Data from: The strategy of psychopathy: primary psychopathic traits predict defection on low-value relationships

Recent evidence suggests that psychopathy is a trait continuum. This has unappreciated implications for understanding the selective advantage of psychopathic traits. Whereas clinical psychopathy is typically construed as a strategy of unconditional defection, subclinical psychopathy may promote strategic conditional defection, broadening the adaptive niche of psychopathy within human societies. To test this, we focus on a ubiquitous real-life source of conditional behaviour: the expected relational value of social partners, both in terms of their quality and the likely quantity of future interactions with them. We allow for conversational interaction among participants prior to their playing an unannounced, one-shot prisoner’s dilemma game, which fosters naturalistic interpersonal evaluation and conditional behavior, while controlling punishment and reputation effects. Individuals scoring higher on Factor 1 (callous affect, interpersonal manipulation) of the Levenson Self-Report Psychopathy Scale show two forms of conditional defection: one after being interrupted more frequently during the conversation, the other after failing to discover cues to future meetings with an interlocutor. Both interaction effects support the hypothesis that primary subclinical psychopathy potentiates defection on those with low expected relational value. These data clarify the function and form of psychopathic traits, while highlighting adaptive variation in human social strategies.