Can individuals accurately identify high Machiavellians as low cooperative based on facial appearance? The moderating role of target gender and raters' Machiavellianism

Accurate detection of counterpart cooperativeness is vital for human survival and development. However, whether people identify high Machiavellians, who intend to defect their counterparts in cooperative situations, as uncooperative is unknown. This study examined whether the general public could identify differences in cooperativeness between high and low Machiavellians based on their facial appearance, as well as the boundary conditions of this effect. Two experiments were conducted. Participants were asked to rate the cooperativeness of targets, including men and women with high and low Machiavellianism, shown on real facial photos created in a preliminary experiment (Experiments 1 and 2), and report their own Machiavellianism level (Experiment 2). Results consistently showed that the participants identified high Machiavellians as less cooperative than low Machiavellians. Moreover, we also identified two theoretical moderators: the effect only existed when the targets were male but not when they were female, and the effect was stronger when the raters were low Machiavellians as opposed to high Machiavellians. This study advances the current understanding of cooperation detection by demonstrating that people could reliably identify the low levels of cooperativeness of high Machiavellians based on facial appearance cues, and by comprehensively testing its moderators.