Lecture 8 (Altruism) - Slides Flashcards
1
Q
Altruism
A
- Action whose average effect is to benefit someone else at some cost to the actor.
- Both costs and benefits measured in expected fitness
- Altruism among non-kin can occur through:
1) Reciprocity
2) Costly Signalling
2
Q
Reciprocity
A
- Altruism among non-kin
- Can be direct or indirect
1) Direct Reciprocity: Preferentially help those who have provided help in return.
- Video: Blood meals in vampire bats. Bats who refuse to give a neighbor a blood meal, receive less in return. Reciprocal altruism in non-related organisms by proximity
- Linguistic evidence: Many phrases that represent this idea (tit for tat, quid pro quo, etc…
- Prisoner’s Dilemma, Tit for Tat, Emotional regulation
- Common Pool Resources: Does not explain cooperation in the context of common/public goods (see slide)
2) Indirect Reciprocity: Altruistic acts that are unlikely to be directly reciprocated, but may be rewarded via reputational effects. People like those who are altruistic, even to others.
- 2nd order punishment, game, costly signalling (hunting and hunter-gatherers), eyes, charity
3
Q
Prisoner’s Dilemma
A
- Pay-off matrix and game
- Illustrates how direct reciprocity sustains cooperation
- Both cooperate = 1 year of prison each, one defects:one cooperates 10:0, Both defect = 5 each
- Player A should defect, but so should B
- When both defect they get a worst payoff, so in the long run (multiple games with the same individual) it pays off to cooperate
- Because you don’t want your defection to come and bit you later and also it sustains cooperation longer
4
Q
Tit for Tat
3 keys and what it can be called
A
- Can also be called direct reciprocity
1) Never be the first to defect
2) Retaliate only after the other has defected
3) Resume cooperation when the other does
5
Q
Emotional Regulation
A
- How reciprocity is sustained
- Cooperation is regulated by emotions and our feelings about others:
Emotions that influence reciprocity include: Friendship/emotions of liking and disliking - Moralistic aggression
- Gratitude & sympathy
- Guilt
- Trust & suspicion
6
Q
Problem with Reciprocity
A
- Reciprocity doesn’t usually happen simultaneously, so we have to hold information of individuals who we know owe us and who we might owe
- This can lead to cheating
- Cheating can be advantageous in a population with lots of cooperators
- Cheater detection necessary for evolution of altruism in non-kin
- Oda et al. 2009, Barclay 2008
7
Q
Oda et al. 2009
Can we detect altruists?
A
- Males asked how often they performed altruistic acts
- The 7 highest/lowest scorers were video taped and sound was removed.
- Used questions which had the greatest difference in response used to determine altruism
- Another group took the altruism survey and watched the videos and rated how altruistic the video participants were
- Results: High altruists gave higher altruist scores to videos. Altruists were ranked as more altruistic that non-altruists
- Altruists were judged as more socially active, generous, responsible, friendlier and kinder
- But NO difference in: discreetness, hurriedness, and intelligence. Intelligence is important because it shows it’s not a halo effect.
8
Q
Barclay 2008
Can we detect cheaters?
A
- Trust game: P1 can not trust P2 and give $10 to each participant, or trust and P2 will share a $30 pot equally.
- P2 is computer with photo
- P2 either: 1) cooperate which gives $15 each, or defect which gives P2 20 and P1 5
- Encoding phase: 40 random opponents, did not repeat the same opponent and defection rate of opponents varied by 20/50/80%
- Distractor task: 10 minute demograhpic survey
- Recall phase: Unexpected facial recognition task (40 previous faces, 40 new faces), asked to classify as: Novel/Recognize and Cooperator/Defector
Results: When defectors are rare (20%), they are recalled more accurately than are competitors. Effect reverses when cooperators are rare.
- Suggests that when a strategy is rare, we are more likely to remember those who employ that strategy. We remember rare more.
- Because: Whatever behaviour is more common, it’s likely to represent the social norm (reduces cognitive load since you have to remember more)
- When defectors = 50%, our memory for cooperators has an advantage. Could be a bias towards seeking cooperators, but most people cooperate more anyways.
- From brief silent video clips, we can identify unknown altruists at rates higher than chance
9
Q
Common Pool / Public Goods
A
- A resources that gets depleted with each use and used by a large group of people
- No direct reciprocity possible: use you are not helping in return or expecting to help in return.
- About how you -allocate- those common goods
- Invite cheaters
- Tragedy of the commons
- Economic rationality vs. enlightened self-interest
10
Q
Tragedy of the Commons:
A
- Common ground where livestock can graze and each herder can bring some, but not all livestock
- The more you use it the more it’s depleted and the damage is shared by the group
- Economically rational: graze without regard of what is left over
- Enlightening self-interest: by limiting your own profits, you are helping yourself. Because if you all graze at once, it precludes your ability to graze in the future.
- Those who pay are “suckers”/tragedy of commons, so its in the cooperators best interest to develop ways to detect cheating.
11
Q
Tragedy of the Commons in the Lab
Game, 2 effects and manipulations
A
- Groups of 4 subjects play a game where they receive $20 to keep or donate to the common pool.
- Donations doubled the pot and were equally distributed among players.
- Example: If all donate $20, pool = 80*2 = 160, Each get 40
- But if 1 free-rides, Pool = 60*2 = 120, each get $30 but 1 gets 30+20=50
- Reputation, Punishment effect manipulations (see slides)
proximate mechanism (emotions). - Results: Most donate most of their money %50
- Donations fall over successive rounds, especially final round when end-game is known.
12
Q
Reputation Effect
and game
A
- Commons game manipulation
- Reputation Effect: manipulated anonymity and reputation (one group was anonymous, one met their group and were told their results would be told to the others later.
- Participants gave in non-anonymous/reputation manipulation
13
Q
Punishment Effect
game and order
A
- Punishment Effect: After each round participants could pay 1 to reduce payout to other player by 3.
- Free riders will never punish or cooperate because both are costly, without benefit
- Free rider punishment is altruistic because it will never benefit the punisher, only future players who play them
- 6 rounds, different players, anonymous (no reputation/reciprocity effects)
- Results: 84% punish at least once, 74% were imposed on free riders by cooperators
- Punishment was harsh, group spent on average, $10. - The less contributed/cheated, the greater the punishment (reflective of our criminal justice system)
- Punishment created more cooperators and no dip at the end of rounds
- Without punishment there was reduced cooperation and a decline to later rounds.
14
Q
Proximate mechanisms for cooperation & punishment
A
- Emotion
- Experiment: Scenario where a school project member contributes significantly less to the project, how angry would you be? (1-7). 84% > 5.
- Free-riding makes people angry and the exclusion of a social group may maintain cooperative behaviour.
15
Q
2nd Order punishment
A
- Costly punishment maintains contributions to public good and without it, contributions decline over time.
- Problem: Temptation to let others punish while keeping your share (2nd order). Do we punish non-punishers?
- Experiment: the more they contribute collectively, the more they get in return shares, they see how much every player gives, and are allowed to punish. 50% punish, in the next round, only 2% punish. No 2nd order punishment effect.
