Brainstorming Definition

BrainstormingBrainstorming is a widely used method to stimulate creativity in problem solving. In a structured session, people (usually in a group) generate as many creative ideas as possible. Social psychologists have mainly studied whether it is more effective to brainstorm in a group or alone, and have come to the counterintuitive conclusion that brainstorming often is better done alone.

Underlying the brainstorming procedure are two basic principles. First, people are encouraged to come up with as many ideas as possible, because the more ideas, the more likely it is that good ideas are among them (“quantity breeds quality”). Second, although eventually the quality of ideas should be evaluated, idea generation and evaluation are strictly separated (“deferment of judgment”), because fear of negative evaluation interferes with people’s creativity. There is evidence for both principles: Quantity and quality of ideas are positively related, and fear of evaluation is bad for idea quality.

Brainstorming is usually done in groups, and much research has studied the effectiveness of group brain-storming. These studies have consistently revealed that people generate more ideas and better ideas when they brainstorm individually as compared to when they brainstorm in a group. In these studies, the number of ideas generated by a group is compared to the number of ideas of the same number of people who brainstorm individually. Counting duplicate ideas (ideas generated by more than one person) only once, results show that N individuals generate more ideas than an N-person group. The difference is quite large and increases with group size.

One major factor that causes the so-called productivity loss of groups is production blocking: Group members have to wait for their turns to express ideas, because only one person can speak at any given time. Thus, group members block each other’s contributions, which hampers their idea generation.

At the same time, people generally think that their creativity is enhanced in a group and feel that overhearing others’ ideas is stimulating. And in fact, this also is true: There is evidence that listening to others generating ideas helps one’s own idea generation. However, production blocking completely overrides these positive effects in normal brainstorming sessions. If ideas are not articulated aloud but are shared on pieces of paper (brainwriting) or through computers (electronic brainstorming), production blocking can be eliminated. Indeed, groups can be more productive than individuals when ideas are exchanged on written notes or through computers, rather than articulated aloud.


  1. Paulus, P. B., Dugosh, K. L., Dzindolet, M. T., Coskun, H., & Putman, V. L. (2002). Social and cognitive influences in group brainstorming: Predicting production gains and losses. In W. Stroebe & M. Hewstone (Eds.), European review of social psychology (Vol. 12, pp. 299-325). Chichester, UK: Wiley.
  2. Stroebe, W., & Diehl, M. (1994). Why groups are less effective than their members: On productivity losses in idea-generating groups. In W. Stroebe & M. Hewstone (Eds.), European review of social psychology (Vol. 5, pp. 271-303). Chichester, UK: Wiley.