This study was conducted to examine the effects of discussion to decide social rules on attitudes of undergraduates. Participants were first asked to indicate how bad they individually thought was the behavior that ignored a social rule, and wrote reasons for their judgment. Then half of them were told that everyone in the local community participated in the discussion to make it as the community rule, while the others were told that the community simply made it for members to follow. They were asked to make judgment on legitimacy of the rule. In Study 1, two groups were not significantly different in their judgment. In Study 2, conditions of perspective-taking and bottom-up procedure were added, and the participants in a discussion group thought that rule-making was more justifiable than those in a control group where the leader made the rule, if others’ opinions, for and against making the rule, were shown, and the community was supposedly started anew. The difference was statistically significant, regardless of which domain that the participants thought the judgment pertained to: moral, conventional, personal, personal-moral, or contextually-conventional. In Study 3, half of participants actually had a discussion with another, and again those in the discussion group agreed more that the rule-making was justifiable, replicating the results of Study 2.

Key words: discussion, social rules, attitudes toward social rules, domains of judgment