Discuss Factors Affecting the Reliability of Eye-Witness Testimonies

Discuss Factors affecting the reliability of EWTs.

Misleading information is incorrect information given to the eyewitness usually after the event. It can take many forms, including leading questions and post-event discussion. A leading question is a question which, because of the way it is phrased, suggests a certain answer.

Loftus & Palmer (1974) arranged for students to watch film clips of car accidents and later gave them questions about the accident. In the critical (leading) question participants were asked to describe how fast the cars were travelling- “about how fast were the cars going when they hit each other”. 5 groups of participants were given a different verb in the critical question- hit, contacted, bumped, collided, smashed. It was found that when the mean estimated speed was calculated for each group, contacted – 31.8mph and smashed – 40.5mph. This shows the leading question biased the eye witness recall.

It was a lab experiment therefore has low ecological validity as it involved an artificial task so may tell us very little about how leading questions affect cases of real accidents or crimes. The eye witnesses were aware they had to pay attention, would not be in real life. Also, a film clip rather than real life experiences would lack stress levels provided by a real life experience. However, the research had hugely important practical uses in the real world as questions are now asked differently.

The results were explained by the response-bias explanation which suggests that the wording of the question has no real effect on the participant’s memories, it just influences how they decide to answer. Leading questions can initiate demand characteristics (Zaragosa & McCloskey 1989). For example, asking ‘did you see the blue car?’ even if there was no blue car can cause the participant to answer ‘yes’ because it seems helpful to the researcher.

A further factor is that of post event discussion. Gabbert et al (2003) studied pairs of participants who watched a video of the same crime but filmed from different positions. There were 60 university students and 60 older adults in the sample. Each participant could see elements in the video that others couldn’t. Both participants would discuss what they had seen before individually completing a recall test. The video showed a girl stealing money from a wallet. The researchers found that 71% of participants mistakenly recalled parts of the event that they didn’t see in the video with 60% saying the girl was guilty without having seen her commit the crime because they had heard the discussion. The control group had an error percentage of 0%. They completed a questionnaire which tested their memory. Gabbert concluded that witnesses went along with each other to gain social approval or because they assumed the others would be right and that they were wrong. They called this memory conformity.