AQA A Level Psychology复习笔记2.4.1 Eye Witness Testimony & Leading Questions

Eye witness testimony and leading questions

•  It is felt that eye witness testimony (EWT) is important in criminal trials, with over 1/3rd of people believing that one single witness is enough to convict someone in a trial. (Simons and Charles 2011)
• Yet this is an over-simplification and psychological research into EWT has shown it is often unreliable.

Misleading information: Leading questions

What is leading question?

• This is a question that suggests the desired answer that the person asking it wants
• It links to misleading information as it can prompt the responder, in this case the witness, to give incorrect information: Misleading information
• Example: Did the robber have a black jumper and blue trousers on when he robbed the petrol station?
• A better question would be ‘What was the robber wearing when he robbed the petrol station?

Research into leading questions

Loftus and Palmer (1974) part 1

• They conducted a laboratory experiment that involved 45 participants (Ps) placed into 5 groups of 9 Ps
• They then watched 7 films about car accidents and at the end of each were asked a series of questions
• One question asked how fast the cars were going when they ______________ into each other
• The 5 groups were then given a different verb: Either collided, bumped, hit, contacted or smashed
• This was an independent design: They only heard one verb
• The average speeds given were then calculated
• It was found that the average speed for ‘smashed’ was the highest (40.8 mph) compared to 31.8mph for ‘contacted’
• This shows the verb in the question prompts misleading information from the participant

Loftus and Palmer (1974) part 2

• They then did a follow-up experiment with 150 students who were shown one film of a car accident
• The 5 verbs were used again (smashed/collided/hit/contacted/hit) in an independent design
• They were once again asked questions but this time an additional question was added: ‘Did you see the broken glass?’
• A week later the students were all re-interviewed and asked what they could recall
• The ‘smashed’ condition reported seeing broken glass twice as many times as the hit condition: 16 reported it
• There was no broken glass
• Loftus argued that the misleading question had actually altered a person’s memory of the event

Evaluation of EWT and misleading information/leading questions

• The studies lacked ecological validity: The participants knew it was only an experiment and their answers had no consequences
• Watching a film of an event is also very different from watching the actual event in real life
• The experiment took over 2 hours to complete so Ps could easily have been bored
• The real speeds of the cars were around 20mph so all the averages were too high anyway and in the experiment, participants were not good at estimating speeds
• Individual differences could be a factor here: Some of the Ps may not have driven so car speeds would be less known about
• Broken glass is part of the schema for a car accident so it may be that the reason for the (false) recall of broken glass in experiment 2
• There are ethical implications of the experiment: It could have been psychologically harmful to witness these crashes
• Loftus, in her Red Purse/Brown purse study (1979) shows that certain information (i.e. memorable or very obvious) is very hard to mislead people wit
• What does happen to the original memory if it has been replaced?
• But it was a well-designed experiment and counter-balancing was used to ensure that order effects were not a problem: The five groups all watched the films in a different order
• There are huge practical applications to the study: Used by police and legal representatives to ensure leading questions are not used so as not to bias a witness