pychology

RECONSTRUCTION OF AUTOMOBILE DESTRUCTION.

Theories on which study is based:

• Schema theory proposes that memory is influenced by what an individual already knows, and that their use of past experience to deal with a new experience is a fundamental feature of the way the human mind words.
• Knowledge is stored in memory as a set of schemas - simplified, generalised mental representations of everything an individual understands by a given type of object or event, based on their past experiences.
• The schema forms part of Bartlett's theory of reconstructive memory, which forms the basis for Loftus and Palmers study into EWT.

Background:

• memory involves interpreting what is seen or heard, recording bits of it and then reconstructing these bits into memories when required.
• This implies that recall can be distorted or biased by certain features of the situation.
• This study focuses on the effects of leading questions on memory.

• Cognitive processes include how we attain, retain and regain information, through the process of perception, attention, memory, problem solving, decission making, language and thought.
• This study is concerned with Eye Witness Testimony (EWT) and shows that memory is reconstructive.
• Bartlett's (1932) theory of reconstructive memory proposes that individuals reconstruct the past by fitting new information into their existing understanding of the world - a schema.
• Loftus and Palmer showed that EWT is influenced by peoples tendency to reconstruct their memories of events to fit their schemas.

Experiment 1:

• Both were a lab experiment using an independent measures design.
• The IV was the wording of a critical question hidden in a questionnaire.
• The question asked was: "About how fast were the cars going when they hit/smashed/collided/contacted/bumped eachother?"
• The DV was the estimated speed given by the participant.

Experiment 2:

• The IV was the wording of a question in a questionnaire:

      - One group was asked "About how fast were the cars going when they hit each other?"

      - A second group was asked "About how fast were the cars going when they smashed into eachother?"

      - A third group was not asked about the speed.

• A week later all the participants were asked "Did you see any broken glass?" 
•  DV was yes or no.

• 45 students were divided into 5 groups, with 9 in each group.
• All participants were shown the same clip of different traffic accidents which were originally made as part of a driver safety film.
• After each clip, participants were given a questionnaire, which asked them first to describe the accident and then to answer a series of questions about the accident.
• There was one critical question in the questionnaire: "About how fast were the cars going when they smashed/ colided/ hit/ contacted/ bumped eachother?"

• 150 students were divided into 3 groups.
• All participants shown a 1-minute film which contained a 4- second multiple car crash.
• They were given a questionnaire, which asked them to describe the accident and answer a set of questions about the incident.
• There was a critical question about speed:

      - One group asked: "About how fast were the cars going when they smashed into eachother?"

      - Another group asked: "About how fast were the cars going when they hit eachother?"

      - The third group didn't have a speed quesiton.

• One week later all participants, without seeing the film again, completed another questionnaire about the accident, this has another critical quesiton: "Did you see any broken glass- Yes/ No?"
• There hadn't been any broken glass in the film.

                                         Verb                   Mean Speed Estimate(mph)

                                          Smashed                            40.8

                                          Collided                              39.3

                                          Bumped                              38.1

                                          Hit                                       34.0

                                          Contacted                           31.8

• "Smashed" produced highest speeds and "contacted" produced the slowest.
• The film of a crash at 20mph was estimated to be 37.7mph.
• The film of a crash at 30mph was estimated to be 36,2mph.
• The films of crashes at 40mph were estimated to be 39.7mph and 36.1mph.

Verb       Mean Speed Estimate(mph)

                                              Smashed      10.46

                                              Hit                  8.00

• "Smashed" produced the highest speed estimates.

Response     Smashed     Hit     Control

                                                  Yes              16             7           6

                                                  No                34           43         44

• More participants in the "smashed" conditon than either the "hit" or control groups reported seeing broken glass.
• The majority of participants in each group correctly recalled that they had not seen any broken glass.

Conclusions.

• The verb used in the question influences a persons response- that is, the way a question is phrased influences the answer given.
• People are not very good at judging vehicular speed.

Usefulness.

• Based on findings such as these, the Devlin report (1976) recommended that trial judges be required to instruct the jury that it is not safe to convict on a single eyewitness testimony, except in excpetional circumstances or when there is substantial corroborative evidence.
• The recommendation was rejected by the judiciary and the Home Office, but juries are now warned of the dangers of honest mistakes by eyewitnesses.