Gaining and losing social support: Momentum in decision-making groups.

This paper addressed the question, is there a momentum effect in decision-making groups? That is, does movement toward a decision alternative encourage further similar movement? In the first two of three experiments, the movement of group members toward or away from a subject's preference was manipulated while holding constant the content of group discussion. The only significant effect of such shifts in position was an antimomentum effect; e.g., subjects were less likely to move toward an alternative which had gained a supporter than if no such shift in position had occurred. These experiments also demonstrated that the inverse relationship between overall level of support and likelihood of changing one's position (the “strength-in-numbers” effect) was not solely attributable to larger factions' ability to generate more arguments than smaller factions. In a final experiment, subjects were given an opportunity to defend their preference; under these conditions, the loss of a supporter might result in momentum-producing attributions (e.g., my arguments are unconvincing). However, these experimental conditions did not produce a momentum effect. Analyses of the content of subjects' speech paralleled the data on opinion change in these and previous studies—subjects were much more sensitive to current levels of support than to changes in the level of support. The antimomentum effect observed in Experiment 2 was attributed to a sensitivity to both one's current and past levels of support in the group.