Kin Recognition and Human Facial Resemblance

1. Kin Recognition and Human Facial Resemblance

2. Inclusive Fitness (favour kin) Why Recognize Kin? Mate Choice (avoid inbreeding)

3. Inclusive Fitness Theory • Relatives other than your direct offspring can share your genes. • Helping them to reproduce can increase your own fitness. • If organisms do show differential treatment to kin according to the degree of relatedness, how do they detect kinship?

4. Creating Resemblance Base Intermediate Template Morph Participant

5. self morph non-self non-self morph morph self morph Morphs Participants

6. Are people more likely to trust others with faces that resemble their own?

7. The Trust Game P2 DeBruine (2004) Proc Roy Soc Lond B

8. Effect of Resemblance on Game Behaviour Average Number (out of 3) DeBruine (2002) Proc Roy Soc Lond B

9. Transforming Faces Average Female Participant

10. Transforms Endpoint Faces ( ) Base Face Average Male Transform Subject = - X

11. Other-Sex Transform Same-Sex Transform Transformed Stimuli Subject

12. Do people find faces similar to their own more attractive?Is this different for same-sex and other-sex faces?

13. Click on the face you find more attractive.

14. Resemblance Increases “Attractiveness” Attractiveness Difference Score DeBruine (2004) Proc Roy Soc Lond B

15. Resemblance Increases “Averageness” Averageness Difference Score DeBruine (2004) Proc Roy Soc Lond B

16. Context-Specificity • Cues of kinship should cause context-specific effects that... • increase prosocial behaviour and attributions • decrease attractiveness for mating • Within the domain of mating, cues of kinship should be more aversive in the context of a short-term relationship than a long-term relationship. DeBruine (2005) Proc Roy Soc Lond B

17. Context-Specific Effects Average Difference Score

18. What causes individual differences in preferences for self-resemblance?

19. Menstrual Cycle Effects Average Self-Preference Score DeBruine, Jones & Perrett (2005) Hormones & Behavior

20. Self-resemblance preference Estrone glucuronide (mmol/L/24h) Pregnanediol glucuronide (umol/L/24h) Fertility risk Hormonal Correlates Fertility risk Estimated Estrogen Estimated Progesterone Day of menstrual cycle (n=71) DeBruine, Jones & Perrett (2005) Hormones & Behavior

21. Are there sex differences in how much people prefr self-resemblance in children’s faces?

22. Which of these children would you be most likely to adopt?

23. Platek vs. DeBruine Morphing Methods Changed Child Morph Original DeBruine (2004) Evolution & Human Behavior

24. Platek vs. DeBruine Results • Platek found that men preferred self-resemblance more than women, who still significantly preferred self-resemblance • DeBruine found that men and women preferred self-resemblance equally (Others could match the child faces made using both DeBruine and Platek methods equally well to the adult faces they were made from, and slightly more accurately for female adult faces than male adult faces)

25. Increases trustworthiness (both behaviours and attributions) Increases the attractiveness of same-sex faces more than other-sex faces Has different effects in mating and prosocial contexts Is affected by hormones across the menstrual cycle May or may not be evaluated differently by by men and women in the context of children’s faces Facial Self-Resemblance