Evolutionary Psychology
H1. Introduction to evolutionary psychology
Principal assumption evolutionary psychology
● Human mind: organ designed by natural selection to guide individual in making decisions that
aid survival and reproduction
● Human mind: designed to learn, so evolutionary psychology doesn't suggest everything is innate
Fundamental assumptions evolutionary psychology
● Human mind: product of evolution
● Gain better understanding of mind by examining evolutionary pressures that shaped it
What can an understanding of evolution bring to psychology?
● Not all body parts are as easy to understand → peacock's tail: it’s huge, makes it difficult to
escape and requires energy to sustain it
Ultimate + proximate questions
● Ultimate: why particular behaviour exists at all
● Proximate: how a behaviour develops, whether it’s acquired or innate
Current Darwinian Theory
● Beneficiaries of behaviour are, in many cases, our genes
Richard Dawkins; replicator-vehicle distinction
● We’re survival machines, robot vehicles programmed to preserve selfish molecules known as
genes
● Only applies to evolved behaviour; any non-involved behaviour, like purely learned behaviour,
may not benefit genes at all
Aristotles; 384-322 BC
● Killed evolutionary thinking → proposed each species occupies a particular space in hierarchical
structure “great chain of being” or “scale nature”
● Hierarchie: god, angels, nobility, normal men, women, animals, plants, inanimate objects. Moving
up/down not permitted → natural order of things
Immanuel Kant; 1798
● Direct contradiction of aristotles; one organism can change over time, maybe acquire
characteristics of other organisms (not just physical changes)
Erasmus Darwin; 1731-1802 (Darwin’s grandfather)
● All living things could have emerged from common ancestor
● Competition might be driving force behind evolution
● Failed to produce plausible mechanism for evolutionary change
Jean-Baptiste Lamarck; 1744-1829
● 1st law: changes in environment can lead to changes in animals’ behaviour → might lead to
organ being used more or less
● 2nd law: such changes are heritable
Lamarck’s theory; Inheritance of acquired characteristics
● Incorrect; environment can affect organs, such changes can’t be passed onto offspring
● Charles Darwin still mentioned Lamarck as great influence in development of his theory of
evolution: natural selection
Natural selection depends on two components
● Heritable variation; people in population differ from each other in ways that are passed onto
offspring
,● Differential reproductive success; as result of these differences, some leave more surviving
offspring than others
● Can see this in asexcual species; individual reproduces by producing identical copy of itself
Variation for asexual species
● Only from copying errors (mutations)
Sexually reproducing species
● Combine genes of 2 individuals; offspring’s always different from either
Gregor Mendel; Breeding hybrid pea plants
● Greatest insight; inheritance is particulate
● (Darwin: traits of an individual are blended traits of father/mother) → Incorrect. Mendel:
○ Crossed white with red pea plant: offspring always red or white, never pink
● Why some traits do blend; traits controlled by single genes: inheritance is particulate
Materialism
● See mind as ultimately reducible to activity of the brain
Why materialism is important to evolutionary psychology
● If the mind is just brain activity, then the brain is subject to pressures of natural selection → mind
+ behaviour are product of evolution by natural selection
Francis Galton; 1822-1911 (Darwin’s cousin)
● Influenced by theory of natural selection
● Character + intelligence are inherited traits
● Developed some of 1st intelligence tests to explore this
● Anticipated method of experimental psychology by emphasising need to use data from large
samples of individuals
● Proposed traits useful in ancestral times, might be less useful now
Francis Galton’s way of improving society;
● Selective breeding
● Positive eugenics: individuals whose traits benefit society → encouraged to produce many
offspring
● Negative eugenics: those with traits less desirable → discouraged to produce offspring
William James; 1842-1910
● Made distinction between short- and long term memory
● Interest in consciousness
● Outlined instincts as fear, love, curiosity → driving forces human nature
● Human behaviour characterised by more instincts than other animals’
Concept of instincts was dropped in 20th century (William James)
● Because too imprecise to be scientifically meaningful
Tooby + Cosmides
● Called traditional non-evolutionary science approach: Standard Social Science Model SSSM
SSSM; assumptions about human behaviour
● Humans are born as blank slates (personality form cultural environment)
● Human behaviour is malleable (no biological constraints)
● Culture is autonomous (exists independently of people)
● Human behaviour determined by learning, socialisation, indoctrination
● Learning processes are general (can be applied to variety of phenomena)
Establishment SSSM
● Reaction to some extreme claims of biological determinists early 20th century
Non-westerners failing western-style intelligence tests
● On lower rung on evolutionary ladder
,● Eugenicists used results to recommend forced sterilisation etc.
● Misunderstandings of Darwin’s ideas
Humans did not descend from chimpanzees
● Both descended from common ancestor
● Chimps have their own particular adaptations that we don’t have
Franz Boas; Founder cultural relativism
● Many differences between people are due to differences in culture
● Want to understand people → must understand their culture
Biophobia
● Fear of biological explanations of human behaviour
Explanations biophobia
● Once scientific paradigm is established, it’s difficult for researchers to consider alternative
explanations that lie outside the paradigm (seen as old ways of thinking)
● Eugenic atrocities WWII made people fearful of censure
Evolutionary thinking in 4 disciplines
● Ethology
● Behavioural ecology
● Sociobiology
● Evolutionary psychology (Santa Barbara School)
Ethology
● Comes from Greek; character or habit
● Observation animal behaviour in natural setting
● Combine evolutionary/functional explanations with causal explanations
● 20th century: emphasised interactions genes-environment
● Lorenz, Tinbergen, Von Frisch
Behavioural Ecology
● Grew out of ecology. Differs: use economic cost-benefit models to predict how animals should
behave in given environment → models used to make predictions and compare against actual
animal behaviour
● Emphasises animal’s abilities to make economic decisions
● For human behaviour: how cultures vary due to ecological pressures
● Williams, Smith, Krebs, DeVore, Symons
Sociobiology
● Grew out of ethology in 1960’s/1970’s, overlaps with behavioural ecology
● Evolution of social behaviour
● Uses functional explanations of pro/antisocial behaviour → how current behavioural responses
occur because of usefulness to ancestors
● Human social organisation developed through natural selection
● Interested in nonhuman species
● Wilson, Hamilton, Trivers, Thornhill
Evolutionary psychology
● Takes sociobiology principles + cognitive mechanistic view of mind: modularity
● Uses experimental studies (or survey data) to test predictions from evolutionary theory
● Focus of explanation: psychological mechanisms (unlike other 3 disciplines)
● Tooby, Cosmides, Buss, Pinker
Sigmund Freud
● Cultural relativism: great emphasis on role of parents + family in shaping personality
● Interested in ultimate questions: why people behave a certain way
● Some of his ideas in line with recent Darwinian psychology → The ‘id’ as a set of inborn desires
(incl. Sexual imperative) has many parallels with evolutionary theory
, E.O. Wilson 1975: “sociobiology the new synthesis”
● Foundation modern evolutionary approach to the study of behaviour
● If behaviour affected reproductive success in a predictable way + if particular behaviours were
influenced by genes → natural selection helped shape human behaviour
Evolutionary psychology
● Is sociobiology rebranded so it’s more politically accepted
Evolutionary psychology; Tooby + Cosmides 1992
● Difference sociobiology: adopts cognitive level of explanation
● Explain human behaviour by underlying computations in the mind
Sociobiology, evolutionary psychology, political correctness
● Sociobiology seen as dangerous thinking, like eugenics
● 1986: twenty social scientists made Seville Statement of Violence: to contradict link between
biology + violent behaviour
Seville Statement of Violence; Scientifically incorrect
● We inherited tendency to make war from animal ancestors
● War/violent behaviour is genetically programmed
● In human evolution, there’s a selection for aggressive behaviour more than other kinds
● Humans have a violent brain
● War’s caused by instinct or any single motion
Tooby + Cosmides 1997; 5 principles of evolutionary psychology
● Brain’s a physical system: it’s circuits generate behaviour appropriate to environmental
circumstances (cognitive psychology)
● Neural circuits designed by natural selection to solve problems during our evolutionary history
(sociobiology)
● Conscious experience can mislead us to think our circuits are simpler than they really are
(cognitive psychology)
● Different neural circuits specialised for solving different adaptive problems (modularity)
● Our modern skulls have stone-age mind (modularity)
David Buller; Differences between
● Evo. Psy. as field of research → understanding relationship between evolution + behaviour
● Evo. Psy. as research paradigm → makes assumptions about modularity + EEA (Santa Barbara
School)
Franz Joseph Gall; Modular Psychological Theory
● Mind made up of specific mental organs/faculties → each responsible for aspect of behaviour (37
different faculties)
● Bumps on cranium: read person’s characteristics by feeling the size (phrenology)
Jerry Fodor; Modularity of the mind
● Mind made up of mental modules → each responsible for certain aspects of human behaviour
● Modules are innate, changed little over lifetime
One criticism of Buller on modularity
● Little neurological evidence for mental modules in neocortex: part of brain most closely
associated with behaviour
EEA: Environment of Evolutionary Adaptiveness
Smith’s cause for concern about EEA
● Not helpful in understanding behaviour
● What characterises human behaviour → ability to deal with novelty through problem solving,
language, cultural learning: all evolved
● Differences from Santa Barbara School: extent to which stone-aged mind (if it exists at all)
constrains current + future behaviour
