Stroebe and Diehl(1994) conducted a clever piece of research into why brainstorming does not appear to enhance individual creativity. They hypothesized that, during a brainstorming session, because may speak at a time, other group members have to keep silent, and may be distracted by the content of the group discussion or forget their own ideas. Storebe and Diehi termed this phenomenon ‘production blocking’, because the waiting time before speaking and the distracting influence of others ‘ idea could potentially block individuals from coming up with their ideas. The result of their subsequent study were clear-cut: participants generated approximately twice as many ideas when they were allowed to express their ideas as they occurred than when they had to wait their turn. But which two of the following can we infer from these results? 1.That ‘production blocking’ does not occur in interactive brainstorming groups. 2.That ‘production blocking’ is an important factor explaining the inferiority of interactive brainstorming groups. 3.That it may be more effective to ask group members to develop their ideas in one group, and than express them to another group. 4.That it may be more effective to ask group members to develop their ideas separately, and then express them in a subsequent joint meeting.