1. Evolutionary Psychology, Workshop 3: Altruism and Cooperation.

2. Aims of the Workshop. z1. Review the Burnstein et al., (1994) study on helping behaviour. z2. Collate and interpret results from the 'who shall I save/help?' tasks in light of the Burnstein et al., (1994) report. z3. Observe a demonstration of 'prisoner's dilemma' to assess cooperative and competitive behaviours and discuss the outcomes. z4. Watch a clip from the TV series 'Shafted' and discuss the behaviour of the contestants in the context of the 'prisoner's dilemma'.

3. Background. zBurnstein et al., (1994) pointed out that during natural disasters people's uppermost concern is with their families. zThe idea that concern for others should be dependent upon relatedness has been predicted by evolutionary biologists in their discussions of 'inclusive fitness’. zBurnstein et al., (1994) argued that social psychologists could perhaps take into account inclusive fitness as it may provide explanations for certain human social behaviours involving cooperation, exchange, competition and attraction.

4. Hypotheses. zA key hypothesis to be addressed in this session is that natural selection may favour a tendency to discriminate amongst others who require help according to their degree of relatedness. zPeople should be able to weigh up the costs/benefits of the outcomes of certain social situations, especially those situations involving a decision as to whether to help someone or not. zWe are very interested in who is related to who, who is having a relationship with who as such information may well influence our behaviour to that person.

5. Burnstein et al., (1994) Study. zThey argued that our decisions to help or assist another individual should be influenced by the perceived degree of relatedness we share with an individual. zFor example we should be more likely to assist another when they are close relatives (e.g. a sister) than when they are more distantly related (e.g. a cousin) or indeed if they are unrelated. zOther factors may also contribute to this decision making process. zFor example age, sex, wealth, and health can influence inclusive fitness.

6. Decision Rules for Altruism. zBurnstein et al., (1994) presented 158 American and Japanese undergraduates with a series of social dilemmas in which the person had to rank-order individuals differing in their degree of relatedness in terms of help or assistance. zThey found the following:

7. Tendency to help kin under life or death versus everyday situations.

8. Tendency to help as a function of age, under life or death versus everyday situations.

9. Tendency to help as a function of sex and age, under life or death conditions.

10. Tendency to help as a function of sex and age, under everyday conditions.

11. Tendency to help as a function of health under life or death or everyday conditions.

12. The Task. zYou have 4 sheets, each with two versions of the 'who shall I save/help' task. zTest 4 participants and record their ratings in the spaces provided. zIn the data record insert the raw data and calculate the mean rankings. zWe can then draw a graph of the group data which plots mean help ranking against degree of relatedness:

13. Our Data.

14. ‘Prisoner’s Dilemma’ Demonstration. zThe aim is to win as many points as you can against your opponent. zOn each trial you have to hold up one of the markers. zIf both of you hold up a blue marker you each win 3 points. zIf both hold up a red marker you each win 1 point. zIf one holds up a blue marker but the other holds up a red marker, the the blue marker holder wins nothing, but the red marker holder wins 5 points. zYou cannot speak during the game. The judge will announce each person's choice of marker after you have both made your choices, and they will tell you how many points you have each won.

15. Prisoner’s Dilemma Payoff Matrix

16. Increased Co-operation in Twins. zIn light of kin selection theories we may expect that in such encounters, people who are related to one another may be more likely to cooperate than unrelated individuals. zSegal & Hershberger (1999) tested the hypothesis that higher levels of co-operation would be associated with increased genetic relatedness. z59 MZ twins and 37 DZ pairs played ‘Prisoner’s Dilemma’ in which each was encouraged to win as much money as possible at the expense of the other. zThe game was played for 100 trials (participants were not told this) and earnings were continually announced. zThe number of points collectively earned by MZ twins significantly exceeded those won by DZ twins, and the MZ twins displayed significantly more co-operative acts that increased over time.

17. References. zBurnstein, E., Crandell, C., & Kitayama, S. (1994). Some neo- darwinian decision rules for altruism: weighing cues for inclusive fitness as a function of the biological importance of the decision. Journal of Personality and Social Psychology, 67: 773-789. zSegal, N.L., & Hershberger, S.L. (1999). Cooperation and competition between twins: findings from a Prisoner’s Dilemma game. Evolution and Human Behaviour, 20: 29-51.