5. Cooperation & Altruism Flashcards
What behaviours (as a result of evolution) benefit our genes?
Status seeking Competition Aggression Grooming Food sharing Charitable donations?
Traditional view of altruism
Due to group selection (people believed individuals acted for the good of the group)
However, any selfish individual invading a group of ‘complete’ altruists will benefit
If not group selection, must be other specific circumstances where altruism evolved
Early theories of evolution of altruism
Kin selection
Reciprocal altruism
Which early theory of evolution of altruism explains cooperation between non-relatives?
Reciprocal altruism
Examples of reciprocal altruism
Food giving among Hiwi and Ache families is based on reciprocity
Everyday examples in UK (childcare, buying drinks, peer support)
Male baboons help each other usurp higher ranked males to gain access to fertile females
Vampire bats share blood
Injured dolphins supported by non-relatives
Monkeys warn of predators with alarm calls
What are the conditions for reciprocal altruism?
- the cost of the altruistic act MUST be less than the benefit received later
- species capable of RA must be highly social (live in groups)
- species must have appropriate cognitive abilities (remember past interactions, learn from them)
In which species is reciprocal altruism most likely to occur according to the conditions for RA?
Humans and other primates
How can we experimentally examine reciprocal altruism?
Economic games
Prisoner’s Dilemma
2 players make decisions simultaneously + confidentially
Decision they make and their partner makes affects benefits they receive
Prisoner’s Dilemma: one-shot
always ‘defect’
this strategy guarantees a return (but not as beneficial as if both cooperate)
Prisoner’s Dilemma: iterated
best strategy is for both players to continue to cooperate (more beneficial)
Who organised the Prisoner’s Dilemma tournament?
Robert Axelrod (1981)
What was the purpose of the Prisoner’s Dilemma tournament?
Different strategies pitted against each other to determine the best way to play the iterated PD game
What is the best strategy for the Prisoner’s Dilemma?
TIT-FOR-TAT
Nice: cooperate on the first go
then copy what the opponent did on their last go…
Retaliatory: sees cheating and cheats too
Forgiving: forgives earlier cheating if opponent begins cooperating again
Choosing cooperative partners: evidence for physical attractiveness
Attractive people cooperated with more and more expected from them (Solnick & Schweitzer, 1999)
Also viewed as more trustworthy and punished more when they are not (Wilson & Eckel, 2006; Andreoni & Petrie, 2008)