Evolutionary Explanations for Partner Preferences

• Human reproductive behaviour describes evolved processes that explain our preferences in a partner to reproduce
• Natural Selection:

  Through sexual dimorphism different characteristics evolve in men and females. Secondary sexual characteristics are displayed to be selected by a mate. Males display ability to protect + provide and females display fertility
• Sexual Selection - display of desirable characteristics to increase an individual's chance of securing a mate for sexual reproduction
• Inter Sexual Selection - selecting an ideal mate with certain desirable qualities to mate and pass on genes. Women are more likely to engage in this as they choose quality over quantity and have limited reproductive possibilities.
• Intra Sexual Selection - members of the same sex compete to gain access to members of the opposite sex. Men normally engage in this to show their ability to protect and provide. Men have numerous reproductive possibilities.
• women are biologically motivated to invest more in caring for their offspring and are motivated to carefully select an idea mate to pass on their selfish genes. Women seek signs of provision (wealth, social status) and less signs of protection (muscular)
• Men are biologically motivated to invest less in caring for their offspring and motivated to compete to be selected by numerous fertile mates. Men seek signs of youth (rosy cheeks, lips)
• Theories to explain evolutionary advantage of human reproductive behaviour:

  1. Biological Market Place Theory - Noe & Hammerstein 1995
  2. Sexual Strategies Theory - Buss & Schmitt 1993
• Evolutionary advantage of mating behaviours:

  1. long Term Courtship
  2. Mate Guarding
  3. One Night Stands and Sneak Copulation
• Long Term Courtship - long term relationships are advantageous to men as they enable them to retain access to one fertile woman. For females a long term relationship means the increased investment of resources by her men for her and her children, reducing the chance he may abandon her
• Mate Guarding - couples monitor each other to ensure other potential partners know they are taken. Men do not want to waste their resources on a child that does not share his selfish gene. Women need to ensure their male uses all his resources on her
• One Night Stands:

  Advantageous to men as they increase their reproductive possibilities without heavy investment. Provides women access to a wider gene pool to maximise the chance of their offspring reaching sexual maturity and pass on her selfish gene. Could also allow her to remain in a long term relationship (resource rich) with an offspring (genetically fit)
• Sneak Copulation - offspring will have one offspring gene but another man will use his resources to raise the child
• Sex Sons Hypothesis (Fisher 1930) - females select desirable males as they know their sons will also have desirable traits
• Runaway Process can occur when certain characteristics become fashionable over time
• Handicap Hypothesis (Zahavi 1975) - females select males with some disadvantage to show his ability to thrive as this is a sign of his superior genes
• Sexual Selection & Human Reproductive Behaviour Evaluation:

  (P) convincing evidence for the role of sexual selection in partner preferences

  (E) Buss (1989)

  (E) cross cultural study of 10,000 participants across 33 countries found that men sought physically attractive and younger women whilst women looked for a male's financial capacity

  (L) due to a woman's limited reproductive opportunities they choose a partner that can best provide, whilst men due to their numerous reproductive opportunities, choose a partner whose youth and fertility lead to best reproduction
• Sexual Selection evaluation:

  (P) supporting research evidence for the role of sexual selection in partner selection

  (E) Gross & Singh

  (E) found that male shoulders to waist ratio of 0.85 - 0.9 is most attractive and a females hip to waist ratio of 0.7 is most attractive

  (L) these ratios are universal and shows that men look for child bearing abilities and women look for protection
• Human Reproductive Behaviour Evaluation:

  (P) Evidence for the role of sexual selection in human reproductive behaviour

  (E) Clarke + Hatfield (1989)

  (E) used confederates to offer casual sex to men and women. 75% of male participants agreed, no women did

  (L) suggesting men compete to be selected by numerous female partners and are more likely to agree to an opportunity to reproduce whereas women are less likely to agree as they have limited reproductive opportunities
• Sexual Selection & Human Reproductive Behaviour Evaluation:

  (P) biologically determinist

  (E) theory suggests that out free choice is limited by internal biological factors

  (E) evolutionary explanations suggest human reproductive behaviour is limited by evolution, genetic characteristics that we have no control over

  (L) this limits our free will & ability to choose our partner or not to have children. evolutionary explanations does not explain homosexual relationships which are common in modern society