Week 8 Lecture 7 - cooperation

Question 1

What did Hamilton create?

Answer 1

Payoff matrix
- 4 social interactions between 2 individuals
- gains and losses (payoffs) in terms of fitness

Question 2

Altruism is “that which should not evolve” why?

Answer 2

because actor suffers a fitness cost for others
not beneficial to actor

Question 3

Why is cooperation a problem?

Answer 3

• free-riders share the benefits but not the costs
• this is true for mutualism as well as altruism

Question 4

Did Darwin recognise altruism as a problem?

Answer 4

yes

Question 5

What is inclusive fitness?

Answer 5

total fitness of an individual’s genes equals:
- direct fitness (personal reproduction)
+
- indirect fitness (additional reproduction by relatives)

Question 6

Are inclusive fitness and kin selection the same thing?

Answer 6

yes

Question 7

What is Hamilton’s rule?

Answer 7

an act has a cost for the actor (donor) and benefits for the recipient

Question 8

When does spread of a gene for altruism occur?

Answer 8

c< r b

b = benefits to recipient
r = coefficient of relatedness
c = cost to actor

Question 9

Hypothetically, what are greenbeards?

Answer 9

produce an observable trait, such as altruism, would then act altruistically towards them.

Question 10

What is the problem with greenbeards?

Answer 10

• 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

Question 11

Can kin selection explain a great deal of altruistic behaviour?

Answer 11

yes including the evolution of sterile worker castes

Question 12

When is kin selection not applicable?

Answer 12

when considering large societies of unrelated individuals e.g., people striking

Question 13

Natural selection should promote genetic selfishness. Give an example of why this isn’t the case

Answer 13

people are kind to strangers e.g., donating blood

Question 14

What is classical group selection?

Answer 14

we are kind to strangers for the good of the species

Question 15

What is an issue with classical group selection?

Answer 15

• 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)

Question 16

Who had the idea of reciprocal altruism?

Answer 16

Trivers

Question 17

What is reciprocal altruism (direct reciprocity)?

Answer 17

• cost should be lower than the benefits
• benefits should be delayed

Question 18

What are the requirements for reciprocal altruism?

Answer 18

• interact often
• be able to recognise one another and keep accounts
• be able to act contingently

Question 19

Does direct reciprocity occur often in nature?

Answer 19

no, very rare in nature
even though cognitive demands are often met

Question 20

What is mutualism (cooperation)?

Answer 20

benefits both individuals immediately

Question 20

Are free-riding and exploitation still problems for mutualism?

Answer 20

yes

Question 21

What is indirect reciprocity?

Answer 21

• help others to build a reputation (downstream)
• help others as a form of niceness (upstream)

Question 22

What is an example of indirect reciprocity?

Answer 22

maybe someone else will give blood to you

Question 23

What is generalised reciprocity?

Answer 23

• altruism without expectation of return
• also called attitudinal reciprocity or “warm glow” altruism

Question 24

What is negative reciprocity?

Answer 24

- punishment - inflicting harm for harm done - important for deterring free-riders - third-party punishment particularly important and possibly uniquely human

Question 25

Do chimpanzees show negative reciprocity?

Answer 25

no but children do

Question 26

What is strong reciprocity?

Answer 26

cooperate with others and punish noncooperators

Question 27

What is reciprocity essential for in humans? What forms?

Answer 27

- reciprocity is essential for hunter-gathers - both positive and negative reciprocity

Question 28

Who does better? Groups with altruists or groups without?

Answer 28

groups with

Question 29

What can between group competition lead to in certain conditions?

Answer 29

the evolution of altruism under certain conditions

Question 30

What is cultural group selection?

Answer 30

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

Question 31

What is game theory?

Answer 31

decision-making in context of interactions with other agents cost and benefits of each action depend on the choices of others

Question 32

What does game theory assume?

Answer 32

- rationality --> assumes that all players are rational and that they know that all other players are rational - assumption of utility maximisation

Question 33

What is utility?

Answer 33

measure of satisfaction from consuming a good measured as the price someone is willing to pay to satisfy a desire

Question 34

What is nash equilibrium?

Answer 34

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

Question 35

What is evolutionary stable strategy?

Answer 35

a strategy that can resist invasion by any other available strategy, provided each other strategy invades alone and the small numbers

Question 36

An equilibrium can exist is there is no better alternative strategy What is an example of this?

Answer 36

the prisoner's dilemma

Question 37

How can co-operation arise from a prisoner's dilemma?

Answer 37

- 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

Question 38

What is cold cognition?

Answer 38

reason - recognise one another - keep accounts - keep track of relationships of others - act contingently - recognise intentions and goals of others

Question 39

What is hot cognition?

Answer 39

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

Question 40

What two outcomes can hot cognition have?

Answer 40

- aligned fortunes-of-others emotions can motivated prosocial behaviour - but other-regarding concerns can be misaligned leading to antisocial behaviour