Yarmey (2004)

Aims

To look at the effect of being part of a field experiment related to eyewitness recall and photo identification, and how a disguise would affect retrieval. He also wanted to see if instructions given before recall to review the incident would affect identification and to see the effect that a 4 hour time gap could have.

Procedure

There were 215 male pps and 375 female pps aged 18-70. They only used white pps to avoid any racial bias and the pps were randomly assigned to one of the following conditions:

  • Being told they would be an eyewitness or not
  • A disguise was present or not
  • Retrieval instructions enhance or not
  • Tested immediately or after a 4 hour delay
  • Gender of the witness
  • Whether the target was or wasn’t present in a photo line up

The targets that the pps had to identify were 2 white women.

Pps were approached in a public place and asked to help look for lost jewellery or for directions. After 2 minutes a female researcher approached the pp and asked them if they would take place in a study.

They were asked about the identification of the target with a questionnaire formed of 16 questions – 8 about physical characteristics of the target and 8 about clothing. They then had to rate their confidence about the answers on a 7 point scale.

Then the pps were given 6 photos. Half of the time the target was present and the other half they were not. Pps were asked to identify the female target and were told she might not be present, having been shown each photo only once. Then they were debriefed.

Results

When the target was present 49% of pps identified her and when she wasn’t there 62% of pps correctly said that she wasn’t.

Students thought that the woman would correctly identified as missing 47% of the time and correctly identified as present 63% of the time.

Those who were prepared for the test were better at recall of events, but they were worse when it came to identification.

Conclusions

About 50% of the time a witness makes a correct identification in a line up when the target is present which fits in with the results of Haber and Haber’s meta-analysis.

It casts doubt on the assumption that EWT and identification is accurate. The students who had to estimate the accuracy were inaccurate which means that jurors were equally as likely to be inaccurate.