editor for Simply Psychology. She has previously worked in healthcare and educational sectors.
Saul McLeod, PhD
BSc (Hons) Psychology, MRes, PhD, University of Manchester
Saul McLeod, PhD., is a qualified psychology teacher with over 18 years of experience in further and higher education. He has been published in peer-reviewed journals, including the Journal of Clinical Psychology.
