McCaffrey, Marlene

Poster presented at the Human Behavior and Evolution Society Meeting (2016), Vancouver, Canada.<p>We investigated the relationship between hormones, the Dark Triad traits (i.e., Machiavellianism, psychopathy, and narcissism), the ability to deceive others, and the ability to detect deception. Video recordings of multiple statements (i.e., either true or lies), self-reported Dark Triad scores, and saliva samples (pre- and post lies) were obtained from male and female undergraduates. An mTurk sample watched the target videos and judged which statement they believed to be a lie. Among raters, higher psychopathy scores were associated with better lie detection abilities. Targets who were higher on the Dark Triad traits were the best liars (regardless of gender), while the female target who was low in the Dark Triad traits was the worst liar. Among women, higher scores for Machiavellianism and psychopathy were related to decreases in Testosterone and Cortisol after having to lie on video, while the pattern was reversed for males. Results are discussed in terms of adaptive benefits of individual difference variation, and the cheater detection hypothesis.

In order to test the cheater hypothesis in relation to the Dark Triad traits (i.e., psychopathy, narcissism, and Machiavellianism), we conducted (N = 25 men) a pre- and post-test assessment of testosterone and cortisol with a social evaluative stress (i.e., lying while being video-taped) in between. Machiavellianism was positively correlated with pre-test testosterone, while psychopathy and Machiavellianism were positively correlated with pre-test cortisol. Cortisol decreased in men who were higher in Machiavellianism immediately after completing the lie-task and the patterns for narcissism and psychopathy were in the same direction, suggesting that these individuals were less stressed after the two truths and a lie task. Testosterone increased in those high in psychopathy and narcissism post-task, possibly reflecting, at least among narcissists, their enjoyment of the challenge to deceive others. Results provide physiological support to the hypothesis of the Dark Triad traits represent a “cheater strategy”.