Factors affecting eyewitness testimony

Eyewitness testimony Eye witnesses who have ‘seen with their own eyes’ tend to be believed more by juries than fingerprint experts. As a Psychology student who has studied the topic of memory, you will know that peoples’ memories are NOT perfect.

Aims... To describe the Loftus and Palmer study Be able to apply cognitive psychology to help understand the problems of eyewitness testimony

Task You have just been a witness to a crime, and the police want you to recall as many details as you can remember. Using your knowledge of Psychology, what factors will influence how accurate your memory is? HINT: think about the theories of memory and forgetting we have looked at.

Hints.... multi store model levels of processing reconstructive theory Emotioninterferencedecay

Initial Ideas...

Loftus and Leading Questions How does information presented after an event affect a witness’s memory for that event?

Method Two laboratory experiments Independent measures design IV = Verb used DV = The estimate of speed or whether the P saw glass

Method – Experiment 1 45 student participants were shown short video clips They were split into 5 groups, with 9 participants in each one All of the participants were asked: ‘About how fast were the cars going when they ________ each other’ Each group was given a different verb to fill in the blank. These verbs were ‘smashed, collided, bumped, hit or contacted’. Therefore the independent variable was the verb used. The dependent variable was the estimate of speed given by the participants

Results – Experiment 1 VERB MEAN ESTIMATE OF SPEED (mph) Smashed40.8 Collided39.3 Bumped38.1 Hit34.0 Contacted31.8 How the question was phrased influenced the participants’ speed estimates When the verb ‘smashed’ was used, participants estimated that the cars were travelling much faster than when the verb ‘contacted’ was used. What do these results show?

Method – Experiment student participants were shown a short film that showed a multi- vehicle car accident and then they were asked questions about it. The participants were split into 3 groups (with 50 in each group). One group was asked: ‘How fast were the cars going when they hit each other?’ The second was asked: ‘How fast were the cars going when they smashed into each other?’ The third group was not asked about the speed of the vehicles One week later, all participants returned and were asked: ‘Did you see any broken glass?’ There was no broken glass in the film.

Results – Experiment 2 ResponseSmashedHitControl Yes1676 No Did you see any broken glass? The results show that the verb used in the original question influenced whether the participants thought they had seen broken glass. What do these results show?

Explaining Loftus and Palmer’s results Key Words In pairs, develop some key words that will help you remember the results of the study… You could then use these as cue cards / revision cards!