Cues to Paternity: An Evaluation of Offspring Resemblance, Partner Fidelity, and Maternal Perinatal Association

Despite the profound influence of relatedness on mating and cooperative behavior in humans, the cues men use to assess paternity and guide offspring-directed behavior have yet to be fully resolved. According to leading theories of kin detection, kinship cues should influence both sexual and altruistic motivations, because of fitness consequences associated with inbreeding and welfare tradeoff decisions, respectively. Prior work with paternity assessment, however, has generally evaluated candidate cues solely by demonstrating associations with altruism. Here I (i) replicate past work that found effects of phenotypic resemblance and perceived partner fidelity on offspring investment; (ii) evaluate whether these two cues meet the more stringent criteria suggested by theory—that is, whether they predict both altruistic motivations and inbreeding aversions; (iii) propose and test a novel candidate cue to paternity: observations of maternal-infant perinatal association (MPA); and (iv) examine whether the significant effects of empirically validated kinship cues on altruistic and sexual motivations are mediated by reported certainty of relatedness. I conduct these tests using existing datasets, one from a population-based sample of Finnish fathers (N = 390), the other a Mechanical Turk sample (N = 744). Results provide the strongest evidence yet assembled in support of perceived partner fidelity as a cue to paternity; support for resemblance as a cue to paternity is limited by comparison. No evidence is found to support a role for MPA in paternity assessment. Findings regarding self-reported relatedness certainty as a possible mediator of the effects of paternity cues are mixed