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Stress Helps Interrogators Spot Lies
> 6/11/2007 9:43:53 AM

Interrogation and lie detection have been at the center of numerous editorials and news stories over the last several years. Many have debated the efficacy and viability of a number of options, but usually clinical data is not part of the discussion. Some new work might change that. According to researchers at the University of Portsmouth in England, adding mental stress on interviewees can actually help investigators become human lie detectors.

Published by the Economic and Social Research Council and conducted by a team from the University of Portsmouth, 255 students and 290 police officers took part in a series of seven experiments. The students were asked to provide either falsified information or the truth in recorded interviews. The officers were then asked to decide whether or not the speakers were being honest, through their recommended methods in deception detection; which include speech and visual related cues. The results were less than favorable.

However when researchers added to the cognitive load by asking the participants to recite their story in reverse or perform other similar tasks, a significant amount of the officers were able to identify deception.

Professor Aldert Vrij explained this in a press release, saying:

"Certain visual behaviors are associated with lying, but this doesn't always work. Nor is comparing a suspect's responses during small talk. Lying takes a lot of mental effort in some situations, and we wanted to test the idea that introducing an extra demand would induce additional cues in liars. Analysis showed significantly more non-verbal cues occurring in the stories told in this way and, tellingly, police officers shown the interviews were better able to discriminate between truthful and false accounts."

Obviously, this is a clinical study, and does not necessarily reflect what happens in the field on a daily basis. Nevertheless, it is interesting to note that many researchers have been focussing on using different brain imaging techniques like fMRI to spot liars with mixed results. While this might be the future of lie detection, this team found that good old-fashioned human intuition is still a powerful lie detection tool. If the findings from this study hold true, we could see real improvement in the ability and training of interviewers to pick up cues and signals that indicate truthiness or even outright lying.

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