Loftus & Palmer (1974) - Study on Eyewitness Testimony

What is the aim of this study?

To investigate how information supplied after an event, influences a witnesses memory of the event

What is the IV for experiment 1?

The verb used during the critical question

What is the DV for both experiments?

The speed estimates in MPH (participant's response)

What is the design for this experiment?

Independent measures

What is the experiment type for this experiment?

Laboratory experiment

What is the method for experiment 1?

Participants shown 7 video clips of staged car crashes, were asked the critical question during a questionnaire, the verb used was dependent on the group they were assigned

What was the critical question?

“How fast were the cars going in MPH when they smashed/bumped/collided/hit/contacted each other?"

What are the results for experiment 1? (mean speed estimate in MPH)

Smashed- 40.5

Collided- 39.3

Bumped- 38.1

Hit- 34.0

Contacted- 31.8

What is the IV for experiment 2?

Verb used (smashed/hit)

What is the method for experiment 2?

Split into 3 groups who watched a singular clip, and 2 were asked critical question (either hit/smashed).

A week later, they were asked to fill in another questionnaire which included the question: “did you see any broken glass?” (real answer was no)

What are the results for experiment 2? (Speed, answered yes/no to broken glass)

Smashed- 10.46 MPH, yes (16), no (34)

Hit- 8 MPH, yes (7), no (43)

Control- yes (6), no (44)

Who were the participants for experiment 1?

45 uni students - split into 5 groups

Who were the participants for experiment 2?

150 uni students - split into 3 groups of 50

What conclusions can be made?

The phrasing of a question will enormously influence the answer that is given

Information obtained after the event can cause the memory to be modified