Effect of Information Display on

Cooperation in a Public Goods

Dilemma under a Selective-Play Protocol

Department of Psychology

The Chinese University of Hong Kong

Hong Kong, China

Winton Au

Fion Law

Lestin Lee

How to promote cooperation under

endowment heterogeneity?

Au, W. T., Law, Y. K., & Lee, Y. H. (2009, August). Effect of information display on cooperation in a public goods dilemma under a selective-play protocol. Paper presented at The 13th International Conference on Social Dilemmas, Kyoto, Japan.

Selective Play• An option for leaving the

relationship and choosing a new partner (Hayashi & Yamagishi, 1998; Orbell & Dawes, 1991; Tesfatsion, 1995)

– “Choice to exit” A trinary-choice game in a PDG (Orbell, Schwartz-Shea, & Simmons, 1984; Hauk, 2003)

– “Fully-fledged selective play” (Yamagishi, Hayashi, & Jin, 1994; Yamagishi and Hayashi, 1996)

• Switch among groups (Ehrhart & Keser, 1999)

• Bid for partners (Coricelli, Fehr, & Fellner, 2004)

• Rank partners (Page, Putterman, & Unel, 2002)

• Hypothesis: Freedom to choose partners enhances cooperation

Yamagishi & Hayashi (1996)

Display of Endowment Information– Endowment heterogeneity increases cooperation (e.g., Chan, Mestelman, Moir, & Muller, 1996;

Bergstrom, Blume, &Varian,1986)

– … decreases (e.g., Cherry, Kroll, & Shogren, 2005; Ledyard, 1995)

– … does not change (e.g., Warr, 1983; )

• Rich contributes more…– More efficacious, critical or efficient (e.g., Van Dijk & Wilke, 1994; Rapoport, 1988; Diekmann, Przepiorka, &

Wehrli, 2009)

– Altruistic (Becker, 1974)

– Inequality aversion (Bolton & Ockenfels, 2000; Fehr & Schmidt, 1999)

• … less …– Fair share (e.g., Buckley & Cronson, 2006; Kroll, Cherry & Shogren, 2007)

– Anticipatory reciprocity (e.g., Cherry, Kroll & Shogren, 2005)

– Group identification [reduced when inequality justified] (Smith, Jackson, & Sparks, 2003)

• Hypothesis: Display of endowment information affects cooperation

Display of Cooperation Information• Visual anonymity

– Anonymity of a person• Identifiability (Kerr, 1999; Cress & Kimmerle, 2008)

– Anonymity of a person’s behavior or decision

• Hypothesis: Display of [individualized] cooperation information enhances cooperation (e.g., Sell & Wilson, 1991; Cress & Kimmerle, 2008; Vuolevi & Van Lange, 2009; Weisel & Bornstein, 2009)

Experiment• Task

– Students allocating time between group project [cooperation] vs. individual examination [defection]

• Voluntary contribution mechanism• Linear payoff

• Endowment size• Randomized across trials

– 6 hours per week– 9– 12

• Display of cooperation information– Yes– No

• Display of endowment information– Yes– No

[cooperation]

[defection]

D D: 9 hrs. D: (38%) D: 9 hrs. (38%)

No info Endowment info Cooperation info Full info

120 seconds to select members

Experiment• Task

– Students allocating time between group project [cooperation] vs. individual examination [defection]

• Voluntary contribution mechanism• Linear payoff

• Endowment size• Randomized across trials

– 6 hours per week– 9– 12

• Display of cooperation information– Yes– No

• Display of endowment information– Yes– No

• Protocols of play– Self-selected– Forced-play

Self-selected play– 303 participants– 13-24 participants in an one-hour session– 10 games– HK$50 ( ￥ 620) show-up fee +– Bonus HK$40 - $102 (average $73)

• ￥ 500 - ￥ 1500 (average ￥ 900)• Two randomly selected participants

Forced-play– 303 participants– Yoked to the same groupings of self-

selected play

Select group members

Make contribution decision

Receive feedback

10 trials

GroupProjectHours

IndividualExamHours

TotalHours

GroupProjectScore

IndividualExamScores

TotalScores

TotalPayoffs

Results of Trial 2

Coop Info x Endow Info Display

Endow Info No Endow Info0.0

0.5

1.0

1.5

2.0

2.5

3.0

Amount of CooperationCoop Info No Coop Info

Endow Info No Endow Info10%

15%

20%

25%

30%

Proportion of CooperationCoop Info No Coop Info

Coop info enhanced cooperation

Coop Info x Endow Info Display

Endow Info No Endow Info0.0

0.5

1.0

1.5

2.0

2.5

3.0

Amount of CooperationCoop Info No Coop Info

Endow Info No Endow Info10%

15%

20%

25%

30%

Proportion of CooperationCoop Info No Coop Info

Hiding endow info enhanced cooperation

Coop Info x Endow Info Display

Endow Info No Endow Info0.0

0.5

1.0

1.5

2.0

2.5

3.0

Amount of CooperationCoop Info No Coop Info

Endow Info No Endow Info10%

15%

20%

25%

30%

Proportion of CooperationCoop Info No Coop Info

Effect of coop info most prominent in the absence of endow info

Endowment x Coop Info x Endow Info

6 9 1210%

15%

20%

25%

30%

35%

40%

33% 33%

30%

24%26% 26%

13%

16%14%

13% 13% 12%

Coop Info OnlyCoop & Endow InfoNo InfoEndow Info Only

Endowment

Coop

erati

on R

ate

When cooperation information was present, absence of endowment information affected low and medium endowment players the most

Endowment x Coop Info x Protocol

6 9 1210%

15%

20%

25%

30%

35% 34%32%

29%

22%

26% 26%

11%12%

11%

15% 15% 15%

Coop/Selected

Coop/Forced

NoCoop/Selected

NoCoop/Forced

Endowment

Coop

erati

on R

ate

Low and medium endowment players most affected by possibility to choose partners when cooperation information was displayed

When heterogeneity

exists

• Allow selection of players• Hide endowment info and• Display cooperation info

– Most effective for less rich people