Reconstruction of automobile destruction
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Reconstruction of automobile destruction was a psychological study carried out by Elizabeth Loftus and John Palmer in 1974. The aim of the study was to investigate whether or not an eye witness's memory can be altered by information supplied to them after an event. Loftus and Palmer also wished to discover whether or not a person's memory can be influenced by this information.
Background to the study
The purpose of the study was to determine how memory is influenced by circumstances and prompting surrounding memory storage and recall. Previous studies had established that memories were not necessarily accurate representations of actual events but were actually constructed using past experiences and other manipulations
Two studies were carried out by Loftus & Palmer. The first was tested on forty-five students split into five categories, each with nine students. The second was carried out on one hundred and fifty students.
Method of study one
In the first study forty-five students from the University of Washington were shown seven film clips of car accidents. The clips ranged from five to thirty seconds long. After viewing each clip the students were asked to write a report on what they had seen. They were asked a series of questions about the videos. The critical question in this study was "At what speed was the car traveling?" The five categories of students were asked this question but with a different verb (shown below). Loftus and Palmer wanted to see if the verb influenced the students' (eye witnesses') answers.
- About how fast were the cars going when they collided with each other?
- About how fast were the cars going when they smashed into each other?
- About how fast were the cars going when they bumped into each other?
- About how fast were the cars going when they hit each other?
- About how fast were the cars going when they contacted each other?
Results of study one
Loftus and Palmer explained that the more severe the verb the more likely we are to estimate a higher speed. However they also argued that the findings could simply be due to a distorted memory caused by the verb that was used. They stated that some answers may have been due to a response bias meaning people who could not remember simply devised a made up answer.
Loftus and Palmer found that the more intense the verb used in the question, the higher the estimate of speed. The actual results were:
Smashed : 40.8 miles per hour
Collided : 39.3 miles per hour
Bumped: 38.1 miles per hour
Hit : 34.2 miles per hour
Contacted : 31.8 miles per hour
Method of study two
In the second study, one hundred and fifty students watched a one minute video clip which contained a four second scene of a multiple car pile-up. They were then asked a series of questions about the scene. The same question ("about how fast were the cars going...") was used but the students were also asked to return a week later to answer more questions. When they returned another critical question was asked: "Was there any broken glass at the scene?". In this study there were three groups of students. Each group was asked a different version of the question concerning the speed of the automobiles. One group was asked "About how fast were the cars going when they smashed into each other?", the second was asked "About what speed were the cars going when they hit each other?" and finally the last group were not asked the question about speed.
Results of study two
In study two Loftus and Palmer discovered that the intensity of the verb affected the students opinion on whether there was any glass on the scene. Actually there was no glass present but by challenging the students memory Loftus and Palmer influenced the students to believe otherwise. The actual results were:
Smashed : 16 students claimed they could remember seeing broken glass whereas 34 said there was none present.
Hit : 7 students remembered glass but 43 were correct in thinking there was none.
No Question: 6 students could recall broken glass and 44 could not.
From their study Loftus and Palmer concluded that the verb also played a part in the misperception of broken glass in the film.
- Loftus, EF; Palmer JC (1974). "Reconstruction of Automobile Destruction : An Example of the Interaction Between Language and Memory" (pdf). Journal of Verbal Learning and Verbal Behavior 13: 585–9. doi:10.1016/S0022-5371(74)80011-3.