Eyewitness recall

This experiment investigated into the effect of ecological validity on eyewitness testimony, and was influenced by previous criticisms of research into eyewitness testimony, for example Loftus’ work was criticized because participants were not in a state of high emotion (as they would be at the time of witnessing a real crime) and experiments conducted involving real-life situations was generally based upon retrospective data, meaning recall may have been somewhat distorted. The experiment aimed to discover if there is a link between ecological validity (i.e. emotional arousal) and accuracy of recall.

As there is conflicting evidence regarding the effect of high emotion on recall (flashbulb memories vs. repression), the hypothesis chosen was non-directional and was simply that ecological validity would have a significant effect on recall. The research designs used were a laboratory experiment and a field experiment, and took place in an IT lab, where a video was shown to participants, and a classroom where a real argument was staged, in order to produce different levels of ecological validity for comparison. Due to time constraints, an opportunity sample of 20 grammar school girls aged 12-13 was used, in two groups as part of our independent measures design.

One group was shown a video of a staged argument between a girl and a teacher, and told they were taking part in a psychology experiment. They were then asked 10 questions, one of which was leading, relating to the scene they had watched. The second group witnessed the argument taking place in front of them and the girls were not aware they were part of an experiment. They were then told, and asked the same set of questions. Both sets of participants were fully debriefed. The independent variable was the environment, and the dependant was whether participants were correct in their answers.

The results obtained showed recall in situations of low ecological validity was slightly higher; these were analyzed using the Mann-Whitney U test in order to determine the level of statistical significance. Unfortunately, this showed that the possibility of the results occurring through chance was significantly greater than 5% (the critical value was 23 and ours was 38.5), and so the null hypothesis had to be accepted i.e. that ecological validity has no significant effect on recall. However, this may have been due to the size and selection of the sample used, the variety of questions asked, the fact that participants may have been able to confer or a number of other factors and therefore if the experiment was repeated, it is very possible a more significant result may be obtained.

Introduction Cognitive psychology is concerned with the human memory, and for my coursework I decided to investigate into a specific area of it: eyewitness testimony. This is an area of some debate as studies such as Loftus and Palmer (1974) have shown that witnesses are liable to change their stories when confronted with leading questions. In this study, students were shown clips of car crashes and then asked various questions, one of which was about how fast the cars were going on impact. For this, several different wordings were used; the cars were describes as having ‘hit’, ‘smashed’, ‘bumped’, ‘collided’ or ‘contacted’ each other to different students.

When later asked to estimate the speed at which the vehicles were traveling, significant differences were found depending on which word had been used. This led to Loftus and Palmer to conclude that either the participants were not sure of the answer to begin with and the question provided it for them, or the wording actually altered the memory representation, however a second experiment was unable to establish which explanation was correct. In the laboratory situation, the participants were aware they were being studied and this may have led to demand characteristics. In addition, the fact that the event witnessed was on film meant that they were not in a state of high emotional arousal and so a comparison between this and real-life events cannot be drawn. Loftus also conducted an experiment into the ‘weapons focus’ and found that while peripheral details are subject to forgetting or distortion, those that are central are remembered well.

However, several real-life studies have been conducted into the effects of leading questions on recall, such as Yuille and Cutshall (1986), who interviewed witnesses of shootings, and Christianson and Hubinette, who did the same with bystanders and victims of bank robberies. Both of these found that central detail shown that recall of central facts is unaffected and that only minor details are forgotten or distorted.

At the time of witnessing a crime, people are usually in a state of high emotion and evidence shows this has an effect on later recall. ‘Flashbulb memories’ are memories of specific important events of which recall of detail remains surprisingly good a long time after the event has taken place and are a popular theory first proposed by Brown and Kulik. Johnson and Scott conducted a laboratory experiment in which participants were subjected to either a high or low stress condition.

The high stress condition (witnessing a man coming out of a room holding a blood-covered letter opener) was assumed to cause sufficient emotional arousal for a flashbulb memory of the event and indeed found that some participants from this condition had better recall when asked to identify the man, however this was by no means true for all of them. An opposing theory of the effect of emotional arousal on recall is that of repression, when a person locks potentially disturbing or painful memories into the subconscious so they are not accessible, explaining why many victims of crime remember nothing of the event.

Studies of the effect of emotional arousal often use retrospective data so the memories may have already been distorted – there is no way of knowing. Many others take place in laboratories, eliminating this problem but these studies lack ecological validity and may yield demand characteristics. In an attempt to solve both these problems two experiments will be conducted, one in a field setting and one a laboratory to find out if ecological validity, i.e. the high emotional state that witnesses are in, has an effect on recall. Due to the fact that there is evidence for both flashbulb memories and repression, a two-tailed hypothesis will be more appropriate as preliminary research has shown that although ecological validity is likely to have some effect, it is unclear as to what this will be (whether it will increase or decrease recall.)

This research will be fairly similar in set-up to that of Loftus, with people watching a scene take place and then being asked questions about it. Her work on leading questions will also be brought in to determine if people’s susceptibility to these is different in the two situations by making one of the ten questions asked leading, although this will not be tested statistically and is simply an additional point of interest.

The aim of this study is to determine whether or not ecological validity, i.e. the high emotional state that people are in at the time of witnessing a crime, has an effect on recall in eyewitness testimony. The experimental hypothesis is that ecological validity will have a significant effect on eyewitness recall. The null hypothesis is that ecological validity will have no significant effect on eyewitness recall.

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