Abstract
Research has shown that processes of social comparison as well as persuasive argumentation are involved in group polarization. We propose a processing effort account according to which the role of these processes in determining group polarization is contingent on ability and motivation. The impact of information regarding others' positions on group polarization should be higher given low (vs. high) ability or motivation. In contrast, the impact of persuasive argumentation should be higher given high (vs. low) ability and motivation. Results in line with these assumptions were obtained in two experiments in which individuals' ability (Experiment 1) or motivation (Experiment 2), information regarding group average position, and argument persuasiveness were manipulated. Furthermore, consistent findings were also obtained in a third experiment testing the role of motivation in real group discussions. A processing effort account provides a novel perspective for investigating the development of group extremity.