PSYCH109 - EVOLUTIONARY 35 KEY POINTS

What is evolutionary psychology?

The study of how evolution by natural selection has shaped psychological mechanisms and behaviour.

What did Dobzhansky mean by “nothing in biology makes sense except in the light of evolution”?

Biological traits and behaviours are best understood by considering their evolutionary history and function.

What is comparative psychology?

The study of behaviour and cognition across different animal species, often to understand similarities, differences, and the evolutionary origins of psychological abilities.

What is a homology?

A similarity between traits because they were inherited from a common ancestor, even if they now serve different functions.

What is an analogy?

A similarity between traits that evolved independently because they perform similar functions, rather than because of common ancestry.

What three conditions are necessary for natural selection to occur?

There must be variation between individuals, some variation must be heritable, and individuals must differ in reproductive success.

What is a gene?

A segment of DNA that contributes to the development or functioning of an organism and can be passed between generations.

What is a genotype?

An individual's genetic makeup.

What is a phenotype?

The observable characteristics of an individual, produced by interactions between genes and the environment.

What is the nature–nurture interaction?

Behaviour and psychological characteristics are influenced by both genetic and environmental factors, which can interact with one another.

What does heritability measure?

The proportion of variation in a particular trait within a particular population that can statistically be attributed to genetic differences.

What does heritability NOT tell us?

It does not tell us how genetic a trait is in an individual, nor does high heritability mean that a trait cannot be changed by the environment.

Why are identical (MZ) and fraternal (DZ) twins useful in behavioural genetics?

MZ twins share nearly all their genetic variation, whereas DZ twins share roughly half on average. Comparing their similarity can provide evidence about genetic and environmental contributions.

What is the Flynn effect?

The observed increase in average IQ scores across generations, demonstrating that cognitive performance can change substantially with environmental and societal conditions.

What does the MAOA example illustrate about genes and behaviour?

Genetic influences on behaviour can depend on the environment, illustrating that genes do not simply determine behaviour independently of experience.

What does it mean to say that behaviour is malleable?

Behaviour can change in response to environmental conditions, learning, development, and experience, even when genetic factors contribute to it.

What is WEIRD research?

Research based on populations that are Western, Educated, Industrialised, Rich, and Democratic.

Why is relying heavily on WEIRD participants a problem?

WEIRD populations represent a relatively small and unusual portion of humanity, so findings from them may not generalise to all human populations.

What did Henrich, Heine, and Norenzayan (2010) argue about psychology research?

They highlighted that many psychological studies rely heavily on WEIRD populations, despite these populations representing only a small fraction of the world's population.

What is conformity?

Changing one's behaviour or beliefs to match those of other people, often because social information influences what appears appropriate or correct.

What is prestige bias?

A tendency to preferentially learn from or copy individuals who are perceived as successful, prestigious, or high-status.

What is over-imitation?

Copying even unnecessary or causally irrelevant actions performed by another individual when learning how to achieve a goal.

What does the Müller-Lyer illusion demonstrate about culture?

Perception can be influenced by cultural and environmental experience, showing that some aspects of perception are not completely universal.

Why is culture important from an evolutionary perspective?

Humans have evolved psychological mechanisms that allow us to learn from and adapt to other people, allowing behaviours and information to spread culturally.

What is the basic idea behind the “selfish human nature” view?

Humans may be motivated to pursue their own survival and reproductive interests, potentially producing competition and conflict with others.

What do dictator and ultimatum games demonstrate about human cooperation?

People often show fairness, generosity, and concern for others, even when they could keep more resources for themselves, suggesting human behaviour cannot be explained solely by immediate self-interest.

How do chimpanzees and bonobos differ in their social behaviour?

Chimpanzees tend to show more aggression and competitive behaviour, whereas bonobos tend to show more affiliative and conflict-reducing behaviour, illustrating variation in social strategies among closely related species.

What did the Lord of the Flies example raise about human nature?

It raises the question of whether humans naturally become competitive and aggressive when social constraints are removed, although real human behaviour is more complex than the fictional example suggests.

What is catharsis?

The idea that expressing or releasing aggression reduces later aggression. Psychological research has generally challenged the idea that acting aggressively simply “gets aggression out.”

What is a phylogenetic constraint?

A limitation on evolutionary change caused by an organism's existing biological structure and evolutionary history.

What is an evolutionary trade-off?

A situation where improving one trait or function comes at a cost to another, because organisms have limited resources.

What is adaptive lag?

The delay between a change in the environment and evolutionary adaptation to that change, meaning mechanisms that were useful in ancestral environments may not work optimally today.

What is an evolutionary mismatch?

A situation where a psychological or behavioural adaptation that was useful in an ancestral environment produces less adaptive outcomes in the modern environment.

How can evolutionary mismatch help explain modern obesity?

Mechanisms that evolved to encourage humans to seek and consume energy-rich foods could become maladaptive in environments where high-calorie food is constantly available.

How can evolutionary psychology explain modern problems such as social media or decision-making biases?

Psychological mechanisms evolved under ancestral conditions, so modern environments can exploit or trigger these mechanisms in ways they were not originally designed for, producing behaviours such as attention capture, social comparison, or predictable decision-making biases.