Average 81 3 Median 82 9 Lecture 9 Psychology of Culture Are We Inherently Selfish or Altruistic Selfish B Altruistic C Who knows A Prisoners Dilemma Imagine 2 prisoners who have been picked up as suspects for a crime They are separated police offer each a reduced sentence if they will implicate the other their partner in the crime Payout Matrix Player B Cooperat e in years prison Cooperat e Player A Payout Matrix Player B Cooperat e in years prison Cooperat e Player A 1 Defect Payout Matrix Player B Cooperat e in years Defect prison Cooperat e Player A Defec t 1 5 Payout Matrix Player B Cooperat e in years Defect prison Cooperat e Player A 1 Defec t 0 5 Payout Matrix Player B Cooperat e in years Defect prison Cooperat e Player A 1 5 Defec t 0 3 Payout Matrix Player B Cooperat e in years Defect prison Cooperat e Player A Defec t 1 1 5 0 0 5 3 3 Payout Matrix Player B Cooperat e Rewards Cooperat e Player A Defec t Defect 3 3 0 5 5 0 1 1 Implications Therefore always defect is the evolutionary stable strategy ESS Resistant Might to invasion there be others Repeated Prisoner s Dilemma What if you new you were going to play many times Now you can use knowledge of previous plays to determine future strategy Tit for Tat Note that Tit for Tat is Nice always starts as a cooperator Retaliatory punishes non cooperators Forgiving goes back to cooperating if other player does Needs other tit for tatters or cooperators to do well Economic Games Dictator Game You are given 20 that is yours to keep You can give as much as you d like to another random participant How much do you give 0 B 5 C 10 D 15 E 20 A Economic Games Dictator Game Modes at 0 and 50 Around 2 3 give something Economic Games Dictator Game Ultimatum Game You are given 2 extra credit points You can give as many of those points as you want to the other half If they accept everyone gets the points as you allocated If they reject no one gets anything How much do you offer 0 B 0 5 C 1 0 D 1 5 E 2 0 A Ultimatum Offers in 13 Developed Countries Machiguenga vs Pittsburgh Ultimatum Offers in 15 Small scale Societies Ultimatum Offers in 15 Small scale Societies 15 Small scale Societies 13 Developed Countries Au of Papua New Guinea Lamalera of Indonesia External Validity Degree to which results can be generalized to other contexts Las Vegas Sample Las Vegas Sample Economic Games Dictator Game Ultimatum Game Trust Games Volunteer Games Volunteer Game If no one volunteers everyone receives 0 75 extra credit points If someone does volunteer they will receive 0 25 extra credit points while the others will receive 2 extra credit points A I volunteer Economic Games Dictator Game Ultimatum Game Trust Games Volunteer Games Rationality Wolf s dilemma Wolf s Dilemma If no one pushes the button everyone receives 3 extra credit points If anyone pushes the button those who don t receive 0 points while those who do receive 1 point A Push button