1. Cultural Evolution Culture: “Activities, values & behavior of individual acquired through instruction or imitation” Transmission via social learning Cavalli-Sforza et al. (1982) Science 218:19.

2. Cultural Evolution Cultural traits : socially learned phenotype Cultural transmission: Recipient acquires trait from transmitter Cultural evolution: Change in frequency of cultural traits over time

3. Cultural Evolution Some parallels with biological evolution Dynamics of traits: Population genetics More like spread of disease? Mutation: Cultural innovation, or random change in trait expression

4. Cultural Transmission Change/acquisition behavior or attitude Recipient learns socially Transmitter active or passive Teaching, conditioning, imitation, etc. Model, mimic

5. Dynamics of Cultural Evolution Mode & Number transmitters/receiver Modes: Vertical: Parent to offspring Horizontal: Within generation (sibs) Oblique: Non-parents of generation t to generation (t + 1)

6. Dynamics of Cultural Evolution Transmitters/receiver Many to one (All adults instruct) One/few to few (Vertical, horizontal) One to many (Oblique)

7. Dynamics of Cultural Evolution Questions Heterogeneity, diversity (polymorphism) Within population Between populations (low dispersal rate) Rate of cultural evolution (selection, neutral)

8. Predictions: Cultural Evolution Assume: Many to one transmission Little cultural diversity Difficult for invasion by novelty Within-population heterogeneity low Between-population heterogeneity low Slowest cultural change

9. Predictions: Cultural Evolution Assume: One to many transmission Little cultural diversity Rapid advance of novelty (turnover) Within-population heterogeneity low Between-population heterogeneity high Fastest cultural change

10. Predictions: Cultural Evolution Assume: One to few transmission High cultural diversity Within-population heterogeneity high Between-population heterogeneity high Intermediate rate cultural change

11. Cultural Transmission: Humans Stanford students Assume: One to few transmission Vertical, Parent to Offspring Correlate Cultural Traits Assume no genetic transmission No fitness consequences

12. Cultural Transmission: Humans

13. Assume: Vertical, Parent to Offspring Religion: Strongest Correlations PoliticsEntertainmentSportsBeliefs Habits: Weakest Correlations

14. Cultural Transmission: Humans Assume: Vertical, Parent to Offspring Religion: Stronger correlation through mother Politics: Strong correlation through father What Evolves? Traits and/or transmission modes?