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Individual differences |
Methods | Statistics | Clinical | Educational | Industrial | Professional items | World psychology |
- Main article: Witnesses
Eyewitness memory refers to the episodic memory of specific event, often a crime. Eyewitness memory, which is relied upon in the process of eyewitness identification, is thought to be fragile and easily distorted by information obtained post-event.
Fragility of eyewitness memoryEdit
Vulnerability to post-event distortionEdit
- See also: Interference theory
As with all memories, eyewitness memories can be distorted by what we previously knew (proactive interference) or what we learn in the future (retroactive interference). The distortion of memories by these means has been widely studied in relation to interference theory.
In the case of eyewitness memory, retroactive interference perhaps as a result of police questioning, can lead to difficulty in accurate recall.
A 1974 study by Loftus and Palmer suggests that eyewitness memory is highly vulnerable to post-event distortion. Participants were presented with photographic slides of a multiple-vehicular accident. Experimental group participants were then asked either "About how fast were the cars going when they smashed into each other?" or "About how fast were the cars going when they hit each other?". Participants were questioned a week later as to whether they had seen broken glass in the photographic slides. Although no broken glass was in actuality present in the slides, 32% of participants originally asked if the cars had "smashed into each other" reported they had. This was in comparison to only 14% of those asked if the cars "had hit each other," the conclusion being that the information in the question affected recall of the event.
Verbal overshadowing of visual recallEdit
- Main article: eye witness testimony
It has been suggested that verbal reports may interfere with visual recall of an event. This was concluded by Schooler and Engstler-Schooler following their study in 1990. Participants in this study initially viewed a video recording of a crime. Subsequently one group of participants made a detailed verbal report of the physical appearance of the criminal whilst the other group performed an unrelated task. All participants then were asked to visually identify the criminal. The group which made the verbal report performed significantly worse in this final visual identification task.  Subsequent research has largely replicated these findings by Schooler et al. although alternative conclusions have been made. 
Eyewitness Memory Reconstruction Edit
The account of an event is thought of as concrete information. It is commonly believed that one will experience an event, which is then placed into the long-term memory. Subsequently, when asked a question about that particular event, one will quickly recall that intact memory back out of the long-term memory and report it exactly as is. However, through the study of cognitive psychology, psychologists have began to question the accuracy of these eyewitness accounts. One such psychologist, named Elizabeth Loftus at the University of Washington, has espoused a new theory regarding the accuracy of eyewitness accounts due to a series of experiments she completed. Loftus argues that the memory of an event is placed into long-term memory and is then reconstructed after the fact due to instances such as verbalization of the event, pictures, discussion, other life events that may be a reminder of that specific event, or even the nature of a question asked about the event that may suggest nonexistent occurrences. After this particular memory is reconstructed, if asked to recall the event, one then pulls that new reconstructed memory from the long-term memory and it is then used as a factual recollection. This reconstruction is usually subtle and harmless, unless, of course, a person is in a situation where his or her recollection could change the fate of another person’s life due to their account of an event. Because of this potential threat to our current judicial system, Loftus constructed a four-part experiment in order to support and accurately construct her present theory. The purpose of these experiments were to measure the power of questions and to find whether or not the way a question is asked leads to the false reconstruction of memory. Loftus hypothesized that the power of a question is significant regarding the long-term reconstruction of an event. good example of how memory may be constructed based on the nature of the question, according to the hypothesis of Loftus's experiment, is this: If you are driving to work one day and a car crash takes place in front of you, later, while in court as an eyewitness, a defense attorney may ask, “How many people were in the car when they ran the red light which ultimately led to this accident?” Because the subject of the question concerns the amount of people, the eyewitness may subconsciously accept the claim that the car did in fact run the red light. Then, when asked later whether or not the car ran a red light before crashing, that person’s response is more likely to be, “Yes, the car did in fact run the red light.”
The Experiment(s) Edit
The purpose of Experiment 1 was to find whether or not the nature of a question could make one more likely to be confident that they saw something that may not have been there in actuality. For Experiment 1, 150 students were presented a short viewing of a five-car pileup after one car runs a stop-sign into oncoming traffic. The accident takes place within four seconds, the entirety of the movie lasting less than a minute. Shortly following the video, the students were all given a 10 question survey. These surveys were split into two groups in which the only difference is the first question. For the first group, question number one contained the question, “How fast was Car A (the car that ran the stop sign) going when it ran the stop sign?” However, for the second group of surveys, the question was “How fast was Car A going when it turned right?” The next eight questions were considered “filler” questions, then for the tenth collective question the survey asked, “Did you see a stop sign for Car A?” The results of this experiment were that out of all the people who took the first set of surveys, when asked whether or not there was a stop sign, 40 answered that they did see a stop sign for Car A whereas out of the people in the second group, only 26 answered that they did not see one. That is 53% vs. 35%, a significant enough difference to infer that the nature of the question could in fact reconstruct ones memory. The purpose of Experiment 2 was to find whether or not the surveys would have a persisting effect on the correct recollection of an event. For Experiment 2, there were 40 subjects presented with a clip (length: 3 minutes), from the film Diary of a Student Revolution. In this clip, 8 demonstrators interrupted a classroom. The 40 subjects, shortly after viewing the film, were given a survey to take which included 20 questions. Again, the surveys were split into two groups in which question number one for the first group reads, “Was the leader of the 4 demonstrators who entered the classroom a male?” and question number one for the second group reads, “Was the leader of the 12 demonstrators who entered the classroom a male?” The other nineteen questions were filler questions, used to deter the focus of the number of demonstrators to see whether or not the false number in the question would alter the subject’s memory. The experimenter then left the subjects alone for one week, later asking them, “How many demonstrators did you see entering the classroom?” The first group, on average recalled that they had seen 8.85 demonstrators whereas the second group recalled an average number of 6.40 demonstrators. After the fact, very few recalled the actual number of demonstrators, therefore proving that one question that assumed a false number caused the subjects to reconstruct their recollection of that particular three minute clip of a film. The purpose of Experiment 3 was to find whether or not a question could cause a person to construct an object or action that was not even an original part of the event. Experiment 3 consisted of 150 university students used as subjects, presented with a video consisting of an accident involving a white sports car followed by a 10 question survey. Again, these surveys were split into two different groups, one question being “How fast was the white sports car going when it passed the barn while traveling along the country road?” while the other was, “How fast was the white sports car going while traveling along the country road?” As you can see, the question in Group A mentioned the presence a barn while the actual event did not take place within sight of one. Again, the next eight questions were "filler questions, and the tenth question was the same for both groups asking “Did you see a barn?” Interestingly enough, 13 people, or 17% of Group A recalled there having been a barn whereas only 2, or 2.7% of Group B responded in the same way. Experiment 4 elaborated on the effects of all of the previous experiments, also adding a new aspect to the study. Loftus wanted to find out whether or not somebody, after being asked a question with an imaginary object or aspect, is more likely to remember that object or aspect as having happened after a certain amount of time has passed since the event. There were 3 groups; D, F, and C, each with 50 subjects. These three groups were given varying packets containing different questions about an event that was played for the people. The event was a camera inside of a car, colliding with a man pushing a baby carriage. Group D was given a packet of 40 “filler” questions in addition to the following questions: “Did you see a school bus in the film?” “Did you see a truck in the beginning of the film?” “Did you see a center line on the country road?” “Did you see a woman pushing the carriage?” and “Did you see a barn in the film?” Group F was given a packet with the same 40 questions in addition to the following questions: “Did you see the children getting on the school bus?” “At the beginning of the film, was the truck parked beside the car? “Did another car cross the center line on the country road” “Did the woman pushing the carriage cross into the road?” and “Did you see a station wagon parked in front of the barn?”. Finally, group C was given only those same 40 questions because it was the control group. The three groups were then given one week before the subjects came back to answer 20 more questions about the event. Group D’s packet remained exactly the same while the other Group’s questions changed. The results of the study were that the percentages of people who replied, “yes” to these questions after one week were as follows: Group C (8.4%), Group D (15.6%), and Group F (29.2%). All of the people who answered “yes” to these questions were wrong in their recollection of the event meaning that their memory had in fact been reconstructed significantly as a result of the experiment.
While these four experiments cannot prove that in all cases people reconstruct their memory falsely, there is significant evidence in all cases which enables cognitive psychologists to infer, or at least look into, the fact that perhaps Loftus has a solid and valid point that there were a sufficient amount of people in her experiment who reconstruct their memories falsely due to outside influence. Therefore, this experiment implores psychologists to reevaluate their basic principles about memory and urges cognitive psychologists to elaborate on the sparse research implemented regarding the accuracy of eyewitness accounts.
- ↑ Principles of Cog. Psychology, Eyesenck, M.W. 2nd ed (2003), pp229
- ↑ Principles of Cog. Psychology, Eyesenck, M.W. 2nd ed (2003), pp221
- ↑ PsychExchange.co.uk
- ↑ Principles of Cog. Psychology, Eyesenck, M.W. 2nd ed (2003),p222
- ↑ http://digitalcommons.utep.edu/cgi/viewcontent.cgi?article=1007&context=christian_meissner
- ↑ Loftus, E. (2002),Memory Faults and Fixed, Issues in Science and Technlolgy, Summer, 2002, pp. 41-50
Key texts – BooksEdit
- Lindsay, R.C.L., Ross,David F., Read,J. Don , and Toglia, Michael P. ( 2007) (eds)The Handbook of Eyewitness Psychology. Vol 1:Memory for Events. Lawrence Erlbaum Associates ISBN 978-0-8058-5151-9
- Lindsay, R.C.L., Ross,David F., Read,J. Don , and Toglia, Michael P. ( 2007) (eds)The Handbook of Eyewitness Psychology. Vol 11:Memory for People. Lawrence Erlbaum Associates ISBN 978-0-8058-5152-6