Comparative Psychology Evolution What is evolution & why are psychologists interested? What is evolution & why are psychologists interested? Reproductive behaviour How do men and women attract/choose sexual partners? How do men and women attract/choose sexual partners? How has evolution shaped sexual behaviour (e.g. jealousy, infidelity)? How has evolution shaped sexual behaviour (e.g. jealousy, infidelity)? Has evolution affected how men & women approach child-rearing? Has evolution affected how men & women approach child-rearing?

Evolution Charles Darwin’s attempt to explain the huge variety of living things… …in a scientific way …without drawing upon religious ideas

Evolution Each living thing (organism) has a set of characteristics encoded by its genes The organism inherits its genes from its parent(s) Variations between organisms are caused by variations in the genotype

Environment Environment contains a range of opportunities and threats (e.g. food sources, predators) Evolution Organism Organism has particular characteristics determined by its genes

Evolution An organism’s ability to survive depends on how well its characteristics allow it to: Exploit the opportunities available in its environment Exploit the opportunities available in its environment Avoid or deal with the threats presented by its environment Avoid or deal with the threats presented by its environment We call this the organism’s fitness

Fitness

Fitness Yummy!

Evolution Fit organisms are more likely to survive into adulthood than unfit ones. Consequently, they are more likely to mate and have offspring Consequently, they are more likely to mate and have offspring They pass on their genes to the next generation They pass on their genes to the next generation Gradually, the genes for successful characteristics spread through the population

Evolution Fitness is all about how well an organism is adapted to its environment The environment changes over time – sometimes gradually, sometimes rapidly The environment changes over time – sometimes gradually, sometimes rapidly So a characteristic/gene that is adaptive at one time may become maladaptive if the environment changes So a characteristic/gene that is adaptive at one time may become maladaptive if the environment changes

Fitness Arse.

Evolution Genotypes change due to: Random mutation of DNA Random mutation of DNA Recombination of genes due to mating Recombination of genes due to mating New species emerge as adaptive changes spread through a population Species compete with each other – the fittest ‘wins’ by reproducing more effectively Species compete with each other – the fittest ‘wins’ by reproducing more effectively Species go extinct when their environment disappears or they are out-competed Species go extinct when their environment disappears or they are out-competed

Evolution Myths Characteristics acquired during the lifespan can be passed on to offspring Humans are descended from monkeys Other animals are ‘less evolved’ than us Humans are the ‘end product’ of evolution

Evolution & Psychology Evolutionary psychology regards humans as subject to same evolutionary processes as other animals (continuity) Assumes that behavioural characteristics can be inherited just like physical ones Assumes that behavioural characteristics can be inherited just like physical ones Tries to explain human behaviour/psychology in terms of evolutionary processes Tries to explain human behaviour/psychology in terms of evolutionary processes

Evolution & Psychology Slow Physically weak Lacking agility Poor climber Small teeth No claws Highly dependent young Poor night vision Large brain Planning Imagination Language Social organisation Tool use Communication Problem solving