Culture and social networkds Flashcards
What is culture
Cultures = group-typical behaviour patterns shared by members of a community that rely on social learning and socially transmitted information [Laland 1994]
Culture = a second inheritance system (extra-genetic inheritance) and can lead to cultural evolution
Importance of cultural systems
Adaptive:
- Culture can be adaptive or can be arbitrary/ maladaptive if it allows bad behaviours to spread eg. chimp wears grass in her ear then all others copy = no fitness benefit
Gene-culture co-evolution:
- Example: Westerners eat lots of dairy and genes allow lactose digestion
Conservation:
- Important to consider for species re-introduction as organisms lack knowledge needed to survive
- many ungulates rely on culture + social learning to learn migration routes
- Example: it took 90 years or 12-13 generations for 50% of descendants of translocated Elk in USA to become migratory
Human success:
- culture is instrumental for human siccess
- cumulative cultural evo: not immediate success but success over years of developing culture eg. no single human gen achieves space travel but over many we have.
How to identify culture: Ethnographic method
Behavioural variants in different areas/groups are documented, and possible alternative explanations (e.g. ecological or genetic differences) are excluded
Criteria:
1) Socially transmitted
2) Cannot be explained by genetic adaptations
3) Cannot be explained by environmental differences (exclusion of eco factors)
Example: Chimps
- 39 cultural variants of chimps across 6 field sites
- hard to entirely exclude eco / genetic factors
- Env factor ignored: different tool use required for different ant species in chimps and some ants only found in certain regions
- Gen factor ignored: 1/3rd chimp variants are in 1 sub-species
Example: Orangutang
- cultural distance correlates w/ geographical distance (if closer then more migrants and more cultural homogenisation)
Example: Meerkats
- Study looked at sleep patterns for 7 years
- some groups consistently emerged later from their sleeping burrows than others despite complete turnover and influex in immigrants
- extensive gene flow precludes genetic differentiation.
Criticism
* Other factors can never be absolutely excluded – relies on circumstantial evidence
* We actually expect behaviour and env / genetics to be correlated as behavior is adaptive (so why do we exclude these factors?)
* Genetic explanations ignored – may find more variants in one sub-species than another
* Ecological interpretations ignored
How to identify culture: Translocation experiments
indivs moved between groups, or whole groups are swapped (movement can occur naturally or be experimentally enforced)
Natural
Example: Blue headed wrasse
- blue-headed wrasse mating sites = stable over 12 years w/ females visiting male arenas
- translocated entire local pop’ns between reefs then found new sites which became stable over next years –
- shows mating sites have no special properties, but are just traditional sites established via cultural transmission between females -> if tradition broken, new sites established
How to identify culture: Social network diffusion method
New behaviours are monitored as they diffuse through the social system (allows post-hoc identification of social learning)
Network-Based Diffusion Analysis:
- spread of a socially transmitted target behaviour should follow connections of social network, reflecting social learning opportunities
- Compare diffusion to models based on social network, genetics and environmental factors
Natural example: Lobtail feeding in humpback whales
- slam tail on surface of water to prevent fish jumping out of water before chase from below and make bubble mist net to enclose )
- emerged in 80s in one indidvual and seen in 278 by 2007
- Analyses showed that behvaior spread through social learning
Natural example: transmission of moss or leaf sponging to drink water in Chimps
- NBDA showed a 15-fold increase in learning rate each time uninformed chimp observed an informed chimp
Expermental example:
- Experimentally introduce innovative door pushing behaviour ( birds move blue door left or move red door right to access food)
- Release into pop’n and see how behaviour spreads
- Track / predict spread by tagging birds + tracking who interacts w/ who at feeders -> can construct social network ->
- Results: information spread rapidly through social network ties and was stable despite high turnover.
- Those who don’t learn from the 2 indivs will eventually learn themselves to open door but will push left 50% of time and right the other 50%
Culture + associative learning
An organisms can learn something through associative learning and then it can spread through the colony through social.
Example: String-pulling in bumblebees
- Bees pull string to acces reward
- bees observed other bees pulling string so copy that behaviour
- behaviour spreads in colony + across generations
- even when lose initial trained bee get secondary transmission from a secondary learner
Culture produces social structure, or social structure produces culture?
If separate groups develop different behaviours -> social structure influences cultural development
Eg. bottlenose dolphins use sponge on rostra as protection when rummaging in debris in Shark bay Australia – mother-offspring transmission so social structure shapes culture (as different groups have different behaviours)
If different behaviours (cultures) drive separation between groups -> culture influences social structure (indivs preferentially associated w/ those who behave similarly)
Eg. sponge using females associate more strongly together -> culture shaping social structure
Limitations of study
- Observe dolphins from a boat where they tend to be in groups.
- But ID dolphins as spongers when they are carrying a sponge and they only sponge when they are by themselves.
Summary
Importance of cultural systems
- Adaptive:
- Gene-culture co-evolution:
- Conservation:
- Human success:
Methods to study
- ethnographic
- translocation
- social network approaches
