2.4 Eye Witness Testimony: AQA Psychology A level Revision

Eye witness testimony

Eyewitness testimony (EWT) has been given huge importance in criminal trials and is often the key piece of evidence used to convict someone. Some psychological research has revealed that EWT can be unreliable under certain conditions. Leading questions may lead to unreliable EWT being given and, ultimately, an innocent person being convicted.

What is leading question?

Leading questions may result in response bias, i.e., the eyewitnesses do not answer questions accurately: they answer how they think they should answer(this may occur without someone realising it is happening).

The substitution explanation proposes that a leading question changes a person's memory of an event by adding detail that was not present at the time e.g.broken glass at the scene of a car crash (as in Loftus and Palmer 1974)

Research into leading questions

Loftus and Palmer (1974)- the strength of the verb used in the critical question (e.g.'smashed' as opposed to 'contacted') may have led participants to estimate higher speed estimates accordingly, i.e. 'smashed' elicited higher speed estimates probably because it 'sounds faster'.

Yuille and Cutshall (1986)- participants who had been real-life eyewitnesses of the shooting were not misled by false information and leading questions

How does anxiety affect an eyewitness?

Anxiety can have either a positive effect or a negative effect on an eyewitness. Being in a heightened state of physiological arousal (fight or flight) can enhance EWT.

Tunnel theory proposes that a weapon's presence can negatively affect EWT (weapon focus effect). The Yerkes-Dodson law applies to EWT and anxiety, as too much arousal induced by anxiety can impair cognitive functions such as memory.

Research support for EWT and anxiety

Yuille and Cutshall (1986) - participants who had been real-life eyewitnesses of a shooting were not misled by false information and leading questions (positive affect on memory).

Loftus et al. (1987)- participants who saw a picture of a customer in a restaurant holding a gun were less likely to identify that same customer in an identity parade than participants who had seen him with a check-book (negative effect on memory).

What is the cognit ive interview?

The cognitive interview (CI) is a method of interviewing eyewitnesses about what they can recall from a crime scene or event. It was developed to improve EWT in order to enhance recall and thus lead to the more accurate conviction of the perpetrator.

Cognitive interview techniques

- Recall everything (witnesses are asked to recall as much detail as they can, however trivial it might seem) - Recall the events in reverse order (witnesses are asked to recall the event using different chronologies, i.e. start at the end, start from the middle, etc.)

- Reinstate the context (the witness has to think about what was happening at the time of the event: Was it raining?)

- Change the perspective (the witness is asked to view the event from someone else's viewpoint, e.g. the perpetrator or another witness. It should ensure that schemas are not activated so that preconceived ideas do not influence the memory, e.g. I was in a restaurant, and this is what usually happens in a restaurant).

Research support for the cognit ive interview

Fisher (1999)- the CI was found to produce 46% more detail and was 90% more accurate than standard police interviews.

Milne and Bull (2002)- found that 'report everything' and 'reinstate the context' are better at producing recall than the other two elements of the CI.