Kinship Cues as a Basis for Cooperation in Groups: The Familiarity Hypothesis Mark Van Vugt University of Southampton With Mark Schaller & Justin Park, University of British Columbia

"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 other tribes, and this would be natural selection." -- Charles Darwin, The Descent of Man, 1871

Social Psychological Research on Prosocial Behaviour Lack of integration –few cross references between research on, for example, bystander intervention, volunteering, social dilemmas, organizational citizenship Narrow focus on proximate, psychological processes, such as: –Mood and helping –Empathy –Social identity –Attributions of responsibility

Evolutionary Roots of Cooperation Humans are social animals Capacity to cooperate – joint activities to produce mutual benefits For much of our history, we lived in small, largely kin-based tribal groups Group life produced many benefits (e.g., parental investment, group defense, food sharing) But, it also came with costs (e.g., conflict, free riders, coordination problems) Humans are conditional cooperators

Theories of Cooperation (1) Kin selection: individuals help their offspring and other kin because they share genetic information (inclusive fitness; Hamilton, 1964); (2) Reciprocal altruism: individuals help if they can expect something in return (dyad: direct reciprocity; group: indirect reciprocity); (3) Group selection: Individuals help others for the “good of the group” (see Darwin’s quote)

Kinship and Altruism (Smith et al., 1987)

Kinship Cues: The Familiarity Hypothesis Evolutionary pressures pertaining to kin selection require the emergence of mechanisms that allow the identification of kin (Krebs, 1987) No evidence for genetic similarity hypothesis (“green beard” mechanism, Dawkins, 1976) Rely on indirect cues that indicate familiarity – these cues are fallible

Heuristic Kinship Cues Empathy: ability to put oneself in other’s shoes (Batson, 1987) Proximity: decreases psychological distance and enhances aid giving (community identification and helping in a water shortage; Van Vugt, 2001) Similarity

Similarity Physical appearance (phenotype matching; Krebs, 1987) – similarity in facial features – similarity in race increases helping (Gaertner & Dovidio, 1977)

Similarity Shared norms, values, attitudes: – some attitudes are heritable (Tesser, 1993) – attitude similarity increases liking (Byrne, 1971) – attitude similarity increases empathy (Batson et al., 1981) – attitude similarity increases cooperation in social dilemma (Van Vugt & Hart, 2003)

High empathy increases helping regardless of costs (Batson et al., 1981) % of contributors High empathy increases helping regardless of costs (Batson et al., 1981) % of contributors

The Step-level Public Good Did at least four group members invest? NoYes ________________________________ Did you Invest?No£2 £2 + £4 (free rider) Yes 0 (sucker) £4 _________________________

Members of “similar” groups are more loyal to their group (Van Vugt, Schaller, & Parks, 2003) % of exits Members of “similar” groups are more loyal to their group (Van Vugt, Schaller, & Parks, 2003) % of exits

Similarity Group membership: –Ingroup favouritism in resource allocations (Brewer, 1979; Tajfel, 1971; Yamagishi, 1999) –Group identification increases ingroup cooperation (De Cremer & Van Vugt, 1999; Kramer & Brewer, 1984) –Group identification promotes loyalty to group (Van Vugt & Hart, 2003) – out of genuine concern for group –Supporters of same team come to each other’s aid (Platow et al., 1999)

High group identifiers contribute more to a public good than low group identifiers, (De Cremer & Van Vugt, EJSP, 1999) % of contributors High group identifiers contribute more to a public good than low group identifiers, (De Cremer & Van Vugt, EJSP, 1999) % of contributors

High group identifiers contribute more regardless of their social value orientataion (De Cremer & Van Vugt, 1999) % of contributors High group identifiers contribute more regardless of their social value orientataion (De Cremer & Van Vugt, 1999) % of contributors

High group identifiers are more loyal to their group than low group identifiers, (Van Vugt & Hart, 2003) % of exit High group identifiers are more loyal to their group than low group identifiers, (Van Vugt & Hart, 2003) % of exit

High group identifiers are more loyal regardless of their trust in others (Van Vugt & Hart, 2003) % of exit High group identifiers are more loyal regardless of their trust in others (Van Vugt & Hart, 2003) % of exit

Implications of Familiarity Hypothesis Connects diverse research lines on social psychology of prosocial behaviour Generates novel hypotheses about roots of cooperation –Smell as similarity cue??? Automaticity of prosocial behaviour –Empathy often leads to “mindless” helping (Batson et al., 1997)

Further implications Culture as mediator and moderator: –cultural norms promote helping kin –In Japan perhaps more kin-based cooperation and less cooperation with strangers (Yamagishi’s work) Individual differences in cooperation: –Prosocial value orientations may include more people in their empathy circle (De Cremer & Van Vugt, 1999) Disentangling kinship from reciprocity: –investigate the mediators: Trust or empathy?

Practical Implications Manipulating kinship labels to create familiarity –“brothers and sisters” “godfather” Adoption: –proximity cues at odds with similarity cues How to promote cooperation in larger groups? –stressing similarity between helper and receiver (speak same dialect, Dunbar, 2003; support same team; Platow et al., 1999) –Importance of between group friendships (similarity cues may be in conflict with each other)