Elizabeth Loftus and John Palmer 3 Core study Reconstruction of automobile destruction: an example of the interaction between language and memory Elizabeth Loftus and John Palmer

Aim To investigate whether phrasing of a question can influence judgement of speed

Background Marshall (1969) found that people had difficulty estimating the speed of cars even if they knew that they would be asked about it. Daniel (1972) found that memory is effected by verbal labels.

Method: Experiment 1 Laboratory experiment Independent design

Independent variable: Experiment 1 Verb used in question smashed collided bumped hit contacted

Dependent variable: Experiment 1 Estimate of speed

Participants: Experiment 1 45 students groups of various sizes

Procedure: Experiment 1 Seven films of traffic accidents were shown. After each film, participants were given a questionnaire. Firstly, they had to give an account of the accident. Secondly, they had to answer some questions.

Critical question About how fast were the cars going when they hit each other? Other verbs substituted for ‘hit’: smashed collided bumped contacted

Results: Experiment 1 Mean speed estimates smashed 40.8 mph collided 39.3 mph bumped 38.1 mph hit 34.0 mph contacted 31.8 mph

Conclusions The form of the question can significantly affect a eyewitness’s answer to it. This could be because of: Response bias: uncertain participants use the verb to bias their response Change in memory of accident: the verb makes the witness see a more or less severe accident.

Method: Experiment 2 Laboratory experiment Independent design

Independent Variable: Experiment 2 Verb used in question: smashed hit no question – control group

Dependent Variable: Experiment 2 Estimate of speed Recollection of broken glass

Participants: Experiment 2 150 students three groups of 50 students

Procedure: Experiment 2 One film of traffic accidents was shown. Participants were given a questionnaire. Firstly, they had to describe accidents in their own words. Secondly, they had to answer some questions.

Critical question About how fast were the cars going when they hit each other? Other verbs substituted smashed The control group were not asked about speed.

Estimations of speed Smashed 10.46 mph Hit 8.00 mph

Procedure cont’d One week later the participants returned. They answered a series of ten questions with critical question embedded randomly.

Critical question Did you see any broken glass? NB: There was NO broken glass in the film.

Answer to question on glass Results: Experiment 2 Answer to question on glass Yes No Smashed 16 34 Hit 7 43 Control group 6 44

Conclusions Confirmation that the form of the question can significantly affect an eyewitness’s memory. This could be because: Memory consists of two pieces of information that gained at the moment of event that gained after the event Eventually both become one 'memory' severity of verb 'smashed' distorts the memory of event

Controls The same films were shown. The questions were all identical except for critical question. The critical question was embedded in other questions. There was random placement of critical question.