Factors Affecting the Accuracy of Eyewitness Testimony: Leading Questions & Post-event Discussion (AQA A Level Psychology): Revision Note

Leading questions are those that suggest a certain answer in the way that they are worded

When dealing with eyewitness testimony (EWT), it is vital not to use leading questions, as this could affect the memory of the eyewitness and the accuracy of their testimony, for example:

• 'Did you see the knife?'  (leading) as opposed to 'Did you see a knife?' (not leading)

• Leading questions can, in some circumstances, prompt the eyewitness to recall events incorrectly, for example:

  • 'Did you see the blue panel on the car?' as opposed to 'Did the car have a coloured panel?'

• Leading questions may result in response bias 

  • The eyewitness does not answer the question accurately; they answer in the way that they think they should answer

• 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 of their witnessing the event, e.g., broken glass at the scene of a car crash

Loftus & Palmer (1974) investigated the effect of leading questions on eyewitness recall

Procedure:

• Forty-five student participants (split into five groups) were shown films of car traffic accidents

• After the films, each group was given a questionnaire to complete, which included a critical question in which the verb used to describe the car accident was changed:

  • 'How fast was the car travelling when it _____ the other car?

  • The verbs were: hit, contacted, smashed, collided, bumped

  • Each group had a different verb as part of their questionnaire

  • Each verb constituted one condition of the independent variable

Findings:

• The dependent variable was measured as estimated speed in miles per hour:

  • The lowest estimated speed was for 'bumped' = 38.1 mph

  • The highest estimated speed was for 'smashed' = 40.8 mph

• The researchers concluded that information after the event in the form of a leading question can result in unreliable EWT

There is real-world application with studies into the effect of leading questions, as the findings can be applied to legal fields and the criminal justice system

• This means that there is importance to the accuracy of EWT to ensure that innocent people are not convicted of crimes due to poor recall of events from a witness

Research on leading questions has led to the development of techniques designed to improve witnesses' memory retrieval, such as the cognitive interview (CI) developed by Geiselman et al. (1985)

• The CI is now standard in many police forces, showing that research in leading questions has high ecological validity and social usefulness as it has lead to important changes in the criminal justice system

Lab studies (such as Loftus & Palmer 1974) lack ecological validity because they do not represent real-life situations:

• Eyewitnesses to car accidents are likely to experience high levels of stress which does not happen with lab-based research

• Participants in lab studies may not take the experiment seriously or give the same motivation if they were witnessing a real-life situation

• Answers given by participants may be prone to demand characteristics

• The above observations suggest that the research into leading questions may not have relevance to real-life EWT

EWT research does not account fully for individual differences

• Some people are aware of and can avoid being affected by leading questions

• Some people may feel over-excited, nervous, fearful having witnessed a crime in which case it would be their emotional state rather than the use of leading questions that impaired their memory

Post-event discussion (PED) is another factor affecting the accuracy of EWT

This involves eyewitnesses discussing the events and their experiences after it has occurred

PED can occur in multiple forms, such as:

• discussion with other eyewitnesses

• questioning by legal/crime teams and interviewers

Research by Gabbert et al. (2003) investigated the effect of PED

Procedure:

• Pairs of participants (students and older adults) each watched a different film clip of the same crime so each had a unique view of the event

• Pairs were able to discuss what they had witnessed before carrying out a recall test of the event seen in the video

Findings:

• A large proportion (71%) of eyewitnesses who had discussed the crime made mistakes when recalling the events

• In pairs where no discussion had taken place, 0% of mistakes in recall were made

• This suggests that PED can lead to inaccurate eyewitness testimony

An explanation for the effect PED can have on an eyewitness is memory contamination:

• Eyewitness testimonies can become altered and distorted because of discussions with other eyewitness

• Information from all eyewitnesses is thought to combine, forming incorrect memories

  • This 'pooling' of ideas and opinions could lead to groupthink

Two different populations were investigated as part of the study by Gabbert et al.: students and older adults, which gives the study high population validity

• This suggests that PED affects people in all populations in a similar way

The research performed by Gabbert et al. was a lab study

• Lab studies are easy to replicate; this means there is high reliability to the findings of the investigation

There is low ecological validity because the participants, as part of Gabbert et al.'s study, knew they were taking part in a study

• Participants were likely to have paid close attention to the details of the video clip

• This means that the results do not reflect a real-life crime had it been witnessed

Gabbert et al. could not explain why the effects of PED occurred so the memory distortion could be due to:

• pressure to conform to other eyewitnesses

• poor memory, where people build new information into their memory of the event and are unable to distinguish between what they have seen and what they have heard