Comparative PsychologyComparative Psychology

Evolution Evolution What is evolution & why are psychologists What is evolution & why are psychologists

interested?interested?

Reproductive behaviourReproductive behaviour How do men and women attract/choose How do men and women attract/choose

sexual partners?sexual partners? How has evolution shaped sexual behaviour How has evolution shaped sexual behaviour

(e.g. jealousy, infidelity)?(e.g. jealousy, infidelity)? Has evolution affected how men & women Has evolution affected how men & women

approach child-rearing?approach child-rearing?

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EvolutionEvolution

Charles Darwin’s attempt to explain the Charles Darwin’s attempt to explain the huge variety of living things…huge variety of living things………in a in a scientificscientific way way

……without drawing upon without drawing upon religiousreligious ideas ideas

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EvolutionEvolution

Each living thing (organism) has a set of Each living thing (organism) has a set of characteristics encoded by its genescharacteristics encoded by its genes

The organism inherits its genes from its The organism inherits its genes from its parent(s)parent(s)

Variations between organisms are caused Variations between organisms are caused by variations in the by variations in the genotypegenotype

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Environment

Environment contains a range of opportunities and threats (e.g. food

sources, predators)

EvolutionEvolution

Organism

Organism has particular

characteristics determined by its

genes

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EvolutionEvolution

An organism’s ability to survive depends An organism’s ability to survive depends on how well its characteristics allow it to:on how well its characteristics allow it to: Exploit the opportunities available in its Exploit the opportunities available in its

environmentenvironment Avoid or deal with the threats presented by its Avoid or deal with the threats presented by its

environmentenvironment

We call this the organism’s We call this the organism’s fitnessfitness

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FitnessFitness

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FitnessFitness

Yummy!

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EvolutionEvolution

Fit organisms are more likely to survive Fit organisms are more likely to survive into adulthood than unfit ones.into adulthood than unfit ones. Consequently, they are more likely to mate Consequently, they are more likely to mate

and have offspringand have offspring They pass on their genes to the next They pass on their genes to the next

generationgeneration

Gradually, the genes for successful Gradually, the genes for successful characteristics spread through the characteristics spread through the populationpopulation

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EvolutionEvolution

Fitness is all about how well an organism Fitness is all about how well an organism is adapted to its environmentis adapted to its environment The environment changes over time – The environment changes over time –

sometimes gradually, sometimes rapidlysometimes gradually, sometimes rapidly So a characteristic/gene that is So a characteristic/gene that is adaptiveadaptive at at

one time may become one time may become maladaptivemaladaptive if the if the environment changesenvironment changes

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FitnessFitness

Arse.Arse.Arse.

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EvolutionEvolution

Genotypes change due to:Genotypes change due to: Random mutation of DNARandom mutation of DNA Recombination of genes due to matingRecombination of genes due to mating

New species emerge as adaptive changes New species emerge as adaptive changes spread through a populationspread through a population Species compete with each other – the fittest Species compete with each other – the fittest

‘wins’ by reproducing more effectively‘wins’ by reproducing more effectively Species go extinct when their environment Species go extinct when their environment

disappears or they are out-competeddisappears or they are out-competed

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Evolution MythsEvolution Myths

Characteristics acquired during the Characteristics acquired during the lifespan can be passed on to offspring lifespan can be passed on to offspring

Humans are descended from monkeysHumans are descended from monkeys

Other animals are ‘less evolved’ than usOther animals are ‘less evolved’ than us

Humans are the ‘end product’ of evolutionHumans are the ‘end product’ of evolution

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Evolution & PsychologyEvolution & Psychology

Evolutionary psychology regards humans Evolutionary psychology regards humans as subject to same evolutionary processes as subject to same evolutionary processes as other animals (continuity)as other animals (continuity) Assumes that behavioural characteristics can Assumes that behavioural characteristics can

be inherited just like physical onesbe inherited just like physical ones Tries to explain human behaviour/psychology Tries to explain human behaviour/psychology

in terms of evolutionary processesin terms of evolutionary processes

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Evolution & PsychologyEvolution & 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

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