title: Rejection of unfair offers in the ultimatum game is no evidence of strong reciprocity.
abstract: The strong reciprocity model of the evolution of human cooperation has gained some acceptance, partly on the basis of support from experimental findings. The observation that unfair offers in the ultimatum game are frequently rejected constitutes an important piece of the experimental evidence for strong reciprocity. In the present study, we have challenged the idea that the rejection response in the ultimatum game provides evidence of the assumption held by strong reciprocity theorists that negative reciprocity observed in the ultimatum game is inseparably related to positive reciprocity as the two sides of a preference for fairness. The prediction of an inseparable relationship between positive and negative reciprocity was rejected on the basis of the results of a series of experiments that we conducted using the ultimatum game, the dictator game, the trust game, and the prisoner's dilemma game. We did not find any correlation between the participants' tendencies to reject unfair offers in the ultimatum game and their tendencies to exhibit various prosocial behaviors in the other games, including their inclinations to positively reciprocate in the trust game. The participants' responses to postexperimental questions add support to the view that the rejection of unfair offers in the ultimatum game is a tacit strategy for avoiding the imposition of an inferior status.
authors.affiliation: Brain Science Institute, Tamagawa University, Machida, Tokyo 194-8610, Japan. yamagishitoshio@gmail.com
authors.forename: Toshio
authors.initials: T
authors.lastname: Yamagishi
authors.forename: Yutaka
authors.initials: Y
authors.lastname: Horita
authors.forename: Nobuhiro
authors.initials: N
authors.lastname: Mifune
authors.forename: Hirofumi
authors.initials: H
authors.lastname: Hashimoto
authors.forename: Yang
authors.initials: Y
authors.lastname: Li
authors.forename: Mizuho
authors.initials: M
authors.lastname: Shinada
authors.forename: Arisa
authors.initials: A
authors.lastname: Miura
authors.forename: Keigo
authors.initials: K
authors.lastname: Inukai
authors.forename: Haruto
authors.initials: H
authors.lastname: Takagishi
authors.forename: Dora
authors.initials: D
authors.lastname: Simunovic
mesh_terms: D000328:Adult; D000368:Aged; D001242:Assertiveness; D003299:Cooperative Behavior; D005260:Female; D005716:Game Theory; D006801:Humans; D008297:Male; D008875:Middle Aged; D018803:Models, Economic; D008960:Models, Psychological; D012945:Social Values; D055815:Young Adult