PSYCH 317: Cultural Evolution

Social learning

Learning that is influenced by observing or interacting with another animal (usually a member of the same species) or the products of their behaviour

Why is social learning important for humans

It allows knowledge, behaviours, and traditions to spread rapidly through populations, creating cultural diversity that cannot be explained by genetics alone

What process links social learning to cultural diversity

Learning —> traditions —> divergence of traditions —> cultural diversity

Why are humans considered social learners

Humans acquire behaviours, knowledge, norms, and traditions through observing and interacting with others

Why is social learning particularly important in humans

Human cultures change rapidly and spread into diverse environments, requiring flexible learning beyond genetics

What did Lewontin (1972) find about human genetic variation?

~85% of human genetic variation occurs within populations rather than between populations

What does Lewontin’s (1972) finding suggest about cultural diversity

Large cultural differences cannot be explained by large genetic differences

Why is genetic diversity alone insufficient to explain human behavioural diversity

Humans have relatively little genetic variation despite enormous cultural variation

What are the three major evolutionary strategies for shaping adaptive behaviour Boyd and Richerson (1988)

• Species-typical responses (genetics)

• Individual learning (trial and error)

• Social learning

3 major evolutionary strategies for shaping adaptive behaviour: species-typical response

An adaptive behaviour that is genetically inherited and common across members of a species, which helps organisms survive in their environment

3 major evolutionary strategies for shaping adaptive behaviour: individual learning

Learning through personal trial and error experiences

3 major evolutionary strategies for shaping adaptive behaviour: social learning

Learning adaptive behaviours from others rather than through genetics or personal experience alone, explaining the vast cultural diversity amongst humans

Why is social learning considered a third evolutionary strategy

It allows adaptive information to spread rapidly through populations without requiring genetic change

Historically, why did researchers question whether social learning makes humans unique

Because many forms of social learning have also been observed in non-human animals

Which species was studied by Fisher & Hinde (1949)

British tits (small birds)

What novel behaviour appearred in British tits in 1921

Opening milk bottle tops to access milk

Where was milk-bottle opening first observed

Swaythling, England

Why was milk-bottle opening considered innovative

It allowed birds to exploit a new food resource

What happened by 1939 and 1947 (milk bottle top opening by British tits)

• 1939: The behaviour had spread throughout northern England

• 1947: the behaviour had spread across most regions of Britain

Why couldn’t milk-bottle opening be explained genetically

The behaviour spread far too quickly

Why couldn’t milk-bottle opening be explained by individual learning alone

The pattern of spread suggested transmission between individuals

What is the best explanation for the spread of milk-bottle opening

Social learning

What are the different forms of social learning (from least to most cognitively challenging)

• Local/stimulus enhancement

• Emulation

• Imitation

1) Different forms of social learning: Local enhancement

Attention is drawn to a particular location because of another individual’s behaviour

1) Different forms of social learning: Stimulus enhancement

Attention is drawn to a particular object because of another individual’s behaviour

1) Different forms of social learning: What is the key feature of local/stimulus enhancement

It does not require copying behaviour

1) Different forms of social learning: What is copied in local/stimulus enhancement

Attention, not actions

1) Different forms of social learning: What bee experiment demonstrates local/stimulus enhancement

A trained bee learned to operate a complex apparatus to obtain a reward, directing the attention of colony members who then learned the task

1) Different forms of social learning: What does the bee study show (local/stimulus enhancement)

Simple social learning mechanisms can support cultural traditions

2) Different forms of social learning: What is emulation (Tomasello, 1990)

Learning about case-effect relationships and outcomes rather than copying actions/behevaiour

2) Different forms of social learning: What phrase summarises emulation

“copy the results”

2) Different forms of social learning: what is an example of emulation

Seeing a fit person leave the gym and pursuing fitness using your own methods

2) Different forms of social learning: What is copies during emulation

The goal or outcome

2) Different forms of social learning: What cognitive skill is involved in emulation

Understanding intentions and cause-effect relationships

3) Different forms of social learning: What is imitation

Acquiring a novel behaviour by copying the demonstrator’s motor actions

3) Different forms of social learning: What phrase summarises imittaion

Copy the actions

3) Different forms of social learning: What is an example of imitation

Copying the movements of a skilled athlete

3) Different forms of social learning: What is copied during imitation

The exact behavioural technique

3) Different forms of social learning: Why is imitation cognitively demanding

It requires accurate reproduction of another individual’s motor patterns

3) Different forms of social learning: chimpanzee imitation study AIM

Whiten, Horner, & de Waal (2005)

• Tests whether the social learning of chimpanzees is underpinned by emulation or imitation

3) Different forms of social learning: chimpanzee imitation study METHOD

• apparatus: a puzzle box containing a food reward that can be opened using two techniques

  • poke

  • lift

• a high-ranking female was trained in either poke or lift and returned to the group

3) Different forms of social learning: chimpanzee imitation study PREDICTIONS

• emulation would predict that group members would use whichever method worked

• imitation would predict that group members would copy the demonstrated technique

3) Different forms of social learning: chimpanzee imitation study RESULTS

most group members were successful

• poke group: most continued using poke method even after 2 months

• lift group: some individuals later switched to poke

3) Different forms of social learning: chimpanzee imitation study CONCLUSION

Chimpanzees imitate specific actions, not merely emulating outcomes

3) Different forms of social learning: great tit study AIM

Alpin et al (2015)

• Tests whether the social learning of great tits is underpinned by emulation or imitation

3) Different forms of social learning: great tit study METHODS

• demonstrator birds taught two methods to access food

  • Option A: moving door left-to-right

  • Option B: moving door right-to-left

• release birds

3) Different forms of social learning: great tit study RESULTS

Imitation can create traditions in wild animal populations

3) Different forms of social learning: what important conclusion follows from the chimapnzee and great tit studies

Imitation is not uniquely human

What is the Ratchet Effect

Improvements remain in the population and provide a foundation for future innovations

Why is it called the Ratchet Effect

Cultural knowledge tends to move forward rather than slipping backward

What is the significance of the Ratchet Effect

It allows cumulative cultural evolution

What does cumulative culture allow

New generations can build on previous innocations rather than starting from scratch

Give an example of the Ratchet Effect

One person invents a tool, another improves it, and the improved version spreads throughout the population —> etc,.

Is teaching unique to humans

No

Why do meerkats challenge the idea that teaching alone explains cumulative culture

Meerkats teach but do not develop increasingly complex technologies, which shows that teaching may be necessary but is not sufficient for cumulative culture

What was the aim of the stone-tool transmission experiment

To identify which forms of social learning best support transmission of complex skills

stone-tool transmission experiment: transmission chain

A sequence in which each participant learns from the previous participant

stone-tool transmission experiment: reverse-engineering condition

Participants saw the finished flakes and inferred how they were made

stone-tool transmission experiment: imitation/emulation condition

Participants observed tool-making but could not communicate

stone-tool transmission experiment: basic teaching condition

Tutors demonstrated actions and physically guided learners

stone-tool transmission experiment: gestural teaching condition

gestures were allowed, but speech prohibited

stone-tool transmission experiment: verbal teaching condition

speech, gestures, demonstrations, and guidance were all permitted

stone-tool transmission experiment: what happened as teaching became more sophisticated

Tool-making performance improved

stone-tool transmission experiment: which condition produced the highest number of flakes

verbal teaching

what does the stone-tool transmission experiment suggest about language

Language dramatically improves transmission of complex cultural skills

What are the two inheritance systems in humans

• genetic inheritance

• cultural inheritance

What is genetic inheritance

Transmission of information through DNA

What is cultural inheritance

Transmission of socially learned behaviours, norms, values, institutions, and knowledge

Why is cultural inheritance powerful

Individuals can acquire information they could not discover alone

What new possibility does cultural inheritance create

Cultural evolution

How does cultural evolution differ from genetic evolution

Cultural traits can spread and change much more rapidly than genetic traits

Which forms of social learning are shared with other animals, and what may make humans unique

• Animals share local enhancement, stimulus enhancement, emulation, imitation, and even teaching with humans.

• Humans appear unique because language enables highly accurate transmission of information, supporting cumulative culture and Ratchet Effect, whereby innovations accumulate and improve across generations