طوفان مغزی و عملکرد وظیفه در گروه های محدود شده توسط شواهد

Group brainstorming is usually considered a task of divergent thinking, and the ideas produced in most research on brainstorming are counted and scored for creativity but put to no further use. We studied brainstorming by embedding it in a rule induction task that initially requires divergent thinking but increasingly requires convergent thinking as evidence accumulates across trials. We also tested whether brainstorming facilitated performance on the induction task itself. The experimental design was a 2 (nominal or interacting groups) × 3 (brainstorming early in the task, late in the task, or none) factorial. For brainstorming performance, nominal groups of 4 individuals outperformed face-to-face groups of 4 individuals. But as predicted from an analysis of the effects of constraining hypotheses by evidence, the advantage for nominal groups declined when brainstorming took place late in the task where there was a large amount of accumulated evidence to consider. Brainstorming did not generally affect performance on the induction task, although early group brainstorming resulted in more correct hypotheses than late group brainstorming. Group brainstorming was perceived as more effective than individual brainstorming by both interacting and nominal group members, a finding that extends the illusion of group productivity in brainstorming to tasks of convergent thinking.

Our findings challenge some of the implicit generalizations that follow from the large literature on group brainstorming that has employed tasks of divergent idea production. We found that face-to-face groups constrained by evidence show somewhat smaller deficits relative to nominal groups than did groups engaged in the part of the task involving divergent thinking. However, without comparing performance across a set of tasks that vary in solution demonstrability (Laughlin, 1980; Laughlin & Ellis, 1986) we do not know what the size of these differences might mean in practice. But the deficits are still there on highly constrained phases of the rule induction task and seem to be due to the same set of inhibitory forces that act on unconstrained groups. The usual textbook summary of brainstorming tends to imply that the inferiority of face-to-face brainstorming groups also suggests other deficits in group performance. On the contrary, we found that, for face-to-face groups generating hypotheses in the service of inductive problem-solving, brainstorming might have some facilitating effects on task performance. Future research might profitably study idea generation in a variety of contexts in which group products can be put to use.