Week 8 Lecture 7 - cooperation Flashcards
What did Hamilton create?
Payoff matrix
- 4 social interactions between 2 individuals
- gains and losses (payoffs) in terms of fitness
Altruism is “that which should not evolve” why?
because actor suffers a fitness cost for others
not beneficial to actor
Why is cooperation a problem?
- free-riders share the benefits but not the costs
- this is true for mutualism as well as altruism
Did Darwin recognise altruism as a problem?
yes
What is inclusive fitness?
total fitness of an individual’s genes equals:
- direct fitness (personal reproduction)
+
- indirect fitness (additional reproduction by relatives)
Are inclusive fitness and kin selection the same thing?
yes
What is Hamilton’s rule?
an act has a cost for the actor (donor) and benefits for the recipient
When does spread of a gene for altruism occur?
c< r b
b = benefits to recipient
r = coefficient of relatedness
c = cost to actor
Hypothetically, what are greenbeards?
produce an observable trait, such as altruism, would then act altruistically towards them.
What is the problem with greenbeards?
- if an observable trait is associated with a behaviour, these genes are likely separate and can be shuffled
- this means that you would end up being kind to people who aren’t nice
- This is why we tend to be kinder to people more closely related to us
Can kin selection explain a great deal of altruistic behaviour?
yes including the evolution of sterile worker castes
When is kin selection not applicable?
when considering large societies of unrelated individuals e.g., people striking
Natural selection should promote genetic selfishness. Give an example of why this isn’t the case
people are kind to strangers e.g., donating blood
What is classical group selection?
we are kind to strangers for the good of the species
What is an issue with classical group selection?
- if you do things for the good of the species, free-riders will benefit
- benefits have to go to the individual (more specifically the individual’s genes)
Who had the idea of reciprocal altruism?
Trivers
What is reciprocal altruism (direct reciprocity)?
- cost should be lower than the benefits
- benefits should be delayed
What are the requirements for reciprocal altruism?
- interact often
- be able to recognise one another and keep accounts
- be able to act contingently
Does direct reciprocity occur often in nature?
no, very rare in nature
even though cognitive demands are often met
What is mutualism (cooperation)?
benefits both individuals immediately
Are free-riding and exploitation still problems for mutualism?
yes
What is indirect reciprocity?
- help others to build a reputation (downstream)
- help others as a form of niceness (upstream)
What is an example of indirect reciprocity?
maybe someone else will give blood to you
What is generalised reciprocity?
- altruism without expectation of return
- also called attitudinal reciprocity or “warm glow” altruism
What is negative reciprocity?
- punishment
- inflicting harm for harm done
- important for deterring free-riders
- third-party punishment particularly important and possibly uniquely human
Do chimpanzees show negative reciprocity?
no but children do
What is strong reciprocity?
cooperate with others and punish noncooperators
What is reciprocity essential for in humans? What forms?
- reciprocity is essential for hunter-gathers
- both positive and negative reciprocity
Who does better?
Groups with altruists or groups without?
groups with
What can between group competition lead to in certain conditions?
the evolution of altruism under certain conditions
What is cultural group selection?
groups of individuals compete with other groups of individuals
groups of co-operators are more successful than groups of noncooperators
but is more complex than this as it can lead to free-riders benefitting
What is game theory?
decision-making in context of interactions with other agents
cost and benefits of each action depend on the choices of others
What does game theory assume?
- rationality –> assumes that all players are rational and that they know that all other players are rational
- assumption of utility maximisation
What is utility?
measure of satisfaction from consuming a good measured as the price someone is willing to pay to satisfy a desire
What is nash equilibrium?
a set of strategies in which each is a best response to other strategies
no individuals can do better by changing his strategy relative to the behaviour of the other strategies
What is evolutionary stable strategy?
a strategy that can resist invasion by any other available strategy, provided each other strategy invades alone and the small numbers
An equilibrium can exist is there is no better alternative strategy
What is an example of this?
the prisoner’s dilemma
How can co-operation arise from a prisoner’s dilemma?
- repeated games
- iterated prisoner’s dilemma
- winning strategy was tit-for-tat however, if number of rounds is known, backwards induction leads rational players to always defect
What is cold cognition?
reason
- recognise one another
- keep accounts
- keep track of relationships of others
- act contingently
- recognise intentions and goals of others
What is hot cognition?
emotions
- short cuts (heuristics) might guide our decisions
- emotions can serve as “barometers” of our social decisions
- a warm-glow isn’t an end in itself, but a measurement of whether we have achieved a desired outcome
What two outcomes can hot cognition have?
- aligned fortunes-of-others emotions can motivated prosocial behaviour
- but other-regarding concerns can be misaligned leading to antisocial behaviour
