CRIMINAL CLASSIC STUDY: LOFTUS AND PALMER (1974) - Coggle…
CRIMINAL CLASSIC STUDY: LOFTUS AND PALMER (1974)
To investigate how information supplied after an event (in the form of a leading question) influences an eyewitness' memory for that event.
Each shown the same 7 film clips of traffic accidents.
Ranged from 5-30 seconds long
Then asked to write an account of the accident they had just seen and asked to answer some specific questions, one of which was the critical question, to do with the speed of the vehicles involved in the collision.
5 conditions in the experiment each with 9 ppts, and the IV was manipulated by means of wording of the questions. The condition depended on the word the ppts heard when being asked the critical question.
Critical question: "About how fast were the cars going when they smashed/collided/bumped/hit/contacted each other?"
The entire experiment lasted about an hour and a half and a different ordering of the films was presented to each group of ppts.
SAMPLE : 45 students (opportunity sample)
Mean speed given for each of the different verbs:
smashed: 40.8 mph
collided: 39.3 mph
bumped: 38.1 mphhit: 34.0 mph
contacted: 31.8 mph
These results show that the phrasing of the question brought about a change in speed estimate. The verb 'smashed' elicited a higher speed estimate that the verb 'contacted'.
Study provided evidence of the effect that post-even information can have on the recall of that event.
But didn't know whether this was because the information in the question biased a person’s response or actually altered the person’s memory of the event. → Second experiment was conducted to see which was the case.
P: Loftus and Palmer’s experiments were well-controlled.
E: The laboratory setting enabled strict control of variables: the only change that ppts experiences were the wording of the critical question in each case. The content of the interviews was standardized for each participant, as was the video clip.
T: This suggests that the experiment has high internal validity and is replicable, meaning it can be repeated to test for reliability.
P: The laboratory setting reduced the external validity.
E: Watching a car crash on video is a very different experience from witnessing a similar one even in real life. A film clip is unlikely to elicit the same level of emotional strain as a real crash. Similarly, there is not the same emotional investment, there is no risk of someone going to prison should be the estimate of speed be incorrect.
T: Therefore, Loftus and Palmer’s study lacks mundane realism.
P: A weakness is that Loftus and Palmer’s sample may have been unrepresentative.
E: The participants were college students . Their level of education may have affected the results as more intelligent individuals are likely to make better witnesses. Or students may have less experience of driving a car and this may have affected their judgement of speed. Either way, a student sample is not representative of the general population.
T:The biased sample may have reduced the generalisability of Loftus and Palmer’s findings.
P: There are studies that have indicated that eye-witness testimony can be very reliable.
E: A study by John Yuille and Judith Cutshall (1986) showed that witnesses to a real-life gun shooting in Canada gave very accurate reports of the crime four months after even though they had initially been given two misleading questions.
T: This suggests that in real situations (when the sakes may be higher), witnesses are less influenced by post-event information.
P: Loftus’ work on eye-witness testimony led to a review of the legal system.
E: Research into eye-witness testimony and the fallibility of human memory was a major consideration in the Devlin Report, published in 1976. Among the recommendation was that juries should not convict on the basis of a single eye-witness statement. Also, Loftus’ work arguably contributed to changes in the way the police questions witnesses.
T: This shows that Loftus’ work has implications that stretch beyond the laboratory.
ISSUES AND DEBATES
P: This study illustrates how psychological understanding changes over time.
E: Loftus has produced a prolific body of work into the nature of memory. Her focus has changed over the years, and in the 1990S she became more concerned with whether it was possible to implant lase memories for entire events that had never taken place. This led to her involvement in a number of high profile and controversial legal case, debating whether supposed ‘recovery memories; of childhood abuse were in fact false memories suggests during therapy.
T: This led to stricter controls on the use of recovered memories in court.
Ps were shown a short (1 minute) film which contained a 4 second scene of a multiple car accident, and were then questioned about it.
There were 3 conditions and the IV was manipulated by the wording of the question.
50 Ps were asked:"How fast were the cars going when they hit each other?"
50 Ps were asked"How fast were the cars going when they smashed into each other?"
50 of the Ps were not questioned about the speed of the vehicles, they were a control group.
One week later, the Ps returned and were asked a series of questioned about the accident they viewed the week before.
The critical question here was, "Did you see any broken glass?".
The DV was whether or not the Ps said they has seen the broken glass.
note: there was NO broken glass in the clip.
SAMPLE: 150 students
Those in the ‘smashed’ condition’:
gave the highest estimate of speed
were significantly more likely to report seeing broken glass.
16 reported seeing broken glass in the film, where as only 7 did in the ‘hit’ condition and 6 in the control condition.
Findings suggest that the post-event information did not simply create a response bias.
It actually altered the person’s memory of the event and generated expectations, such as the likelihood that there would be broken glass.