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Comparison of dog teams and polygraph in detecting "Guilt"

University of British Columbia

A study was conducted to evaluate the ability of police dog teams to identify "guilty" subjects in a simulated crime situation and to compare their accuracy with that of a polygraph examination. Research on the olfactory acuity of dogs, and on the role of olfactory cues such as pheromones in social communication, implies that the detection of guilt by experienced police dogs could occur as reliably as police dog handlers believe. The literature on polygraph investigations shows high reliability in detecting guilt. This was one of the reasons for using the polygraph as the comparison technique. Three experienced dog teams from the Vancouver Police Dog Squad and two expert polygraph field examiners were used. The subjects were 64 male volunteers, all university or college students. Subjects randomly assigned to the "guilty" condition were instructed to "steal" and conceal a $10 bill that had been left in an empty office, and to deny throughout the rest of the experiment that they had done so. Volunteers in the "not guilty" condition were told nothing about the "crime" Both groups were told that police dog teams and polygraph operators would try to find out whether they were guilty. They were promised $5.00 for participating plus a bonus of $10 if they succeeded in establishing that they were innocent. Police dog team performance was about chance level, while the polygraph examination was significantly more accurate than chance and than the dog teams. No individual difference was found among the dog teams. The failure of the dog teams could be attributed either to the impossibility of detecting guilty by smell cues or to some aspect of the simulation procedure. Further research should be directed at developing more realistic field studies.

Text

2010-02-26

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http://hdl.handle.net/2429/20991

Psychology

University of British Columbia

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