RISE and FALL of COOPERATION Jun Kobayashi (Seikei U) Yuhsuke Koyama (Tokyo I of Tech) Hideki Fujiyama (Dokkyo U) Hirokuni Oura (Teikyo U) August 15, 2005 ASA, Philadelphia
OVERVIEW Mutual Effects of Group Cooperation Rate & Group Size? (traditional) Social Dilemma Experiment w/ Intergroup Mobility (Not traditional)
3 Olson... Size↑→Cooperation↓ Free-rider Problem, Social Dilemma Counter Effect? Modern Societies… Exit Option Moving, Job change, Divorce Effect of Group Cooperation Rate on Group Size??? QUESTION
ON the RUN (Erhart + Keser) Experiment, Intergroup Mobility 9 players in 3 group, 10 Sessions Cooperators RUN AWAY Cycle: Size↑→Cooperation↓→ S↓→C↑ Various Conditions???
Introduction Data Result
6 2003/4, 4 universities in Japan 10 Sessions, 170 Students ¥ ($11), 90 minutes Computer-based, Group data “LOW” “MIDDLE” “HIGH” Mobility 17 in 4 Groups, Anonymous 10 Rounds, 9 Exit chances EXPERIMENT
7
8 ROUND (10 times) A B C D Exit Chance Free-rider Problem
9 Resource ¥ 20 PROVIDE or NOT Pooled Resources... DOUBLED...3/more-player groups x player Groups SAME... 1-player Groups EQUALLY Distributed in Group 1. FREE-RIDER PROBLEM
10 Provide = 40m/4 = 10m (Providers) Not = 40(m-1)/ = 10m + 10 Not Provide Not x 2 = EXAMPLE (4 Players)
11 LOW Mobility... ¥ 50 to Exit MIDDLE Mobility... ¥ 20 HIGH Mobility... ¥ 0 2. EXIT CHANCE
A B C D A B C D A 3 B4 C8 D 2 Groups’ Average Payoffs Last Stage Groups’ Average Payoffs in This Round Groups’ Size Group C Round 2 Stage 2 Your Decisions and Payoffs in This Round StageYour DecisionYour Payoff 1NOT PROVIDE 5.00 Your Total: 125 yens ( 20 yens subtracted for Moving) Group C's Members: You (ID 6) and Other 7 What do you do next stage? PROVIDE 20 yens NOT
Provided 20 yens: 3 persons Not: 4 persons Your Decision: Provide Your Payoff: yens
A B C D Groups’ Average Payoffs and Size last Round ROUND END Groups’ Average Payoffs GroupStage A B C D Your payoff Last Round: 112 yens in Group C Which Group in Next Round? Move with 50 yens Group A B C D
HYPOTHESES H1. Size↑→Cooperation↓ H2. Cooperation↓→ Size↓ H3. Mobility↑→Cycle Accelerated Size Cooperation Rate H1 H2 H1 H2
REGRESSION ANALYSES Unit… Group (N=360) H1. Size↑ Cooperation↓ Round Number, Previous Cooperation H2. Previous Coop.↓ Size↓ Round Number, Previous Size
Introduction Data Result
18 DESCRIPTIVE STAT.
H1. SIZE on COOPERATION
y = COOPERATION RATE * p<.05, **.01, ***.001 Mobility Cost ¥ 50 ¥ 20 ¥0¥0 ROUND.00 SIZE-.04***-.05***-.03* Previous COOP..47*** R2R
H2. COOPERATION on SIZE Size Previous Cooperation Rate
y = SIZE * p<.05, **.01, ***.001 Mobility Cost ¥ 50 ¥ 20 ¥0¥0 ROUND Previous COOP. 2.12***3.11***4.83*** Previous Size.83***.65***.36** R2R
H3. MOBILITY on CYCLE
Interaction Effects… Not Significant
EXAMPLES of CYCLE (LOW) Group A B C D
MIDDLE MOBILITY
HIGH MOBILITY
28 Large Groups DECREASE Cooperation, then SHRINK Then INCREASE Cooperation, then EXPAND MOBILITY ACCELERATES Cycle SUMMARY