The Problem of Altruism toward Nonkin Evolutionary Psychology

The Problem of Altruism toward Nonkin Evolutionary Psychology Spring 2020 Dr Chapman 1

The Evolution of Cooperation Many examples of helping nonrelatives o o Expressed cross-culturally including hunter-gatherer societies i. e. it is universal Inclusive Fitness “Kin Altruism” can not explain helping nonrelatives Sharing food Donating to charity Rescuing unrelated individuals Sacrificing for moral or ideological principles How could altruism toward nonkin evolve? Cooperation in nonhuman animals Forms of this social behavior evolved long before humans So it does not require complex human culture !! Such as concepts of morality and religion 2

Theory of Reciprocal Altruism Typically this is cooperation between two or more individuals for mutual benefit across time so it consists of a series of interactions Also called: direct reciprocity, cooperation, reciprocation, or social exchange Example: "food sharing" o o o hunter-gatherers probability of successful hunting -- 1/30 6 males per village meat lasts village 5 days cost of sharing small (due to spoilage) benefit of sharing is large Gain in trade or sometimes called “Gain from trade": benefit is greater then cost for both parties Because the benefits outweigh the cost individuals who engage in reciprocal altruism will have higher levels of survival and be able to out reproduce individuals who do not engage in reciprocal altruism the problem of cheating reduces the benefits from reciprocal altruism will come back to this as a separate issue later in this topic 3

Cooperation Among Nonhuman Animals Vampire Bats o o o share food but not indiscriminately: share with those from whom food was received increased propensity with: close association defined as: in proximity at least 60 percent of time more likely to share when need for food was greater Principles of Reciprocal Altruism expressed in Bat behavior: o o o frequent contact for long periods frequency of association correlated with degree of altruism over time benefits to giver higher than costs to giver frequent reversal of circumstances preference given to those who have recently helped 4

Reciprocity in Non-Human Primates Baboons o o o solicit help during conflict: rapidly shift eyes between recruit and antagonist greater response to requests in sexual conflicts results in successful mating 80 percent of time responder does not benefit directly, sexually enhances likelihood of future reciprocal response sexual success rare in absence of male friendships Recordings of Female Vervet monkeys vocal solicitations for help o o o attentive response more likely from those who had been groomed recently by the solicitor grooming only enhances response to non-kin reciprocal altruism rather than kinship 5

Political Alliances in Primates "Chimpanzee Politics" Male chimpanzees fight for social hierarchy “dominance” in the group Male political alliance with other males necessary to move up social hierarchy Help when fighting for dominance Maintain these relationships with grooming and food sharing More on this in the next chapter on Aggression Male chimpanzee status also depends upon reciprocal alliances with females Defend female against attack Regularly solicit alliances with females o groom females o play with their infants 6

Cooperation and Altruism Among Humans • Development of Reciprocity The Development of Contingent Reciprocity in Children. House(2013) During play; 3– 5 year-old children provide help and give objects (e. g. toys) to peers whom had acted prosocially towards them o more likely to reciprocate with others whom gave them something o seems to be moderated by the intention of the other child, did they do it spontaneously or where they instructed to do so Overall children reciprocated contingently on 63% of trials, mostly seen in children older then 5. 5 years Not much evidence of contingent reciprocity in chimpanzees using food rewards 7

Cooperation and Altruism Among Humans Social Contract Theory Cheating Problem of reciprocal altruism: o o o Not simultaneous so there is a potential for cheating Cheaters would have an advantage such that: they would out breed non-cheaters/altruists altruism would disappear from genome unless psychological mechanisms evolve for detection and avoidance of cheaters Requirements For Social Contracts 1. Recognition of many individuals 2. Memory for interactions 3. Ability to Communicate one’s Values 4. Ability to model values of others 5. Ability to represent Costs and Benefits abstractly i. e. set value on a large variety of objects and behavior Abstractly, does not require math just subjective values i. e. “good---bad” 8

Social Contract Theory Evidence for cheater detection adaptations o Example 1: Wason Task Data: four cards with a b 2 3 on the front Rule: If a vowel on one side then an even number on other side Which card to turn over to test the rule? Test either a or 3 but not b or 2 Over 90 percent of college students failed to test rules correctly Example 2: with social context Rule: No drinking under 21 yrs. of age Data: four people around a table o Someone drinking beer Someone drinking soda A twenty five year old A sixteen year old Task: Whom do you check? 75 percent correctly checked sixteen year old someone drinking beer 9

Social Contract Theory Cheater Detection "do people remember cheaters? " o o Psychological mechanism to focus attention on rule breaking Specialized brain circuits Patient R. M. o Sensitive to perspective: attention to rule breaking based on relationships example: "If an employee gets a pension, he has worked for ten years. " o with normal risk assessment but poor understanding of social contracts susceptible to scams employee looks for "worked for ten years but no pension" employer looks for "got pension but did not work ten years" Better memory for faces of cheaters 10

The Detection of Prospective Altruists Problem of detecting genuine altruistic acts Why would someone give money to a homeless person or to a charity o o Honest signal of beliefs and feelings o see costly-signaling theory in the next topic Just trying to impress others o does not represent their true beliefs (dishonest) How can you tell the difference? Watch for helping behavior and seeking credit "humility detector" • Use the altruistic detection task which is similar to the Wason task • most people choose cards that allow them to detect genuine altruists – Facial expressions of genuine smiles • Trust your “gut feeling” i. e. emotional response o 11

Game Theory Approach John von Neumann and Oskar Morgenstern invented game theory using common parlor games such as poker and chess Chess is a zero-sum game: the gains of one player are the losses of another. Most real-life interactions are mixed-motive they display elements of cooperation as well as competition A number of experimental games have been used to study cooperation and competition in experimental economics. o o Prisoner's Dilemma Game Ultimatum Game Public Goods Game Dictator Game 12

Prisoner's Dilemma Game "tit for tat" The Evolution of Cooperation, Robert Axelrod and William D. Hamilton (1981) Setup: o o o two individuals accused of a crime that they are guilty of held in separate prison cells so that they can not communicate police interrogate both of them and try to get them to rat on the other person Rules: o o "cooperation" if both are silent then both go free "defection" if you rat out the other person, you go free and the other person is punished "mutual defection" if they both “rat-out” the other person then both are punished see figure 9. 1 13

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Prisoner's Dilemma Game "tit for tat" Use of computer programs to model game theory o o o Axelrod and Hamilton 1981 Computer tournament with competing strategies to win the prisoners dilemma game Some of the strategies tested in the tournament always defect alternate defect and cooperate "tit for tat" which is contingent reciprocity 1. cooperate on first play 2. reciprocate on every play thereafter If they cooperate then you cooperate If they defect then you defect Winner of the tournament 15

Prisoner's Dilemma Game "tit for tat" • To promote a cooperative society – Axelrod, 1984: Evolution of Cooperation – Enlarge the shadow of the future • Repeated interactions over time with no set end date – Teach reciprocity – Insist on no more than equity – Cultivate a personal reputation as a reciprocator Axelrod, 2012 Launching ‘‘The Evolution of Cooperation’’ o problem with original "tit for tat' o one’s action will not be perceived correctly by the other player o generous "tit for tat" is effective in dealing with misperception o o o Never be the first to defect Retaliate only after the other has defected Be forgiving 16

Prisoner's Dilemma Game "tit for tat" • Sigmund and Nowak – computer simulations of the dilemma using large communities • These are math models • a random distribution of defectors and cooperators • after each round of the game the winners would go on to produce offspring who would participate in the next round. • The offspring mostly followed their parents’ strategy, although random mutations could shift their strategy. – within just a few generations all the individuals in the population were defecting in every round of the game. – Then, after some time, a new strategy suddenly emerged: players would start by cooperating and then mirror their opponents’ moves, tit for tat. – The change quickly led to communities dominated by cooperators. – Within 20 generations the initial tit-for-tat strategy had given way to a more generous strategy in which players might still cooperate even if their rival defected. 17

Why We Help Martin A. Nowak • Selfless behavior is common in biology systems such as cells, ants, lions and humans. • Struggle for survival – Competition and cooperation both contribute to evolution of life on earth, from the first cells to Homo sapiens. – “Life is therefore not just a struggle for survival—it is also, one might say, a snuggle for survival. ” 18

Mechanisms for the Evolution of Cooperation • Evolution of Cooperation: on average the cost of altruistic behavior needs to be less then the benefits • 1. Kin selection based on Hamilton’s Rule: altruistic cost is lower than the benefit times degree of genetic relatedness on average • 2. Reciprocal altruism: (direct reciprocity) altruistic costs are offset when reciprocation returns benefits, because of gain in trade benefits will be larger then the costs • 3. Spatial selection: cooperators and defectors are not uniformly distributed in a population • Neighbors (or friends in a social network) tend to help one another, • 4. Indirect reciprocity: Very important in humans (next topic) • 5. Group Selection: Group membership: individuals that you identify as part of a coalition or "in-group" (next topic) 19

The Economics of Fair Play Karl Sigmund, Ernst Fehr, Martin A. Nowak • Ultimatum Game Setup and rules: o Given a sum of money equal to two days wages that you have to share with someone else. o The other player can either accept or reject your offer. o Both players know the total amount but can not talk to each other. o If your offer is rejected you both get nothing. o Usually played anonymously Industrialized societies have average offers of 40 to 50 percent with 40 to 60 percent rejection rate when offers are less then 20 percent 20

The Economics of Fair Play Homoeconomicus Research on cooperation indicates that humans o o o economic man, is the portrayal of humans as agents who are consistently rational and narrowly self-interested assumes that people selfishly seek to maximize their gains However, most people place a high value on fair outcomes So this is not a useful model of human economics are reciprocal altruists care about fair play are willing to reward cooperation and punish cheating Psychology of Fair Play: o why do we demand fair play? o think in terms of repeated encounters o important to be part of a group o others will notice our decisions, i. e. reputation 21

The Economics of Fair Play Cross-Cultural comparisons: What are the cultural influences on this cooperative behavior? o o o Cross-cultural Study of Cooperation in 15 small-scale societies (Henrich 2005) using ultimatum game Overall from 15 societies Average Offers vary from 26 to 58 percent Cultural influences there are cultural traditions in sharing and gift giving Ache and Achuar make offers around 50 percent and reject no offers reflects the culture of gift-giving which obligates the receiver to reciprocate lowest rates, 26%, found in the Machiguenga society related to widespread meat-sharing and cooperation in community projects Au and Gnau make offers greater than 50 percent with frequent rejections of these offers most people all over the world place a high value on fair outcomes strong obligations that result from accepting a gift little cooperation, exchange, or sharing beyond the family unit What Explains Group-Level Differences? o o How important and how large is a group’s payoff from cooperation in economic production How much do people rely on market exchange in their daily lives 22

The Economics of Fair Play Public Goods Game Similar to the scenario known as the Tragedy of the Commons investigate how people behave when individual and group interests conflict current problem of over fishing the oceans Rules: o o o four players in a group The experimenter gives each player $20 they have to decide how much to invest in a common pool the common pool is doubled and distributed equally among all four group members If every player contributes the full $20 they all double their capital cooperation is highly rewarding 23

The Economics of Fair Play o o Public Goods Game But the temptation to hold back on one’s own contribution is strong o many invest at least half of their capital o o you do not contribute to the pool so you are a free rider everyone else contributes you still get some of common pool after it is doubled But when the same group repeats the game for 10 rounds, toward the end, most group members invest nothing However, if a new rule is introduced o o "OK to punish other players at a cost to yourself" Players can give a fine to other players at the end of each round at a cost to themselves, for example $1. 00 fine with a cost of $0. 30. 24

The Economics of Fair Play Public Goods Game o When free riders are punished: fines are imposed on players whom do not contribute the full amount Contributions to the common pool rise over time, and in the last few rounds more than 80 percent of all group members invest the whole capital Even if, players are redistributed after every round, still have punishment of free riders and high level of investments interested in obtaining personal revenge pleasure in getting even with free riders "Altruistic Punishment" Use of punishment to keep cheating in check increases the level of cooperation o More on this in the next topic 25