Using Thermal Imaging to Detect Deception Following a Staged Theft

Abstract

We conducted an experiment to test whether thermal imaging could detect deception. Half of the participants (n = 42) were randomly assigned to be “thieves” by stealing money from an unattended briefcase. The other half (n = 41) were randomly assigned to be “innocent suspects.” Immediately after the simulated theft, we interrogated all participants, although we instructed them to deny any involvement in the theft. During the interrogation, we measured each participant’s facial temperature using a consumer-grade, infrared thermometer. We hypothesized that lying would produce physiological reactions resulting in elevated skin temperatures. Although nearly all group means showed that thieves had higher skin temperatures than innocent suspects, most of the differences were not statistically significant. However, we found that thieves had statistically significantly higher skin temperatures when asked about the actual amount of money that was stolen. Thus, we found that thermal imaging was able to detect that thieves had concealed information regarding the mock crime. Thieves also reported statistically significantly more anxiety from the beginning to the end of the interrogation.