In the group discussion, decision may be made with less satisfaction because of conformity pressure.
In order to solve this problem, we developed a telecommunication system for improving persuasive power by showing the number of minorities more than they actually are. This system is based on psychological knowledge "Multiple source effect" that information from multiple sources is more persuasive than from a simple source.
As a result of experiments, it was suggested that the proposed system improved the persuasive power of minorities and degree of satisfaction with decision.