1. Are We Really the Champions of Reciprocity? Incomplete Information About Others’ Behavior Undermines Cooperation and Reciprocity Joel Vuolevi & Paul van Lange Dept of Social Psychology, VU University, Amsterdam, the Netherlands 13 th International Conference on Social Dilemmas, Japan, Kyoto, 20 th – 24 th August 2009

2. The “psychology” of incomplete information Complete Information: “The other allocated 7 coins out of 10” Reciprocity is a matter of simple choice Incomplete Information: The other’s behavior subject to interpretations Reciprocity depends on inferences regarding other’s previous behavior The other’s previous behavior

3. How do we “fill-in” the missing pieces of information in others’ behavior? People think that others’ behavior stems from self- interest (Miller & Ratner, 1998) People think of themselves as more moral and honest than others (Allison, Messick, Goethals, 1989, Lange & Sedikides, 1998) Global judgments about other people in general are guided by a belief in the self-interest of others. To start with, how about without having any information at all – people’s beliefs about other people in general

4. Do global judgments influence evaluations of concrete behavior? Under incomplete information, people fill-in the blanks of concrete other person’s behavior with self- interest: The Dice Rolling Paradigm (Vuolevi & Van Lange, EJSP, in press).

5. The research question Under no information, people believe that other people are self-interested Under incomplete information, the belief in others’ self-interest distorts judgments of overt behavior Does the belief in others’ self-interest influence the way in which we respond to others under incomplete information? No longer the champions of reciprocity?

6. Coin paradigm: Method Sequential task: 1) Other’s allocation 2) Information 3) Estimation 4) Own allocation etc. Pps were told that “the other” had allocated 16 coins Pps clicked coins to see which of them the other allocated to oneself or to the participant Fair allocations (8/8) IV: number of coins displayed DVs: estimation and allocation

7. Study 1: Results With less information pps underestimate cooperation and cooperate less People reciprocate the number of coins they believe they have received (=perceived vs. true reciprocity).

8. Study 2 Tit-For-Tat (TFT) as the basic strategy instead of the fairness strategy – provides a more realistic baseline A true dilemma – coins worth more for the other person - - incentive for cooperation A cooperation manipulation - how people respond to others who are more/equally/less cooperative than the pps Design: 2 (information: low vs. high) by 3 (strategy: TFT- 2, TFT, TFT+2)

9. Study 2: DV: Cooperation Also with TFT pps cooperate less in the low information condition Reciprocity is more complete in the high information condition than in the low information condition Cooperation is challenging to communicate under high level of incompleteness of information

10. Study 2: DV: Person Perception = impression of benign intent (Van Lange et al, 2002) The less information the more negative person perception The other’s behavior influence person perception in the high information condition, but much less in the low information condition

11. Conclusions Incomplete information is a part of everyday life – especially when making inferences about others’ behavior In incomplete information situations both beliefs and information influence inferred cooperation With low levels of information behavior is guided by self- interest beliefs, with high levels of information by reciprocity Perceived reciprocity: responding in kind becomes responding in mind Reduced cooperation is rooted in people’s tendency to underestimate others’ cooperation

12. Why do we underestimate others’ cooperation? My good intentions vs. your bad behavior (Pronin, 2008) Behavior is often influenced by unintended errors (Van Lange et al, 2002) and situational constraints (Jones and Davis, 1965) Not to lose is more valuable than to gain (Kahneman & Tversky, 1979; Baumeister et al, 2001)

13. Take Home Message We truly believe that we are the champions of reciprocity, but we fail to see if others actually are. We are not the champions of reciprocity Through acting upon self-created beliefs, incomplete information forms a serious threat to the development of human cooperation