Lesson 10 Eyewitness Testimony

Question 1

Eyewitness Testimony

Answer 1

Eyewitness testimony (EWT) is the evidence supplied to a court by people who have seen a crime, based on their memory of the incident. This evidence can include an identification of the perpetrator or details of the crime (sequence of events, the time of day etc.). Juries are often heavily influenced by eyewitnesses.

Question 2

Leading Questions

Answer 2

Leading questions are questions that are phrased in such a way as to encouragea witness to give a certain answer. The response-bias explanation argues that leading questions do not affect memory, merely the answer a person chooses to give. However, the substitution-bias explanation proposes that leading questions distort memories because they contain misleading information.

Question 3

Loftus and Palmer (1974) Procedure

Answer 3

• Loftus and Palmer (1974) showed 45 American students a film of a car crash and then asked them to estimate the speed that the cars were travelling when they crashed. However different verbs were used in the question depending on the condition. The verbs were contacted, hit, bumped, collided, or smashed.

Question 4

Loftus and Palmer (1974) findings

Answer 4

Participants in the ‘contacted’ condition estimated the speed as 31mph but in the ‘smashed’ condition participants estimated the speed as 41mph. A week later participants were asked if they saw any broken glass, even though there was no broken glass shown in the film. 32% of the participants in the smashed’ condition reported seeing broken glass compared to only 12% in the control condition. This shows that leading questions have a significant impact on what people recall and can change a person’s entire memory of an event.

Question 5

Advantages of Leading Questions

Answer 5

+ This study is a laboratory experiment and was therefore highly controlled. This reduces the chance of extraneous variables, increasing the validity of the results. Furthermore, it is easy for psychologists to replicate their research study to see if the same results are found, meaning the study is reliable.

Question 6

Disadvantages of Leading Questions

Answer 6

• This study has questionable ecological validity. The participants watched a video of a car crash. People who witness a real car accident, who have a stronger emotionally connection to the event, may not be as susceptible to leading questions.
• This study also lacks population validity. The study consisted of 45 American students. Students are less experienced drivers may be less competent at estimating speeds. Consequently, we are unable to generalise the results of this study to other populations. Older and more experienced drivers may be more accurate in their judgement of speeds and therefore less susceptible to leading questions.

Question 7

Post-Event Discussion

Answer 7

The memory of an event can be contaminated through discussing events with others due to misinformation (memory contamination). Also, a desire for social approval can lead co-witnesses to reach a consensus view of what happened (memory conformity)

Question 8

Gabbert et al. (2003) procedure

Answer 8

• Gabbert et al. (2003) put participants in pairs and got them to watch a different video of the same event so that they each got unique details. In one condition the pairs were encouraged to discuss the event with one another before individually recalling the event. In the other condition they didn’t discuss what they had seen with one another.

Question 9

Gabbert et al. (2003) Findings

Answer 9

71% of witnesses who had discussed the event went on to mistakenly recall details that they could not have seen themselves, but that they had learned of during the discussion with their partner.

Question 10

Advantages of Post Event Discussion

Answer 10

+ This study has population validity. Two different populations, students and older adults, were compared and there were no significant differences between these two groups. This allows us to conclude that post-event discussion affects younger and older adults in a similar way.

Question 11

Disadvantages of Post-Event Discussion

Answer 11

This study lacks ecological validity. The participants knew they were taking part in the experiment and they are therefore more likely to have paid more attention to the details of the video clip. The results don’t reflect real life where witnesses may be exposed to less information