PS4029/30 Perspectives on social attributions Lecture 7 March 2005

Lecture 7: Sexual dimorphism & attractiveness attractive faces deviate from average [recap] 2. sex. dim. and non-human mate choice 3. attitudes to masculinity in human faces 4. Systematic variation in female preferences for sexual dimorphism in male faces 5. Strategic female preferences for masculine males (intro)

1. Evidence against averageness accounts of attraction [recap] Perrett et al (1994) showed that very attractive faces are not average Most attractive of 3 faces A B Average of 60 Average of Most attractive Hyper-attractive Exaggerate differences between A + B

2. Sex dim and non-human mate choice (Andersson,1994) IN MOST SPECIES FEMALES CHOOSE MATES WITH EXAGGERATED MASCULINE TRAITS - - WHY??

MASCULINE MALES & GOOD GENES FOR IMMUNOCOMPETENCE masculine traits caused by testosterone testosterone is an immunosuppressant to develop masculine traits you need to have a strong immune system masculine traits signal heritable immune system strength (but not necessarily current condition)

NON-HUMAN MALES PREFER FEMININE FEMALES thought to choose feminine females as mates because such females are fertile This increases the males chances of increasing their reproductive success

3. ATTITUDES TO MASCULINITY IN HUMAN F ACES DO HUMAN MALES PREFER FEMININE FEMALE FACES? DO HUMAN FEMALES PREFER MASCULINE MALE FACES? THIS IS A VERY STRONG PREDICTION FROM ANIMAL LITERATURE

3. ATTIUDES TO MASCULINITY IN HUMAN FACES surprising aversion to masculinity in both male + female faces feminine warm honest good parent “dad” masculine cold dishonest bad parent “cad” feminine masculine Perrett et al. Nature (1998)

4. SYSTEMATIC VARIATION IN FEMALE PREFERENCES FOR MASCULINE MALES Although women seem to generally prefer feminine male faces, the strength of this preference seemed highly variable in the Perrett et al 1998 study Is this variation in female preferences for sexual dimorphism in male faces random or systematic?

MASCULINITY OF ODOUR PEOPLE GENERALLY DON’T LIKE MASCULINE FACES WHAT ABOUT ODOURS? MALE PHEREMONE (A CHEMICAL SIGNAL OF ‘MALE’)

FEMALE ATTRACTION TO MASCULINITY IN MALE FACES AND ODOURS 20 15 r60=0.40, p=0.002 10 Preferred face masculinity (%) 5 neutral like -5 20% 17% dislike 64% -10 Pleasantness of male sex pheromone Cornwell et al. Proc Roy Soc (2004)

Masculinity preferences and ‘perceptual bias’ Preferences for faces that deviate from average are hard for perceptual bias accounts to explain Systematic variation in preferences is also hard for perceptual bias accounts to explain

5. Strategic female preferences for masculine males (intro) There are possible benefits (e.g. healthy offspring) to choosing a masculine male for a short-term relationship (where investment NOT important) There are possible costs to choosing a masculine male as a long-term partner (e.g. low investment - Mazuur and Booth 1998, Perrett et al 1998) Are individual differences in women’s masculinity preferences ‘strategic’?

Key themes People prefer feminised male and female faces to average or masculinised versions It is surprising women do not prefer masculine male faces as facial masculinity may signal ‘good genes’ for immunocompetence Women’s preferences for masculinity seem to be systematic (some women more tolerant of masculinity than others are), suggesting there may be a strategy at work

Menstrual cycle, ‘pill’, pregnancy and illness avoidance Next week Strategic female preferences for masculine faces as evident in change in face preferences across the menstrual cycle Menstrual cycle, ‘pill’, pregnancy and illness avoidance