PSY 544 Lecture Notes - Lecture 9: Ingroups And Outgroups, Caudate Nucleus, Nicotine
• Specialized cheater-punishment adaptations
• Shinada et al. (2004)
• Three traders
• One observer
• No direct reciprocity, in that giving goes only one way around.
• The selfish move is to keep all your money and hope you are gifted some by the
previous trader.
• The observer can, sometimes, choose to punish traders, by paying some of their own
money to deduct 3x that amount from a chosen trader.
•
• Specialized cheater-punishment adaptations
• Shinada et al. (2004)
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• Amounts deducted by observers were taken after all three rounds were played,
meaning they could not influence behaviour in any round (non-instrumental
punishment)
• You can either be a trader or observer, you play three rounds of the game, punishment
cant influence anyone's behv as it's punitive punishment
• In the first round, the real participants acted played as traders and gave an average
of 125.84 yen away (only 2 participants chose to gave nothing). They received all 200
yen from the trader.
•
• Specialized cheater-punishment adaptations
• Shinada et al. (2004)
• In the second round, participants gave an average of 147.02 yen. Increased the
amount they were willing to trade so they showed evidence of being effected by the
generosity of the trader before them
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• So some people (a little over half) gave all 200, having previously received 200 while
the rest who gave less than half of the amount they had to the next person
• 45 of 87 gave all 200 yen - these were labelled the cooperates
• 42 of 87 gave about half (90 yen) - these were labelled the non-cooperates
• They all again received 200 yen from the trader previous to them
• So, about half the participants showed evidence of indirect reciprocity (pay it
forward).
•
• Specialized cheater-punishment adaptations
• Shinada et al. (2004)
• In the third round, participants played the observer role and watched the other
participants/ or what they thought were other participants exchange money and
then the observer could use their money to punish any of the traders
• In one instance: on person gave up 200, the next gave up 180, next person only gave
up 50. they were told these three people were from the same uni/college as them so
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Document Summary
In the first round, the real participants acted played as traders and gave an average of 125. 84 yen away (only 2 participants chose to gave nothing). They received all 200 yen from the trader: specialized cheater-punishment adaptations, shinada et al. (2004) In the second round, participants gave an average of 147. 02 yen. In the third round, participants played the observer role and watched the other participants/ or what they thought were other participants exchange money and then the observer could use their money to punish any of the traders. Punishment of the in-group they also measured peoples responses to questions about: if you assigned punishment, why did you assign it. Punishment of the in-group (but not the out-group) member was motivated by (self-reported) anger and a sense of feeling of unfairness. Later replicated the results even when punishment was not tripled.
