Yarmey set out to test eyewitness recall and ability to identify a target person from a photographic line-up in a field experiment, as previous research was mostly carried out in lab expts. Yarmey also wanted to test the effect of preparation/time lapses/disguises, etc. on identification/recall; and to investigate how accurate EWT was thought to be among students.
There were 215 male and 375 female participants, ranging in age from 18-70. Only white participants were used to avoid any race bias. Participants were randomly assigned to one of many different conditions listed below:
- being prepared (told that they were going to be an eyewitness) or not
- a disguise present (sunglasses and baseball cap) or not
- retrieval instructions enhanced or not
- tested immediately or delayed by 4 hours
- the gender of witness (male or female)
- whether the target was present or not in a line-up
Two white women were the targets (to be identified).
Participants were approached by a target in a public place and asked to help look for lost jewellery or asked for directions. After 2 minutes a female researcher went up to the participant and asked him or her to take part in the study. The researcher either asked then and there about the identification of the target or 4 hours later. Witnesses were given a questionnaire with 16 items, 8 about the physical characteristics of the target and 8 about her clothing. They rated their confidence about their answers on a 7-point scale. After completing the questionnaire witnesses were given a set of 6 photos. In half the cases the target was present in the photos, and in half the target was absent. Participants were asked to identify the target female (they were told she may or may not be in the photos, and they were shown each photo only once). At the end of the study there was a debriefing.
Another part of the study was to give the whole scenario in written form to students. The students were asked to comment on what they thought would happen and what would affect eyewitness recall.
In many cases significant differences were found between the various conditions.
When the target was present in the photo line-up, about 49% of participants correctly identified the target, and 62% correctly said that the target was not there in the 'target absent' condition.
It is interesting to compare the findings about the correct identification in the photo line-up with the student predictions.
- it was found that where 62% of the participants correctly said the target was absent in…