evolution, aggression

• Evolution (Darwin)

  Genetic diffs between organisms - those with genes suited to environment survive and pass them to offspring - natural selection
• Sexual selection

  Characteristics that may seem disadvantageous (eg peacock tail - visible to predators) may be attractive to potential mates as it shows fitness - surviving despite burden - increases chances of reproductive success

  Other characteristics (especially behavioural) are adapted to give advantage over competitors for reproductive rights eg. male aggression
• Inter and intrasexual selection

  inter - members of one sex choose members of another sex eg females have a preference over men who are strong and males prefer young (more fertile women)

  intra - members of same sex compete for access to members of opp sex
• Aggression

  Males often aggressive when guarding their partner t prevent them 'straying' and females more surveillant

  When guarding offspring, females and males equally aggressive - Steiner. protecting their 'investment' to increase chances of its reproductive success - 'valuable genetic commodity'
• Application to reproductive behaviour

  Helps understand human relationships. Buss found that across 33 countries males preferred younger more attractive and chaste women - more likely fertile and females preferred older wealthier and ambitious men to support children

  shows how predictions from theory are upheld by evidence
• Can't explain cultural diffs

  Kung San people from Kalahari (desert) are discouraged from aggression since childhood and so it's rare that they are

  Yanomami people of Venezuela and Brazil are described as 'fierce people' where aggression is accepted to gain status

  suggest innately determined behaviour can be outweighed by cultural norms
• Strength 2

  Shackleton et al surveyed 461 men and 560 women in committed relationships. They found positive correlation between men who used mate retention techniques (eg direct guarding) and use of violence. Men also tended to use emotional manipulation as a technique - non-physical aggression
• Weakness 2

  Buss and Shackleton argue we can't directly observe how aggression evolved in ancestral environments, meaning evolutionary theories often rely on speculation rather than direct scientific testing - unfalsifiable