Sociosexuality

1
Sociosexuality

• MSc EP module 2006/07
• EP Session 4

2
What is sociosexuality ?

• Simpson Gangestad, 1991, JPSP 60, 870-883
  1992, J. Personality, 60, 31-51
• 7 Questionnaire items
• With how many different partners have you had sex
  (sexual intercourse) during the past year
• How many different partners do you foresee
  yourself having sex with during the next five
  years
• With how many partners have you had sex on one
  and only one occasion
• How often do you fantasize about having sex with
  someone other than your current dating partner
• (options 1 never, 2 once every 2-3 months, 3
  once a month, 4 once every 2 weeks,
• 5 once a week, 6 a few times each week, 7
  nearly every day) /continued

3
Sociosexuality (cont)

• Plus three questions about attitude to engaging
  in casual, uncommitted sex
• Sex without love is OK
• I can imagine myself being comfortable and
  enjoying casual sex with different partners
• (REVERSE KEYED) I would have to be closely
  attached to someone (both emotionally and
  psychologically) before I could feel comfortable
  and fully enjoy having sex with him or her
• Response scales 1 strongly disagree, to 7
  strongly agree

4
Individual differences in sociosexuality

• Low score implies restricted sociosexual
  orientation prolonged courtship, monogamy,
  substantial emotional investment in relationships
• High score implies unrestricted sociosexual
  orientation quick to have sex, tend towards
  promiscuity, romantic relationships may not
  involve great closeness
• Men are typically nearer than women to the
  unrestricted end of the scale cf Clark
  Hatfields study in which men or women were
  approached with an invitation to go out with me
  tonight/ come to my apartment tonight/ sleep with
  me tonight by an attractive accomplice.
• Confirmed by Schmitt, 2005, BBS 28, 247-311
  across 48 nations
• SOI score reflects relative importance of
  short-term benefits from sex vs. long-term
  investment in the family

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Differences between nations

• From Schmitt, 2005, BBS 28, 247-311
• Nations mean SOI score is related to the sex
  ratio of nation
• r -0.45
• On left of panel, mens evolved desires dominate
  on the right, womens desires drive the behaviour

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How does SOI relate to the Big 5

• Schmitt Buss, 2000, J. Res. Personal. 34,
  141-177
• Standard personality work misses dimensions
  relevant to evolutionary theory because its
  exclusion criteria eliminate adjectives showing
  sex linkage, and some others as peripheral
  terms
• Found 7 factors in list of adjectives related to
  sexual aspects of personality

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7 factors and example adjectives

• Sexual attractiveness - alluring
• Relationship exclusivity faithful, r(SOI) 0.61
• Gender orientation feminine, manly
• Sexual restraint - chaste
• Erotophilic disposition - shameless
• Emotional investment - loving
• Sexual orientation homo- / bi-sexual,

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Relations (1) r(male), r(female)

• II Relationship exclusivity
• Extraversion -0.21, -0.11
• Agreeableness 0.20, 0.37
• Conscientiousness 0.11, 0.23
• IV Sexual restraint
• Extraversion -0.39, -0.33
• V Emotional investment
• Extraversion 0.26, 0.24
• Agreeableness -0.21, 0.50

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Relations (2) r(male), r(female)

• Erotophilic disposition
• Extraversion 0.26, 0.43
• Agreeableness -0.30 , -0.21
• Conscientiousness -.16, -0.26

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Relations (3) r(male), r(female)

• I Sexual attractiveness
• Extraversion 0.45, 0.41
• III Gender orientation
• Agreeableness -0.07, 0.25
• VII Sexual orientation
• Openness 0.23, 0.24

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Sociosexuality and early childhood

• Suggestion (by Chisholm, Belsky, etc.) that
  developing females assess their fathers PI
  (father absent/present) and use it to predict the
  child-rearing support that will be available when
  they are adult
• If father present, they look for reproductive
  partners who will provide resources for their
  shared offspring
• If father absent, they switch to life-history
  path with early sexual maturity plus an
  opportunistic / mistrustful relationship style,
  and use their sexuality to get men to offer
  resources
• So these F-Abs females would develop an
  unrestricted sociosexual orientation
• Relevant data in Quinlan (see earlier SB lecture)

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Maestripieri et al (2004)

• Developmental Science 7 (5), 560-566
• Greater interest in infant stimuli in female
  adolescents whose father was absent in early
  childhood
• F-Abs also linked to earlier menarche (but
  separately)

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Father absence and face shape

• Boothroyd Perrett (2006) PRSB 273, 1355-1360
• Facial composites of women father absent vs.
  both parents, poor relationship vs. both parents,
  good relationship
• Differences in attractiveness, health, and
  masculinity in the composite faces WHR, BMI,
  etc. also differed in correlation with early
  father presence and parents relationship

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Differences in female preferences linked to SOI

• Waynforth et al. (2005) EHB, 26, 409-416
• Pairs of (male) faces of varying masculinity
  (after PCA of several indices)
• Overall, female raters preferred the more
  feminine of paired male faces
• Higher SOI in female judges was associated with a
  greater preference for the face that was more
  masculine (as indicated by the chin depth and
  face width)
• Considered that women seeking a short-term
  relationship would maximise their payoff by
  seeking more-masculine features (good genes)
  those seeking long-term parental care would
  trade-off gene quality against the greater
  paternal investment from less-masculine men

15
SOI and genetics

• The Chisholm/Belsky hypothesis implies that
  female early menarche and SOI score reflect
  circumstances in early (shared) family
  environment
• But could be that good-gene fathers are likely to
  desert (giving a F-Abs family), AND pass on genes
  which make female children BOTH early-maturing
  and unrestricted sociosexually

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Baileys Australian twin data

• Bailey et al., 2000, JPSP 78, 537-545
• 4901 twins zygosity, SOI (augmented with items
  from Eysenck), sexual history, parental marital
  status
• SOI predicted by own marital status (35), age
  (3), and parental marital status (1 variance)
• Genetic models HERITABILITY
• Additive genetic 0.49 (M 0.26, F 0.43)
• Shared environment 0.02 (M 0.24, F 0.09) low in
  F
• Non-shared envir. 0.47 (M 0.49, F 0.46)
• So shared family environment in females is much
  less important than shared genes

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Correlates of unrestricted sociosexuality

• Mikach Bailey 1999 EHB 20, 141-150
• Compare women with unusually high number of sex
  partners with women with few sex partners
• Lower WHR but not otherwise more attractive
• Higher interest in casual sex
• Higher importance of partners attractiveness
• NO difference in sexual vs emotional jealousy
• Higher interviewer-rated masculinity (physical
  and behavioural), childhood gender nonconformity,
  continuous gender identity

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Reading

• Schmitt (2005) BBS 28(2), 247ff - peer reviewed
  study of SOI across 48 nations
• Schmitt Buss (2000) J. Res. Personality, 34,
  141-177
• Quinlan (2003) Evol. Hum. Behav., 24, 376-390
• Chisholm (1993) Curr. Anthrop. 34(1), 1-24 also
  peer reviewed