1. Pablo Brañas1 Mari Paz Espinosa2 Jaromir Kovarik2
Paper 1: Altruism and Social Integration Paper 2: Inequity Concerns in Social Networks
Pablo Brañas1
Mari Paz Espinosa2
Jaromir Kovarik2
Ramon Cobo Reyes1
Natalia Jimenez1
Giovanni Ponti3
1Universidad de Granada, 2 Universidad del País Vasco, 3 Universidad de Alicante

2. Main Question
Is the prosociality of people - altruism and inequity aversion - related to their position in social structures - centrality?

3. Motivation I
It has been observed that the level of social conerns of individuals is affected by many aspects:
Entitlement (List and Cherry, 1999)
Social distance (Leider et al., 2006)
Framing (Tversky and Kahneman,1981)
Anonymity (Hoffman et al., 1994, 1996) …

4. Motivation I
It has been observed that the level of social conerns of individuals is affected by many aspects:
here
How does the level of generosity depends on social network position?

5. Motivation II
The evolutionary literature argues that social norms coevolves with social networks (Boyd & Richerson, JTB 2002; Marsili et al., PNAS 2004; Nowak, Nature 2006; …)
If social norms and social structures indeed coevolve, we should observe some relation between the degree of prosociality of individuals and their network position.
here

6. Altruism and Social Network
Experiment 1:
Altruism and Social Network

7. Altruism and Network I 2 stages: Network elicitation
Indegree, outdegree, reciprocal degree
(local measures of connectivity)
Betweenness (global measure) – number of shortest path from two individuals passing through node i
(how the removal of node i affects the overall connectivity of the network)

8. Altruism and Network I 2 stages: Network elicitation
Dictator game – divide 10 coins between you and other person
3 treatments:
(i) standard dictator game
(ii) Friends – network distance = 1
(iii) Framing – “would rely on you”

9. Altruism and Network II

10. Altruism and Network III

11. Altruism and Network IV
Are more central individuals more generous?
2 dependent variables:
Altruism – dictators’ gifts
Selfishness = 1 if the gift is 0 or 1
= 0 otherwise

12. Altruism and Network V

13. Altruism and Network V

14. Altruism and Network VI

15. Conclusions:
(1) Less generous individuals tend to be play a peripheral role in the network (both from local and global perspective). (2) People who do not share are not central and do not share independently of the situation they face.

16. Inequity Concerns (IC) within Social Networks
Experiment 2:
Inequity Concerns (IC) within Social Networks

17. IC and Network I Motivation:
solve the “problems” of the previous study
Complete network ( larger sample size; 3X)
Different sharing rule (rather than pure generosity)

18. IC and Network II
(data from Brañas, Duran, Espinosa, forthcoming in Rationality and Society)
2 stages:
Network elicitation (<300 subjects)
Inequity Aversion game (n= 169, 2 stages)
Stage 1: variation of the Dictator game
(S,0)
(0,S)

19. IC and Network II
(data from Brañas, Duran, Espinosa, forthcoming in Rationality and Society)
2 stages:
Network elicitation (<300 subjects)
Inequity Aversion game (n= 169, 2 stages)
Stage 2: the Dictator is given a possibility to repair at his cost the created inequality:
“How much are you willing to pay for subject who have not received anything to get S as well?”

20. IC and Network II
(data from Brañas, Duran, Espinosa, forthcoming in Rationality and Society)
2 stages:
Network elicitation (<300 subjects)
Inequity Aversion game (n= 169, 2 stages)
2x2 factorial design:
Friends
Personal involvement in the divided amount

21. IC and Network III

22. IC and Network IV
The dependent variable measures the inequity concern of each individual with respect the median willingness to pay to repair the inequality

23. IC and Network V (1) (2) (3) (4) Indegree .117 (.082) - Outdegree
.289 (.097)***
Reciprocal degree
.231 (.116)**
Betweenness
.00034*** (.00013)
Gender
-.327 (.278)
-.395 (.282)
-.338 (.281)
-.370 (.279)
N = 169 ; Gender = 1 for males ; *** 1%, ** 5%, * 10%

24. Conclusion
We reinforce that social embeddedness is an important factor (globally and locally) to determine the degree of prosociality (non-selfishness).

25. Causality Problem
Are people more generous because they are important in their circles, or do they play a prominent role because they are for whatever reason more prosocial? Solution: Experimental design issue on which we already work.