Evolution, Natural Selection, and Aggression Flashcards
Define Evolution
The changes in inherited characteristics in a biological population over successive generations.
Define Natural Selection
Inherited traits that enhance an animal’s reproductive success are passed on to the next generation an.d thus ‘selected’. Animals without these traits are not selected.
Define Sexual Selection
Attributes or behaviours that increase reproductive success are passed on and may become exaggerated over succeeding generations of offspring
Who proposed the idea of natural selection?
Charles Darwin.
Sexual Selection - Behavioural Characteristics
Provide an advantage over competitors for reproductive rights. A male being aggressive allows him to fend off potential reproductive rivals. These characteristics are passed off to offspring if genetically determined and remain in the population.
Evolution and Aggression
In human evolution, being able to protect yourself and possessions would have enhanced survival reproduction, so you would have been modified by natural selection.
Guarding your partner - Margo Wilson and Martin Daly
Mate retention strategies are used to guard partner and prevent them from straying.
Direct guarding involves male vigilance over a partners behaviour, like checking who they’ve been seeing, where they are etc.
Guarding your offspring
Human parents will direct aggressive acts against people/animals that threaten their children.
This aggression is adaptive as each child is a valuable genetic commodity. Aggression protects their ‘investment’.
Guarding your offspring - Steiner
Steiner points out that protecting offspring is one of the few situations where females are just as aggressive as males.
Strength of Evolution Theory
Can explain why males are more aggressive than females.
Females that are cooperative are likely to be naturally selected because cooperation helps protect them and their offsprings.
Reduced aggression is selected in females whereas males who are aggressive are more likely to be selected because they make better hunters.
Evidence from chimpanzees supports this (Manson and Wrangham). It explains gender differences in aggression today, increasing the theory’s validity.
Competing the Gender Differences
The EE is uncertain as it’s impossible to test evolution directly, this is why most research is correlational.
As a result this method cannot draw cause effect conclusions. Variables are measured and not manipulated, correlational research can never rule out the effects of other factors on aggression.
Weakness - Cultural Differences
Difference in cultures between aggressive behaviour.
In the !Kung San people of the Kalahari, aggression is discouraged from childhood so it is rare.
Contrasting this is the Yanomami of Venezuela and Brazil who are described as fierce - aggression is an accepted behaviour to gain status.
Differences are not universal and suggest that innately determined behaviour can be outweighed by cultural norms.
Application - Reproductive Behaviour
ET can help understand human relationships as it predicts we should choose partners who will enhance our reproductive success.
Buss 1989 found across 33 countries, males preferred younger, more attractive and chaste women, likely for more reproductive success.
Females preferred older, successful, hard-working men, as it enhances their reproductive success of supporting their children.
Supports the theory as it shows the predictions from the theory are upheld by evidence.
