Evolutionary Explanations for Partner Preferences

Evolutionary Explanations for Partner Preferences

1. Sexual Selection

   • Behaviours and physical adaptions in order to achieve mating success
     • Males
       • Prominent cheekbones, square jaw
         • Advertises good genes
         • Created by testosterone
       • Look for females that aren't too promiscuous, have symmetrical faces and an hourglass figure - 0.7 hip-to-waist ratio
         • This advertises fertility and also that they're not already pregnant
     • Females
       • Look for males that are muscular indicating strength and good genes
         • Meaning they can collect resources
       • Look for a hip to waist ratio of 0.9 in males
         • More fat means they may not live much longer or they're unfit

2. Differences in reproductive behaviour

   • Anisogamy
     • Difference in nature and number of gametes
       • Males
         • Produce 100 million sperm per ejaculation
           • Cheap to produce and plentiful
           • This maximises reproductive success - they will try to mate with as many females as possible and produce many offspring
         • Fertile from adolescence until death
       • Females
         • Produce 1 egg per month
           • Only fertile for a few days a month
           • Rare and expensive to produce
           • More selective over partners and invest heavily in one pregnancy and offspring at a time
         • Fertile from adolescence until around 40

3. Sexual Dimorphism

   • Differences in size and behaviour between males and females of a species
     • Males larger but not that much

4. Polygamy vs Monogamy

   • Monogamy
     • One partner at a time
       • Serial monogamy
     • Females
       • Inter-sexual selection
         • Quality over quantity
   • Polygamy
     • More than one partner at a time
       • Males
         • Intra-sexual selection
           • Compete with other males for access to fertile females

5. Physical attractiveness

   • Is important because it tells the opposite sex that you have good genetic potential
     • In males it demonstrates ability to collect resources to maintain appearance

6. Hip to Waist ratio

   • Males find a ratio of 0.7 most attractive in females
     • Displays that...
       • They're not already pregnant
       • They're old enough to reproduce
       • They're not going through the menopause
   • Females prefer a ratio of 0.9 in men
     • It indicates genetic fitness

7. Facial and body Symmetry

   • Seen as an attractive and desirable trait because it requires genetic precison

8. Evaluation

   • Methods used in research often involve self-report
     • Self reports can give socially desirable answers and make findings invalid
   • Appears to have predictive validity
     • Allows us to predict behaviour eg males will prefer females that show signs of fertility
   • Generally, although it displays predictive validity, the theory cannot be falsified
     • Not scientific - explanations are ad hoc - explained after it has happened
       • So they always sound plausible