Lecture 3 - reciprocity Flashcards
who was the idea of reciprocity devised by?
bob trivers (1971)
what phrase is reciprocity exemplified by?
‘you scratch my back, ill scratch yours’
what theory underpins reciprocity?
the prisoners dilemma game - 2 players in a game with choice of ‘cooperate’ or ‘defect’
what are the 4 possible outcomes in the prisoners dilemma matrix?
R = mutual cooperation reward – both have a cost but also both gain T = temptation to defect – if they defect a co-operator they get only pay off and have no cost S = if you cooperate with a defector you only get cost P = you defect a defector you are both punished
in a population of defectors what is the best option?
the best option is too defect - in a one off interaction the best ESS (strategy) will be too defect
Can reciprocity work and can individuals escape this dilemma?
NO…. if single encounter, or fixed number of encounters, defect is always ESS
YES… can work with repeated, indeterminate
encounters
describe the ‘tit for tat’ strategy
- cooperate on first move, then do what partner did
- can be ESS if probability of re-encounter is high
- depends on social organisation, longevity, etc
- the conditions for this tit for tat strategy may actually be quite widespread in nature
describe the text book example of reciprocity in vampire bats?
- In roosts the bats form, unsuccessful foragers are fed by successful ones
- Within the roosts - there is low kinship overall - low average relatedness, however the kin were more likely to swap blood(food) than the others
- But the 3 key facts that point towards reciprocity taking place are:
1) high chance of future interaction (always come back to the same roost)
2) benefit to recipient high, cost to donor low
3) donation is reciprocated (observed during study)
what has been criticised by the wilkinson study on vampire bats?
- sharing is kin-selected
- sharing with non-kin is coercion, mistaken identity or indiscriminate altruism within kin groups
Carter and Wilkinson (2013) then did another study
The question was then asked of what blood donation depended on what were the possibilities?
1) blood recieved
2) Grooming received
3) Donor sex
4) relatedness
what was the result of the second study carried out by carter and wilkinson?
blood donation depended on blood received supporting the reciprocity interpretation
what is an example in primates of reciprocity?
Primate grooming and alliances - grooming tends to be reciprocated between individuals - however it’s hard to know if its reciprocal or mutualistic behaviour because they two individuals often take part in the act at the same time
- relatively few studies in primates
describe the best example of reciprocity in birds
- Experiment involved 3 pairs of flycatchers occupying next boxes
- At one nest box they caught the pair and put them In a cage
- They then presented a stuffed owl at a nest box and the pair started mobbing the owl - another pair not in the cage then also joined in the mobbing
- Then when owls were placed at the two other pairs (one of which now out the cage)
- The original pair then went to help the pair which helped them with the mobbing the first time - reciprocating the behaviour
- The original pair never helped the pair that didn’t help them the first time around
what are the 3 general conclusions about reciprocity
- Limited evidence in natural systems (Clutton-Brock 2009; but see Taborsky et al. 2016 - strong advocate for the idea)
- Interactions are rarely dyadic
- instead individuals will develop profitable relationships
and terminate unproductive ones
3.Defection PUNISHED / cooperation ENFORCED
- Cheating has high costs
what theory has the idea that interactions are rarely dyadic been formulated in?
The Biological market theory (Noë & Hammerstein 1994, 1995)
describe The Biological market theory (Noë & Hammerstein 1994, 1995)
this idea borrows from economic theory and views individuals as holders of and seekers for social commodities
Holding class - holds access to social commodity
Demanding class - seeks access to social commodity
Trade dynamics- supply and demand, advertisement, commodity value
describe an example of the biological market theory?
Macaque mating market (Gumert 2007) - looked at male-to-female grooming in relation to number of females in the population
-The more females in the population the less time the males spent-
Grooming duration related to supply of females
the bioligical market leads to different kinds of reciprocity what are they?
1) Direct reciprocity - you scratch my back, ill scratch yours’
2) Generalised reciprocity - help anyone if helped by someone - can work in theory, one good supportive lab expt
3) Indirect reciprocity
‘Help someone who is helpful’
-Reputation may be important in social interactions
-Can work in theory, some evidence
describe the lab experiment supporting generalised reciprocity
Norway rats in lab (Rutte & Taborsky 2007)
- Trained rats in cooperative and non- cooperative environements
- If they had previously experienced a positive cooperative social environment their frequency of helping others was 21% higher
describe the experiment on dinoponera ants to understand in punishment prevents cheating?
- Live in relatively small colonies
- No single queen
- Queue of females waiting to become the dominant (alpha) female which is the only one that reproduces - important to get to the top of the queue - the alpha Is challenged by the beta female
- If challenged, alpha marks challenger (with pheromone) who is then PUNISHED by other females - once punished they don’t challenge the queen again
the idea of punishment for cheating has also been tested in humans describe experiment
- Honesty box for when you use milk, sugar etc in coffe room
- Put pictures up around the honesty box
- Analysed how much money was put in the box depending on the pictures placed above
- Payment 3x greater when images of eyes added and they were being ‘watched’
what is the overall conclusion about reciprocity?
Current evidence suggests reciprocity is not
widely important except in humans (although some authors would disagree) - nevertheless the idea has been influential in directing research towards mechanisms of stabalizing cooperative interactions and preventing defection, most notably the potential effects of punishment and reputation
