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Reconstruction of Automobile destruction. Elizabeth F. Loftus and John C. Palmer (1974). Please read the title and look at the picture. Try to remember both. Curtains in a window. Bottle. Crescent moon. Beehive. Eye-glass. Seven. Ship’s wheel. Hour glass. Kidney bean. Pine tree. Gun.
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Reconstruction of Automobile destruction Elizabeth F. Loftus and John C. Palmer (1974)
Please read the title and look at the picture Try to remember both
Please read the title and look at the picture Try to remember both
Please draw as many of the pictures as you can • Please write ‘1st group’ or ‘2nd group’ on your paper
Experiment • Please hand your drawing to a member of the other group • Check to see whether the drawing looks like one of a pair of objects
Curtains in a window or Diamond in a rectangle Bottle or stirrup Crescent moon or letter “C” Beehive or hat Eye-glass or Dumbbells Seven or Four Ship’s wheel or Sun Hour glass or Table Kidney bean or Canoe Pine tree or Trowel Gun or Broom Two or Eight
Reconstruction of Automobile destruction Elizabeth F. Loftus and John C. Palmer (1974)
Theory • People are not good at reporting numerical details, such as time, speed and distance (Bird 1927). • Marshall (1969) found that participants gave speed estimates ranging between 10 and 50 mph for a car travelling at 12mph!
Theory • (Block 1974) Because people are poor at estimating they can be easily influenced by questioning, for example. In courts of law leading questions can not be asked. • Fillmore (1971) found that the words `hit' and `smashed' could affect the estimated speed.
Experiment 1Method • 45 students in groups of various sizes • Would the results generalise? • Are they just trying to please their teacher?
7 films from the local safety council and police • 5 - 30 second film clips, of car accidents. • Not really like a real accident, therefore lacks ecological validity • After a written account of each accident was given by each student, a series of questions was asked. • The critical question was one about the estimated speed of the vehicles.
Experiment 1 - Method • What was the purpose of the written account? • Did this affect the results? • Loftus & Palmer fail to report any details of what was written • What data could have been obtained from these accounts?
Experiment 1 - Method • 5 groups of 9 students. • Group sizes rather small • Between 15 and 20 in each group is usually sufficient • Each group had a different version of the critical question.
Experimental Conditions • 1. About how fast were the cars going when they hit each other? • 2. About how fast were the cars going when they smashed each other? • 3. About how fast were the cars going when they collided with each other? • 4. About how fast were the cars going when they bumped into each other? • 5. About how fast were the cars going when they contacted with each other?
Independent Variable • Different wording of the questions
Dependent Variable • Speed estimates
Experiment 1 - method • The time taken to conduct the experiment was about one hour and a half. • Films were presented to the participants in different orderings
Experiment 1 - Results • These differences are significant at p is less than 0.005. • This means that less than five in every thousand times this experiment is run could the results possibly be owing to chance factors • As chance results are unlikely we reject our null hypothesis
Experiment 1 - Hypothesis • It is predicted that there will be a significant difference between speed estimates depending upon the verb used in the question about speed. • This is known as a two-tailed experimental hypothesis because we are just predicting a difference without saying which verb has the greatest effect on speed estimation.
Experiment 1 - Did the actual speed of the cars affect the estimate
Experiment 1 - Discussion • 1. The participant is not sure of the speed so the verb provides the answer. • 2. The verb changes the memory representation.
