Psych 385 Class 8 Nov 17

What is needed for evolution to occur?

What are the basic requirements needed for evolution to occur and how can they be met by genes and cultures? Darwin is known to have underestimated what? Some change is possible in how many generations for humans? 

• Sufficiently Large Population 

• Sufficient phenotypic variation in population 

• Environmental change relatively slow

• Relatively slow decline in population 

• Darwin: the speed of evolutionary change speed 

• 1 generation= 20-30 years? 25? 

• Some change possible in 50-100 generations

• EX. as quickly as 1-2k years for humans under strong selection pressure 

• EX. Lactase persistence as quick as 3000 years

The Pace of Evolution: What is the current thinking that human evolution might be actually what? What is driving this? Larger population means more what? What is a primarily driver? Cultural ______? 

• “speeding up”

• Population increase partly driving this:

• Larger population (8.25B) means more potential variation in phenotype on which selection can act 

• A primarily driver is the Spread of civilization (ESP in last 30k-40k years): Confirmed by human genome project showing 10% of genes under strong selection last 50k

• Cultural innovation (esp. in the last 10k or so with the advent of modern agriculture) 

• In Holocene: current geological epoch??? 

To what extent does it make sense to separate Cultural Evolution and Gene-Culture Coevolution and why?

How and why can the subfield of memetic be seen as a cautionary tale for subfields of evolutionary psychology?

How does culture transcend individual learning in the case of Cultural Evolution vs. Human Behavioural Ecology? 

How do Boyd and Richerson (1985) explain the evolution of social learning and what is its theoretical relevance?

Why do Brown and Lala argue that EP is committed to a unidirectional causal arrow from gene to culture and what are the consequences of taking such a view?

What are the Benefits of Social Life? (4 Things)

• Anti-Predation: Through dilution in group, increased vigilance, escape confusion, and reactive aggression

• Group foraging and hunting: Net individual benefit greater than individual forager/hunter alone (but can be exceptions)

• Defence of territory and even offspring: Particularly good if a niche can support the group & a creche: caring for another’s offspring

• Social Learning (Cornerstone of cultural evolution): Observe things that work for others vs. relying on your own trial and error for learning

What are the Major Costs of Social Life? 

• There musts be costs to group living or else all species would be social and they are not

• Contagion risk, but resource depletion is big one since costly to move around a lot more

• Catch viruses, when you’re alone, the time you spent alert is at the highest, you cannot forage because you gotta pay attention, for individual animals were less alert when they are in big group size

Social Mating Systems: 4 of them? What type of social mating have larger brains?

• Monogamy: Males and females have one mate only (at least per mating season) 

• Polygyny: Male and several females (Harem) 

• Polyandry: Female and several males (ducks) 

• Promiscuity: multi-male and multi female 

Silverback gorilla

• Lemurs are monogamous

• For Monogamous or polygnous: Track social info over time!

• For Promiscuous: Don’t need to track social info, predict smaller brains, don’t have the same computational demands

• Monogamy and harem are larger brains

How strong is the Evidence for the Social Brain Hypothesis?

apes and monkeys, group size plotted against size of neocortex volume 

What is Kirkwood’s disposable soma theory? Self-repair could theoretically slow what? Reproductive success is what?

• Aging and death as a result of unrepaired damage to body cells

• (Soma-parts of organism OTHER THAN reproductive cells)

• Slow this damage and even remove it altogether

• But the energy to do this could instead be used on reproduction

• RS success: is higher when forgoing perfect self-repair in favour of reproduction

Dunbar and Sosis (2018): on Hierarchy: They use stability of what sizes in how many small scale societies? to show that ground sizes ___, ____,&____ naturally emerge like in _______-_______? What are 2 things they suggest?

• Stability of community sizes in 3 small scale societies to show that group sizes of around 50, 150, and 500 naturally emerge like HUNTER-GATHERERS

• They suggest that the need for social control and specialized roles (hierarchy) also naturally emerges in groups over 500

• (therefore Cosmides and Tooby’s video about us being natural socialists mismatched in a modern world is not so crazy!!)

Religion and Cooperation: Challenges to cooperative behaviour are well known in what literature?

• Evolutionary literature

What is the Cultural evolutionary take on religion?

• It gives a way to explain existence of large-scale cooperation, which can’t really be explained by direct or indirect reciprocity (and seems impossible for Cosmides and Tooby)

• The concept of “moralizing gods” thought to stabilize cooperation levels in large groups of anonymous individuals, where “repetitional and reciprocity incentives are insufficient”

• Religious people seen as more trustworthy

• Belief in same gods facilitates cooperation

• Also creates selection for costly displays of sincere religious commitment (rituals, fasting)

Recouping that investment in large brains and back to Dawkins’ Vehicle VS. Replicator? 

What is Senescence and sources of morality?