Describe and Evaluate Studies of Eyewitness Testimony (12)

One study of eyewitness testimony (EWT) was by Loftus and Palmer. Their aim was to see whether asking leading questions had any effect on recall.

The method used was a laboratory experiment and had two parts to it. The first was showing participants (Ppts) 7 films of car accidents. Participants were then asked questions, including “How fast were the cars travelling when they **** each other?” The asterisks were then replaced with a different verb, including “smashed” and “hit.” The second part of the experiment involved using the same participants one week later and asking them the following question, “Was there any broken glass in the film?” There was, however, no broken glass.

The independent variable was the changing of the verb in the first question and the dependant variable the estimated speed of contact.

The results of the first part of the experiment showed that there was a 10 mph speed difference between the verbs “smashed” compared to “contacted.” The results from the second part show that using the verb “smashed” lead to 52% believing there was broken glass, compared to only 14% believing there was broken glass when the verb “hit” was used.

Loftus and Palmer then concluded that wording, and therefore leading questions, have an effect on recall of an event.

The study by Loftus and Palmer can be generalised to the whole of the population because the study concerns memory and everyone has one. It can be assumed they work in the same way and will therefore be affected in the same way by leading questions.

It can be argued that the study has high reliability because the questions and videos were standardised. This is good because it makes the study easily repeatable and the results can be confirmed. This in turn is good because it makes the study more scientific.

However, the study lacks validity because real life is not as controlled as in the lab. This is due to the prior warning, video clips and lack of normal distractions. This is bad because it does not represent real life, meaning the results should not be generalised to real life and EWs as part of police investigations.

The study has social implications because it, in part, led to courts not being allowed to convict on EWT alone. This is good because it meant that innocent people would not be convicted due to the likely inaccuracies of EWT.

The study also has moral implications for the Ppts involved. These are very minor, because they would not have been stressed. Ppts were deceived, but this was justified because without it Ppts would have shown demand characteristics, leading to unrepresentative and inaccurate results.

Another study is by Loftus and Messo where the aim was to assess the support for the weapons effect.

36 American students took part in the laboratory experiment. Ppts were shown two sets of slides and their eye movement was recorded throughout. The control was a queue in a restaurant were a cheque was used to pay by Person B. The experimental was the same queue but a gun was drawn by Person B and cash handed over. After a period of filler slides, Ppts were asked questions –relating to Person B or miscellaneous questions. Finally, Ppts were asked to try to identify Person B from a line-up of 12 photographs.

Results