Expanding the Persuasive Arguments Explanation of the Polarity Shift: A Linear Discrepancy Model

Abstract

In this paper the persuasive arguments explanation of the polarity shift is expanded by articulating the process by which group members come to a decision. This process is hypothesized to be a persuasion process. It is suggested that persons modify their opinions as a linear function of the discrepancy between their opinion and the opinions advanced by others; the greater this discrepancy the greater the opinion change. This model is termed the linear discrepancy model, and two versions of the model are developed. In one version it is assumed that all group members speak equally during the group discussion, and in the second version this restriction is relaxed to include instances of unequal speaking. The implications of this model are derived, and an experiment to test the model is presented. With little exception the data prove to be congruent with the model. The two versions of the model fit the data equally well. The argument is advanced that the unequal speaking model is preferable on logical grounds, and the excellent fit of the equal speaking model is attributed to the fact that the group discussions were short and without large discrepancies in speaking time.