This research represents an attempt to determine the impact of a group decision support system (GDSS) on the ability of groups to influence the judgments of individual group members. The power of groups to influence individuals has been well documented in the social psychological literature. For organizations interested in promoting innovation and creative problem solving in group settings, this tendency can be quite troubling. In the past, researchers have looked at how certain types of GDSSs might lessen these types of group pressures in the generation of creative ideas. This research may be viewed as an extension of this work to the choice phase of decision making. In an experimental setting forty-eight subjects were combined on an individual basis with groups of confederates to test the normative influence of the groups on the choices made by the individuals. Three different communication modality configurations were employed to test the effect which this had on the influence of the group. Whereas negative group effects in the idea-generating phase may lead to good ideas not being considered, group effects in the choice stage can to lead poor decisions being adopted, perhaps with even more unfortunate results. Obviously, both of these effects represent serious threats to the effectiveness of decision-making groups; consequently, both represent areas for potential contribution of improved versions of GDSSs.