An Experimental Physiological Approach to Group Decision Making: Consensus Rule vs Majority Rule

We examined the quality of decisions made by groups under either majority rule (MR) or consensus rule (CR). Theoretically, engagement may be a factor. Measures of engagement in three-person groups included self-reports (not analyzed at this time), counts of the number of participant utterances during discussions, and changes in electrodermal activity (EDA; formerly known as galvanic skin responses). We predicted that engagement, based on number of utterances, would be greater under CR discussions, which are open-ended, rather than those under MR, which are focused; conversely, under MR, we predicted that average GSR responses would be greater, indicating more focus on the problem at hand. Participants working under the consensus condition spoke significantly more often during discussions than those under MR. As also predicted by theory, after de-trending the GSR data, we found that MR produced an average higher GSR and shorter discussion times. We also describe our most recent preliminary work in which group size has been increased to five participants, and groups have been given the Wason Selection Task as a puzzle to solve. Group sizes will eventually be increased to seven subjects.