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Judging eye-witness accuracy
Suppose you were in court or conversing with a person who was giving an eye-witness account of an accident. The person seems genuine and seeks to tell what they saw, but are they remembering accurately? Are they embellishing the raw facts? Researcher Torun Lindholm investigated this ability in judges, police detectives and lay people.
Lindholm presented his subjects with videos of eye-witness statements about a kidnapping, then asked them to decide whether the witnesses were telling the truth or not. Worryingly, judges could not tell the differences. Unsurprisingly, neither could the general public. But rather reassuringly the police detectives were quite good at spotting the truth and not. So what was the difference?
All groups reported using the same cues to make judgements, including the difficulty of questions put to witnesses, the plausibility of the witnesses' answers and the witnesses' apparent confidence in their answers.
The assumption was that the police officers were able to pick up on subtle additional clues, such as non-verbal or language differences.
An interesting extra finding was that when the witness responses were
presented as written transcripts, the judgement accuracy went up! The
implication of this is that the observers were focusing on unreliable cues,
inexpertly reading non-verbals.
Torun Lindholm (2008). Who can judge the accuracy of eyewitness statements? A comparison of professionals and lay-persons. Applied Cognitive Psychology, 22 (9), 1301-1314.