Unanimous versus Majority Influences on Group Polarization in Business Decision Making

Abstract This study compared whether unanimous- or majority-opinion groups would polarize to a greater extent on their opinions. Singaporean management students (N = 259) evaluated three business projects on safety and favorability, selected one to be financially supported, and indicated the certainty of their choice. Subjects were then randomly assigned to 3- or 4-person groups, directed to discuss the projects, and asked to complete the previous ratings as a group. Only groups that chose the same projects were analyzed (36 unanimous and 39 majority groups). Two-tailed t tests were computed to compare pre- and postdiscussion mean scores on all three attitude measures. Polarization occurred for both groups, with five of the six mean differences highly significant (p < .001). Evidence of greater polarization among unanimous groups was also found, suggesting that the presence of a single dissenting member in a decision-making group can moderate the polarization dynamic.