Takehiro Ito’s research while affiliated with Iwate Prefectural University and other places

We examine how group decision-making affects other-regarding behavior in experimental dictator games. In particular, we assess whether the effects of iterated games differ for group and individual decision-making and whether the difference in decision-making style (individual or group) changes the perception of social identity. We make two findings on group decision-making. First, group decisions become more selfish when repeating the game after changing group members. Second, a dictator group donates more to a recipient group at the same university than to a recipient group at a different university. These findings are not true for individual decision-making.

This paper examined effects of the preceding experiment, in which participants play an repeated impunity game, to the additional experiment in which the same participants play an one-shot impunity game. This paper's findings are as follows: The average offer in the additional experiment was not significantly different to that in the first round in the repeated game. On the other hand, the average of supremum of the money amounts the respondents predetermined to reject the offer in the additional experiment was significantly less than that in the first round in the repeated game.

本稿は，一方的最後通牒ゲームを同じ二人の被験者間で繰り返し行う条件と，毎回異なる相手と繰り返し行う条件を比較することで，提案者が金銭を分配するときにnon-monetary punishmentに対する互恵性が存在するかどうかを検討した．実験の結果，一つ目の条件では応答者が提案を承諾すると拒否した場合よりも提案者は次のラウンドで高い分配額を提案するが，二つ目の条件ではそうならないことがわかった．この結果は，金銭を分配する人々の行動がnon-monetary punishmentに影響を受け，さらに互恵的に振る舞うことを示唆している． Comparing the results obtained in an experiment on the fixed matching impunity game with multiple rounds and those obtained in an experiment on the random matching impunity game with multiple rounds, we examine whether reciprocity under the condition of non-monetary punishment exists when proposers distribute money. The experimental results indicate that, in the fixed matching treatment, proposer participants offered more money to receiver participants when the receiver participants had accepted the offer in the last round than when the last offer was rejected, but in the random matching treatment, proposer participants did not. This result suggests that proposers can be affected by non-monetary punishment and act on a reciprocal basis.