Aggression between groups Session 8

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Aggression between groups Session 8

• SP603

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Exercise Which movies do you like best?

• Action Adventure
• Comedy
• Drama
• Romantic
• Science Fiction
• War
• Westerns
• Please rank from 1 (like best) to 7 (like least)

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Questions

• What are the origins of intergroup conflict in
  humans?
• Is there any evidence in the social psychological
  literature for an evolved intergroup psychology?
• How can intergroup relations in society be
  improved?

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Exercise

• You are a member of the Blue/Red team. You have
  10 to divide. How much do you give to a member
  of the Blue team and the Red team?

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• A tribe including many members who, from
  possessing in high degree the spirit of
  patriotism, fidelity, obedience, courage and
  sympathy, were always ready to aid one another,
  and to sacrifice themselves for the common good,
  would be victorious over most tribes and this
  would be natural selection
• -- Charles Darwin, The Descent of Man (1871)

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Evolutionary analysis of intergroup psychology

• Group living has given rise to adaptations for
• Aggression, harming others at personal gain
  (Buss, 1999)
• Altruism, helping others at personal cost (Van
  Vugt Van Lange, 2006)
• For early humans, there was an increased threat
  from rival groups (Alexander, 1987)
• Intergroup conflict selected for
• within group cooperation (altruism) for the
  purpose of achieving between group victory
  (Alexander, 1979 DeWaal, 1996 Tooby Cosmides,
  1988)
• Within group altruism is promoted and
  aggression is suppressed (ingroup morality)
• Between group altruism is suppressed and
  aggression is promoted (outgroup morality)
• The likely outcome of these selection pressures
  is unique evolved intergroup psychology among
  humans

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s
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How might intergroup psychology have evolved?

• Individual selection aggression towards
  outgroup members might benefit individual
  directly
• because they threaten you personally
• because you get status and esteem in your
  ingroup (indirect reciprocity costly
  signalling) among Yanomano, warriors have
  greater status and multiple sexual partners
  (Chagnon, 1997)
• But then how do you explain that people sometimes
  are willing to give their lives to defend their
  group?
• Through kin selection (Hamilton, 1964)
• helping ingroup member (relative) by harming
  outgroup member (non-relative) might pay off,
  according to Hamiltons rule (suicide attacks)
• Through group or multilevel selection (Wilson,
  1994 2002)
• For men, likely to be stronger selection for
  intergroup aggression than for women, this is
  known as the male soldier hypothesis (van Vugt et
  al.),
• But why?

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Multilevel selection theory (Wilson, 2002)

• Any biological system is a hierarchy of units
• Genes reside within individuals, which reside
  within groups, which reside in metapopulations
• At every level (genes, individuals, groups)
  natural selection can occur in theory
• When natural selection operates at a given level,
  it promotes traits that increase the relative
  fitness of units at that level (but these traits
  may be maladaptive at a different level)
• For example, the gene that cooperates with other
  genes sacrifices itself for the sake of the
  organism
• For example, cheaters do well in terms of
  individual fitness, but groups with many cheaters
  do bad at the level of the group

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Multilevel selection as pathway to intergroup
behaviour

• Behaviours that favour ones group but are not
  costly to oneself can evolve without any problem
  for example, conformity
• What about group behaviour that are personally
  costly, like defending your group?
• This is open to the cheater problem
• selfish individuals (those that do not defend
  their group) may produce more offspring than
  altruists (who help to defend their group), but
  groups with more altruists might produce more
  offspring than groups with fewer altruists, so
  the total number of altruists may remain stable
  in a population
• For this to be the case there must be serious
  intergroup level competition, and groups must
  also periodically go extinct or reform (in order
  to prevent non-altruists from taking over the
  group)
• Does this theory apply to humans??????? That is
  the 1million question!

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Social psychological theories of intergroup
conflict

• Realistic conflict theory (Campbell, 1965)
  integroup conflict is caused by competition among
  groups over limited resources (e.g., food,
  territory)
• Social identity theory (Tajfel Turner, 1976)
  categorization (between us vs. them) is a
  sufficient cause of conflict
• An evolutionary perspective can easily integrate
  these theories

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The social psychological literature
Predictions based on evolved intergroup
hypothesis

• Intergroup conflict is common in humans (now and
  certainly in the past)
• Coalitions between people should be relatively
  flexible i.e., groups should frequently
  experience change (disband, reform)
• People should be able to quickly identify with a
  group
• They should have a capacity to form deep
  emotional attachments to groups
• People should prefer to harm outgroup members
  over ingroup members
• People should prefer to help ingroup over
  outgroup members
• People should be willing help their ingroup
  without necessarily expecting a direct return
  (multilevel selection does not require individual
  benefits, but group benefits)
• People should be willing to harm those who
  threaten the ingroup without expecting a return
• Men are more likely to engage in intergroup
  aggression than women (male soldier hypothesis)

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Exercise

• Recall last monthss interactions that you had
  with other people how many aggressive
  interactions (conflicts, threats, physical
  aggression) did you have?
• How many of these were
• One-on-one
• Within group
• Group-on-group

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1. There should be frequent examples of
intergroup competition among humans, now and in
the past

• War is an exclusively human activity (Buss, 1999
  Tooby Cosmides, 1988)
• Our closest genetic relative, the chimpanzee, do
  it as well (Boehm, 1999 De Waal, 1996 Wrangham
  Peterson, 1996) especially males
• Competition between groups is common in modern
  society, in sports, businesses, universities,
• People are more competitive in intergroup than
  interindividual situations
• When researchers examined every day social
  activities, they found that group-on-group
  interactions are more competitive than one-on-one
  activities (Pemberton, Insko Schopler, 1996)
• Intergroup relations are more competitive than
  interpersonal relations in Prisoners Dilemma
  Games (Insko, Schopler, 1998)

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The Prisoners dilemma
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2. Coalitions between people should be
relatively flexible i.e., groups should
frequently experience change (disband, reform)

• Group fissions and schisms are quite common (Hart
  Van Vugt, 2006)
• Groups also regularly go extinct and reform
  (religious cults, Sosis Wilson, 2002 New Guinea
  tribes Boyd Richerson, 2002)

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3. People are able to quickly identify with a
group

• Minimal group paradigm research (Brewer, 1979)
  shows that participants give more money to
  ingroup than outgroup members, even if group
  membership is based on trivial criterion (like
  art preference or flip of coin) Tajfel Turner,
  1986)
• Allocation into different groups undermines
  existing friendships (Sherif et al., 1961
  Robbers cave experiments)

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4. Individuals should be capable of forming deep
emotional attachments to groups

• Ingroup members are loyal to their group, even
  when loyalty is quite costly (Van Vugt Hart,
  2004)
• Friendships are more likely to form within groups
  than between groups
• Employees who identify with their organization
  are more likely to stay (Abrams et al., 1986)
• Some fans do not sleep after their favourite team
  has lost
• Or, the get a heart attack while watching a
  football game on TV (Lancet)
• People are sometimes prepared to die for their
  country (Keegan, 1994) religion, or other cause
  (Atran, 2002)

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5. Group members should want to harm outgroup
members more than ingroup members

• How would you test this idea in an experiment?

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5. Group members should want to harm outgroup
members more than ingroup members

• Minimal group research
• Ingroup members think all outgroup members are
  untrustworthy and they are alike (outgroup
  homogeneity effect Judd Park, 1988)
• They also derogate outgroups (Doosje et al.,
  1998)
• They feel Schadenfreude when a rival group loses
  (Leach et al., 2002)
• Group members tend to make sweeping statements
  about an entire outgroup (stereotyping Quattrone
  Jones, 1980)
• Ingroup members morally justify aggressive
  actions against outgroup members (Yamagishi,
  2002)
• Ingroup members dehumanize outgroup members
  (Leyens, Yzerbyt et al.) , which may be regarded
  as a precursor of outgroup aggression (genocide)

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6. Group members should prefer to help ingroup
over outgroup members

• Minimal group paradigm research
• Even selfish people show altruism towards their
  ingroup in an integroup competition (De Cremer
  Van Vugt, 1999)
• People cooperate more when an ingroup identity is
  made salient (Brewer Kramer, 1986)

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7. Group members should willingly engage in
helping the group without necessarily expecting a
return

• Group identification is not mediated by feelings
  of trust or reciprocity (Brewer, 1991 De Cremer
  Van Vugt, 1999)

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8. Group members should willingly engage in
harming individuals that threaten to harm the
group without expecting a return

• People readily sign up as soldiers when their
  country is in war (Stern, 1995)
• Suicide bombers do not expect a return (at least
  not during their lives)
• Group members readily punish ingroup members that
  are selfish (Fehr Fischbacher, 2003) or
  disloyal to the group (Van Vugt Chang, 2005)
• Research on black sheep effect (Marques, Leyens,
  Yzerbyt)
• Research on scapegoating and mob lynching

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9. The male soldier hypothesis Mens psychology
is more strongly affected by intergroup threat
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What Can Be Done About Intergroup Conflict?

• Break down the barriers between groups
• Intergroup Contact (Allport, 1954)
• Encounters between members of different groups
• Cooperative goals
• Same status individuals
• Institutional support
• Successful team performance
• School integration
• Friendships
• Multiracial marriages
• Cognitive cures Decategorization,
  recategorization, cross-categorization how
  effective are they?
• Perhaps focus on men in particular?

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Take-home message

• Human history is characterized by intergroup
  competition
• As a consequence, humans have an evolved
  intergroup psychology, which enables them to form
  attachments to ingroups (of kin and nonkin), and
  discriminate against outgroups
• The social psychology literature provides a lot
  of evidence for a domain-specific evolved
  intergroup psychology
• Evolutionary thinking suggests that intergroup
  conflict is more likely to emerge if there is
  competition between groups (for resources or
  prestige) it is thus in line with both social
  identity (Tajfel), and realistic group conflict
  (Campbell) accounts of intergroup behavior.

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Evolutionary psychology and warfare (risk
contract of war hypothesis Tooby Cosmides,
1988)

• The average long-term gain in reproductive
  resource must be sufficiently large to outweigh
  the reproductive costs of engaging in warfare
  over evolutionary time
• Members of coalitions must believe their group
  will emerge victorious
• The risk that each member takes and the
  importance of each members contribution to the
  success must translate into a corresponding share
  of benefits
• People who go into battle must be cloaked into a
  veil of ignorance about who will live or die

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Predictions from warfare hypothesis

• Men but not women will have evolved psychological
  mechanisms designed for warfare
• Sexual access to women ill be the primary benefit
  for men
• Men should have evolved psychological mechanisms
  to panic or defect in the face of death
• Men should be more likely to go to war when the
  odds of success are better
• Men should have evolved psychological mechanisms
  to enforce risk contract
• Men should have evolved psychological mechanisms
• designed to detect, prefer and enlist men in the
  coalition who are willing to and able to
  contribute to its success.