Deception detection: Criminals’ beliefs and performance

Abstract: This thesis examines criminals’ beliefs about cues to deception (Study I), and their ability to distinguish between truthful and deceptive statements (Study II). The rationale for studying this group is that there may be reason to believe that criminals inhabit a more beneficial environment for gaining insights into the psychology of deception. Plausibly and in accordance with the so called feedback hypothesis, they receive more outcome feedback on their deception judgments, as well as on their own deception performance. This notion received some support in the studies. Study I is a survey examining beliefs about cues to deception held by 107 prison inmates, 103 prison personnel and 116 students. In line with the ideas about more beneficial learning structures in the environment of criminals, and findings from previous studies, it was predicted that the beliefs held by prison inmates would be relatively more consistent with pattern found in studies on actual cues to deception. It was found that, in line with previous surveys on beliefs about deception, students and prison personnel held stereotypical and wrongful beliefs about indicators of deception. The beliefs of prison inmates were less stereotypical than the beliefs of the other two groups. In Study II, which is a quasi-experiment, the deception detection accuracy of 52 prison inmates and 52 college students was examined. The participants made veracity judgments of videotaped statements of witnesses either lying or telling the truth about an event. In line with the findings from previous research as well as with theories on intuition and expertise, it was predicted that prison inmates would outperform students in terms of lie detection accuracy. This prediction received partial support, since prison inmates achieved an accuracy rate higher than chance, while students did not. Furthermore, prison inmates had a pronounced lie bias. Taken together, the two studies indicate that outcome feedback may be an important component in the development of valid knowledge about deception and its detection.