1. By: Isaiah Magpali-Isaac, Tatianna Smith, Viris Colmenero Farrelly, Daniel, Lazarus, John, & Roberts, Gilbert (2007). Altruists Attract. Evolutionary Psychology. 5, 313-329.

2. Introduction  Research article sets out to answer the broad question: “Why humans are so cooperative?” Says it goes beyond theories of kinship and reciprocal altruism  People tend to cooperate on one-shot Prisoner’s Dilemma (PD) games despite the rational choice being to defect. Lead to a number of new ideas. Two being indirect and strong reciprocity ○ Indirect- one does altruistic things to build reputation so that others will help them when the time calls for it ○ Direct- tendency to cooperate with others and punish defectors Farrelly, Daniel, Lazarus, John, & Roberts, Gilbert (2007). Altruists Attract. Evolutionary Psychology. 5, 313-329.

3. Introduction (cont.)  One of the ideas was cooperation and altruism sometimes function as sexually selected displays that attract mates (directly or through reputation). Acts to enhance mating success, not through reciprocation or increased survival of relatives.  Altruism is important in long-term human relationships Efficient sharing of resources  Suggestive evidence that cooperative individuals are more attractive.  Evidence that males on their own give more to female than to male beggars. Farrelly, Daniel, Lazarus, John, & Roberts, Gilbert (2007). Altruists Attract. Evolutionary Psychology. 5, 313-329.

4. Objectives  Tested four key predictions of the sexual selection hypothesis: 1. participants should be more cooperative with individuals of the opposite sex 2. participants should be more cooperative when opposite sex partners are more attractive, and therefore of higher mate quality 3. the strength of the signal should increase with the strength of sexual selection. ○ as females are the choosier sex, males are under stronger sexual selection and should therefore show a stronger cooperative bias in the first two predictions. 4. the signal to benefit the signaler (altruist), receivers should be more likely to mate with signalers ○ more cooperative partners should be judged to be more attractive Farrelly, Daniel, Lazarus, John, & Roberts, Gilbert (2007). Altruists Attract. Evolutionary Psychology. 5, 313-329.

5. Subjects/Procedures/Methods  Subjects 231 participants from Newcastle University recruited via e-mail ○ 85 males and 146 females  Procedures & Methods Entire experimental procedures conducted on-line Database of pictures supplied had been previously rated for attractiveness on a scale of 1-5 ○ Top and bottom three rated pictures from both sexes ○ MH = high attractive male; ML = low attractive male; FH = high attractive female; FL = low attractive female Farrelly, Daniel, Lazarus, John, & Roberts, Gilbert (2007). Altruists Attract. Evolutionary Psychology. 5, 313-329.

6. Procedures/Methods (cont.)  Procedures and Method (cont.) Asked to rate individuals before they interacted with them in the game on four different attributes. ○ Rate out of 10 (1=Low, 10=High) ○ “Attractiveness” only important attribute Participants played four games ○ Mutualism Game ○ Prisoner Dilemma (PD) ○ Dictator games – Standard Dictator (SD) & Charity Dictator (CD) Farrelly, Daniel, Lazarus, John, & Roberts, Gilbert (2007). Altruists Attract. Evolutionary Psychology. 5, 313-329.

7. Procedures/Methods (cont.) Asked to make a decision in each of the games ○ Mutualism and PD asked to ‘give’ or ‘keep’ a certain amount of money ○ Or to invest money ranging in amounts (0-10) in the Dictator games (SD & CD) Picture of current partner remained on the screen the whole time. After completed the games participants were randomly assigned to one of two groups ○ Partner Highly Cooperative ○ Partner Less Cooperative Asked to rate partner again on four different attributes, ‘attractiveness’ being the only important one Farrelly, Daniel, Lazarus, John, & Roberts, Gilbert (2007). Altruists Attract. Evolutionary Psychology. 5, 313-329.

8. Procedures/Methods (cont.) [SETB]  Procedures and Method (cont.) Participants played four games ○ Mutualism Game (partners do better cooperating) ○ Prisoner Dilemma (rational decision is defection but cooperation works better if using sense of fairness and trust partner to cooperate) ○ Dictator games – Standard Dictator (SD) (rational to defect) & Charity Dictator (CD) (rational to defect but told beneficiary is charity) Asked to rate individuals before they interacted with them in the game on four different attributes (intelligence, attractiveness, cooperativeness, and how interesting they thought they were) ○ Rate out of 10 (1=Low, 10=High) ○ “Attractiveness” only important attribute Participants played with all four individuals in one of the four selected games (game type and partner identity were randomized) ○ Participants were told their partner had already made a decision about what they would do prior to knowing any knowledge of whom they would be playing ○ Picture of current partner was on screen throughout each game while participants asked to make decision ○ All the games were played and then participants were given the results of the partner ○ Participants were randomly assigned to two conditions in one condition all the partners were highly cooperative, and in the other condition they had been less cooperative ○ After this all participants rated each partner again in the four attributes Farrelly, Daniel, Lazarus, John, & Roberts, Gilbert (2007). Altruists Attract. Evolutionary Psychology. 5, 313-329.

9. Video  http://www.youtube.com/watch?v=ED9g aAb2BEw&feature=related Dilbert Prisoner's Dilemma http://www.youtube.com/watch?v=ED9g aAb2BEw&feature=related Farrelly, Daniel, Lazarus, John, & Roberts, Gilbert (2007). Altruists Attract. Evolutionary Psychology. 5, 313-329.

10. Results  Mutualism Game All participants chose to donate  Prisoners Dilemma Both sexes cooperated more with more attractive members of the opposite sex ○ ex. Men more likely to cooperate with FH as opposed to FL  Standard Dictator Game Males showed strong preference for giving to females rather than other males Both sexes showed preference for giving to more attractive members of the opposite sex  Charity Dictator Game Males gave more to females But Females gave more to female partners than to male partners Attractiveness effects were the same as in SD game  Predictions Mixed results were found that participants should cooperate more with opposite sex partners (not supported) All three games supported that participants were more cooperative towards more attractive members of the opposite sex Mixed results were found males showed greater bias towards opposite sex partners than females (not supported) As predicted more cooperative partners were rated as more attractive Farrelly, Daniel, Lazarus, John, & Roberts, Gilbert (2007). Altruists Attract. Evolutionary Psychology. 5, 313-329.

11. Study Strengths  Participants were randomized to conditions  The Methods section was very thorough and clear (detailed how each game was played)  It was interesting how in all the games neither sex showed an attractiveness bias when interacting with their own sex Farrelly, Daniel, Lazarus, John, & Roberts, Gilbert (2007). Altruists Attract. Evolutionary Psychology. 5, 313-329.

12. Study Weaknesses  Did not specify how long each game took, participants could have lost interest because they played 4 games  Participants were recruited voluntarily via- email and posters placed around campus which may target a certain type of person that would volunteer for this study  Participants were not actively playing the game (participants were told partners had made decisions prior to the game). Neither were they playing in actual person. Farrelly, Daniel, Lazarus, John, & Roberts, Gilbert (2007). Altruists Attract. Evolutionary Psychology. 5, 313-329.

13. Quiz  1. What was not measured in this study a. participants cooperation with the opposite sex b. participants cooperation with a range of attractive and non attractive members of the opposite sex c. participants cooperation with people of the opposite sex they had previously met d. participants cooperation with the same sex  2. Which one of the four attributes that the participants were asked to rate their partners on was the only one used in this study a. intelligence b. attractiveness c. cooperativeness d. how interesting they thought they were  2. In the Dictators game it was most rational to a. defect b. cooperate c. share d. Cooperate if you trust partner to cooperate  4. T/F Participants rated each partner twice on the four attributes  5. T/F In the Charity Dictator Game males gave less to females  6. T/F All three games supported that participants were more cooperative towards more attractive members of the opposite sex Farrelly, Daniel, Lazarus, John, & Roberts, Gilbert (2007). Altruists Attract. Evolutionary Psychology. 5, 313-329.

14. Reference  Farrelly, Daniel, Lazarus, John, & Roberts, Gilbert (2007). Altruists Attract. Evolutionary Psychology. 5, 313-329. Farrelly, Daniel, Lazarus, John, & Roberts, Gilbert (2007). Altruists Attract. Evolutionary Psychology. 5, 313-329.