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Reciprocal Altruism and Group Behavior

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					Reciprocal Altruism and
Group Behavior

  By Alejandra Fernandez-Ortega
    Reciprocal Altruism
   Beneficial acts to non-relatives that are
    later repaid by the beneficiary
   Prerequisites:
       Cost of the altruistic act must be lower than
        the benefit to the actor
       Animals must be capable of recognizing
        each other in order to reciprocate and
        detect cheats
       Must have reasonably long lifespan in
        order to re-encounter individuals and to
        have the chance for reciprocation to occur
   Unlike kin selection, rare in animal
    kingdom
Examples of Reciprocal
Altruism in Animal Kingdom
   Olive baboons
   Vampire bats
   Green woos hoopoe
   Dolphins
   Vervet monkey
Examples of Reciprocity in
Pre-Industrial Societies
   !Kung San of South Africa            Yanomamo of South
                                          America
   Small, nomadic bands of
    hunter-gatherers                     Small, permanent villages
                                          and slash-burn agriculture
   Gift economy-all meat
    shared equally across tribe,         Division of labor, economic
    with expected reciprocity             specialization and trade
                                          economy
   Hoarding meat or boasting
    about hunting skill is cultural      Reciprocity more limited,
    taboo                                 wealth accumulated and not
                                          equally divided
   Makes evolutionary sense
    within nomadic hunter gather
    society
   Extremely high murder rate
Game Theory and the
Prisoner’s Dilemma
   Game Theory: finding the best possible solution to a
    problem taking into account what everyone else does
   Prisoner’s dilemma: the optimal outcome for a group
    is achieved only when each individual cooperates, or
    makes a decision that would not be in his individual
    best interests
   R=mutual reward for cooperation, T=temptation to
    defect, P=Punishment for mutual defection,
    S=sucker’s payoff
    T>R>P>S
     Iterated Prisoner’s Dilemma
     and Reciprocal Altruism
   In a single occurring prisoners
    dilemma, logical choice is to defect
   However, in re-occurring social
    situations, people fall into patterns
    of mutual cooperation because they
    each know that if they cooperate
    they can expect future cooperation
    in the form of reciprocity and if they
    defect, they can expect retaliation in
    the future
   Tit-for-tat
        Nice
        Retaliatory
        Forgiving
Indirect Reciprocation
   Critique of reciprocal altruism
    theory-people commit acts of
    altruism that cannot hope to be
    repaid directly by the
    beneficiary
   E.g. blood drive
   Indirect reciprocation-
    demonstrating cooperation and
    selflessness makes others more
    likely to cooperate in the future
        Reputation and social worth
   Karma?
    Study of Individual Differences in
    Reciprocity Styles
    (Houser & Kurzban, 2004)

   Subjects randomly assigned to a series of 4-
    person groups for at least 7 games
   Could invest tokens into private accounts or
    pool into a public account to be doubled and
    shared (Prisoner’s Dilemma)
   Each participant in turn given at least one
    chance to change allocation based on current
    total contribution to public account
Results
   Cooperation strategies proved stable across games
   Cooperators (13%)-contributed a great deal most of the
    time, regardless of overall group contribution (~50 tokens)
   Free riders (20%)-contributed almost nothing most of the
    time, regardless of overall group contribution (~1 token)
   Reciprocators (63%)-based their contributions on how much
    others in each game contributed (~25 tokens)-
   No statistical difference in individual earnings between types
   Group composition predicted future cooperation levels
    Implications
   In any given population there are stable,
    distinct, and co-existing cooperative
    strategies that predict reciprocal altruism
       Cooperators-contribute to group welfare at cost to
        self
        Free riders-do not contribute, no cost to self
       Reciprocators-conditional strategy
   High levels of free riders reciprocators in a
    population predict a break down in group
    cooperation and reciprocity.
Personality Traits and Social Cognitive
Beliefs Predicting Altruistic Styles
(Alessandri et. al., 2009)
      Study:
          377 adolescents
          Completed measurement scales measuring trait agreeableness, social
           cognitive self evaluations and prosociality at ages 16 and 18
      Findings and implications:
          Agreeableness personality trait and empathic self efficacy beliefs were
           correlated with degree of cooperation and self sacrificing altruistic
           behaviors.
          High degree of heritability for agreeableness implies that individual
           differences in altruistic behavior are largely heritable
          Changes in agreeableness and empathic self efficacy across time
           predicted similar changes in altruistic and other prosocial behaviors
          In general, females score higher on agreeableness, empathic self
           efficacy, and altruistic prosocial behaviors compared to males
          Agreeableness as a broad personality trait may have evolved as a
           general mechanism for direct and indirect social reciprocity
Social Cognition and the Development
of Reciprocal Altruism
(Barret & Tooby, 2010)

   While many animals have kin selection, very few
    species have reciprocal altruism
   Hypothesis: for reciprocal altruism to be effective,
    must have theory of mind necessary to predict
    the intents of others, to maximize reciprocal gain
    and minimize free riding losses
   Humans have evolved special cheater detection
    mechanisms to predict the intents of humans
    which help us make decisions about whether or
    not to reciprocate
   Study:
       “Benefit” condition
            Hypothesis: people should be able to predict whether or not
             someone has an incentive to “cheat” or free ride based on whether
             or not they would benefit

            Finding: Research subjects increased their vigilance for cheating
             by 20% when they believed that the person’s kin would gain by
             free loading behavior
       “Ability” condition
            Hypothesis: people should be more wary of potential cheating and
             dishonesty if they believe that the other person has the opportunity
             to free ride
            Finding: if potential cheaters lost the opportunity to cheat due to
             lack of knowledge, vigilance decreased by 20%
       “Intent” condition
            Hypothesis: People should be more wary of free loaders if they
             know the subject has the intent to cheat
            Subjects cued to possibility of intentional or accidental rule
             breaking; vigilance increased dramatically during “intent”
             condition but not “accidental” condition
Study Conclusion:
   Reciprocal altruism is an effective strategy for
    humans because we have evolved an
    advanced theory of mind and the necessary
    social cognitive strategies to root out and
    exclude free riders
   Reciprocal altruism is rare in the animal
    kingdom because most animals lack the
    necessary theory of mind to successfully
    prevent free riding

				
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posted:8/28/2011
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