The Medium or the Message? Communication relevance and richness in Trust games

1. The Medium or the Message?Communication relevance and richness in Trust games Cristina Bicchieri University of Pennsylvania http://www.phil.upenn.edu/faculty/bicchieri (work done in collaboration with Azi Lev-On and Alex Chavez)

2. The ‘communication effect’: • First found in Social dilemma experiments • Face to face communication • Communication increases cooperation 40% over base rate (Ledyard 1995, Sally 1995) • Effect still present in computer-mediated communication (Bicchieri and Lev-On 2007), but • Richness of medium matters (video, text) • More time than FtF to establish cooperation • Syncronous communication better

3. Why communication matters? • Group identity (Dawes et al. 1977) • Irrelevant communication may increase group identification, but cooperation stays low (17% in Bouas and Komorita, 1996) • Distinguish relevant from irrelevant communication (Gachter and Fehr, 1999) • Only discussion of game matters to cooperation • Relevant communication always involves promising (Bicchieri, 2002)

4. Promising focuses subjects on social norms (promise keeping, reciprocity..) (Bicchieri, 2002, 2006), however: • Background conditions of communication affect credibility of mutual promises • Cues generated by FtF communication (visual, verbal, social) correlated with trustworthiness • Enable formation of empirical and normative expectations of compliance • Conditional preference to conform • In social dilemma experiments with CMC, promises not perceived as credible  low cooperation (Brosig et al, 2003; Zheng et al., 2002). Group size fixed

5. Experiments: • Trust games • Relevant/Irrelevant communication • Face to face/Computer-mediated • Dyadic/Group communication

6. Experiment 1 (Bicchieri, Lev-On and Chavez, 2009) • 64 participants • Each plays 3 Trust games, randomly paired with different partners • No feedback on amount returned • Paid on two games, randomly chosen • 5 experimental conditions: • G1.1,2: control, no communication • G2.1: Computer based text chat (5 min.), relevant • G3.1: FtF communication (2 min.), relevant • G2.2: Computer based text chat (5 min.), irrelevant • G3.2: FtF communication (2 min.), irrelevant

7. after decision in each game, 1st movers asked about expectation of 2nd mover reciprocation • analyze effects of communication relevance and medium on trust (how much is sent), reciprocity (amount returned relative to amount sent), and expected reciprocity (expected amount returned relative to amount sent) • Relative to control, both relevance and medium had large, positive effect on all three dependent variables

8. Experiment1- Some Results Mean trust, reciprocity and expected reciprocity by communication relevance and medium

10. Trust: • Greater trust with relevant communication (majority sends $6) • No effect of communication medium on trust • Trust increases with expected reciprocity • Message relevance most conducive to create such expectations • Reciprocity: • Bimodal pattern, either 0 or $9 • Affected by medium and amount sent • Pattern depends on conditions: • -- FtF relevant: almost all return $9 • -- Control: almost all return zero • -- When 1st movers send less than $6, little is returned

11. Controlling for type of communication, the medium had no significant effect on trust • The behavior of first-movers is strongly determined by their expectations of second-movers' reciprocation • Note, however, that those expectations are rarely met, as expected reciprocation was significantly higher than the actual reciprocation, across all conditions

12. Our results also suggest that the variable most conducive to creating such expectations is not the medium, but rather the message. • First-movers' investments were significantly higher following unrestricted communication than restricted or no communication. • Communication always involves promising to trust/reciprocate

13. When communication was restricted, there were no significant differences between the amounts sent following CMC and FtF communication, and the no-communication control

14. Experiment 2 (Lev-On, Chavez and Bicchieri, 2009) • 60 participants • Each plays 3 Trust games, randomly paired with different partners • No feedback on amount returned • Paid on two games, randomly chosen • 5 experimental conditions: • G1.1,2: control, no communication • G2.1: Dyadic computer based text chat (5 min.), relevant • G3.1: Dyadic FtF communication (2 min.), relevant • G2.2: Group computer based text chat (10 min.), relevant • G3.2: Group FtF communication (5 min.), relevant

15. Mean trust, reciprocity and expected reciprocity by communication medium and group size

16. Some results

17. As a general rule, higher levels of trust, reciprocation, and expected reciprocity were recorded in the dyadic conditions, compared to the non-dyadic conditions • The medium of communication did not significantly predict trust • Trust level depends on group size and communication • Reciprocity depends on trust, group size, medium -- probability returning each $ increases with amount sent, but increases more rapidly for dyadic conditions, and most rapidly for FtF dyadic

18. Bimodal pattern of returns (zero or $9) -- pattern depends on communication condition, only partially on trust levels -- almost all 2nd movers in dyadic FtF return $9 -- almost all 2nd movers in control and CMC-group return zero • Expected reciprocity is highest in dyadic communication  promises are more frequent  highest level of trust • If group makes promises, trust/reciprocity more frequent than control

19. Implications for Cooperation in Computer-Mediated Environments • Virtual work groups • File sharing sites • Web-supported collective action • Interface Design • Create opportunity for dyadic communication • Video vs. audio conversation