Cristina Bicchieri
University of Pennsylvania
http://www.phil.upenn.edu/faculty/bicchieri
(work done in collaboration with Azi Lev-On and Alex
Chavez)
The ‘communication effect’:
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1.
2.
3.
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
Why communication matters?
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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)
Promising focuses subjects on social norms (promise
keeping, reciprocity..) (Bicchieri, 2002, 2006),
however:
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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
Experiments:
• Trust games
• Relevant/Irrelevant communication
• Face to face/Computer-mediated
• Dyadic/Group communication
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
• 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
Experiment1- Some Results
Mean trust, reciprocity and expected reciprocity by
communication relevance and medium
Control
FtF
relevant
CMC
relevant
FtF
irrelevant
CMC
irrelevant
Trust
2.63
5.57
5.14
4.17
3.28
Reciprocity
1.92
7.57
5.14
3.33
1.94
Expected
reciprocity
3.54
8.36
7.43
5.56
4.28
0 1 2 3 4 5 6
Amount Sent
0.8
0.0
0.0
0 1 2 3 4 5 6
CMC-Irrelevant
0.4
0.8
FtF-Irrelevant
0.4
0.8
0.0
0.0
0 1 2 3 4 5 6
CMC-Relevant
0.4
0.8
FtF-Relevant
0.4
0.8
0.4
0.0
Frequency
Control
0 1 2 3 4 5 6
0 1 2 3 4 5 6
Trust:
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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:
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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
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When communication was restricted, there
were no significant differences between the
amounts sent following CMC and FtF
communication, and the no-communication
control
Mean trust, reciprocity and expected reciprocity by
communication medium and group size
No
Comm.
FtF
Dyadic
CMC
Dyadic
FtF
group
CMC
Group
Trust
3.03
5.57
5.14
4.12
3.94
Reciprocity
1.83
7.57
5.14
3.62
2.12
Expected
reciprocity
3.50
8.36
7.43
4.31
5.00
Some results
0 1 2 3 4 5 6
Amount Sent
0.8
0.0
0.0
0 1 2 3 4 5 6
CMC-Group
0.4
0.8
FtF-Group
0.4
0.8
0.0
0.0
0 1 2 3 4 5 6
CMC-Dyadic
0.4
0.8
FtF-Dyadic
0.4
0.8
0.4
0.0
Frequency
Control
0 1 2 3 4 5 6
0 1 2 3 4 5 6
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As a general rule, higher levels of trust, reciprocation,
and expected reciprocity were recorded in the dyadic
conditions, compared to the non-dyadic conditions
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The medium of communication did not significantly
predict trust
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Trust level depends on group size and communication
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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
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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
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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
Implications for Cooperation in ComputerMediated Environments
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Virtual work groups
File sharing sites
Web-supported collective action
Interface Design
Create opportunity for dyadic communication
Video vs. audio conversation