Data from: Kin recognition: evidence that humans can perceive both positive and negative relatedness

The evolution of spite entails actors imposing costs on ‘negative’ relatives: those who are less likely than chance to share the actor’s alleles and therefore more likely to bear rival alleles. Yet, despite a considerable body of research confirming that organisms can recognise positive relatives, little research has shown that organisms can recognise negative relatives. Here, we extend previous work on human phenotype matching by introducing a cue to negative relatedness: negative self-resembling faces, which differ from an average face in the opposite direction to the way an individual’s own face differs from the average. Participants made trustworthiness and attractiveness judgements of pairs of opposite-sex positive and negative self-resembling faces. Analyses revealed opposing effects of positive and negative self-resembling faces on trustworthiness and attractiveness judgements. This is the first clear evidence that humans are sensitive to negative relatedness cues, and suggests potential for the adaptive allocation of spiteful behaviour.

Dryad Dataset
Behavioural results for positive and negative self-resemblance experiment. Codes are as follows: id = participant number; yoke_id = number of the participant who also evaluated the focal participant's stimuli (yoked participant); sex = participant sex; ts_self = focal participant's trust preference score for focal participant's positively resembling images; ts_yoke = yoked participant's trust preference score for focal participant's positively resembling images; ls_self = focal participant's long-term attractiveness preference score for focal participant's positively resembling images; ls_yoke = yoked participant's long-term attractiveness preference score for focal participant's positively resembling images; ss_self = focal participant's short-term attractiveness preference score for focal participant's positively resembling images; ss_yoke = yoked participant's short-term attractiveness preference score for focal participant's positively resembling images; ta_self = focal participant's trust preference score for focal participant's negatively resembling images; ta_yoke = yoked participant's trust preference score for focal participant's negatively resembling images; la_self = focal participant's long-term attractiveness preference score for focal participant's negatively resembling images; la_yoke = yoked participant's long-term attractiveness preference score for focal participant's negatively resembling images; sa_self = focal participant's short-term attractiveness preference score for focal participant's negatively resembling images; sa_yoke = yoked participant's short-term attractiveness preference score for focal participant's negatively resembling images.

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