Neural evidence for sudden insight

When a group of people work together to remember an event, the group do appear to recall more than an individual working alone, but do they recall more than the sum of the memories each individual recalls?

Studies have found that "brainstorming" groups actually produce fewer ideas than groups that are groups in name only₁. And in many tasks, from rope-pulling to vigilance tasks, it has been found that people contribute less when they are part of a group than when they are working alone₂.

In this study, two experiments compared the memory performance of nominal and collaborative groups of three, using

• random lists of pictures and words;
• a story (The "War of Ghosts", a supposed folk-tale, long used in psychology labs to demonstrate the errors in people's memories)

It was found that the nominal groups (where individual results were pooled) remembered the best. Collaboration appears to inhibit recall. Such collaborative inhibition was greater with the story than with the list.

References

1. Bouchard, T. J. Jr. & Hare, M. 1970. Size, performance, and potential in brainstorming groups. Journal of Applied Psychology, 54, 51-55.

Diehl, M. & Stroebe, W. 1987. Productivity loss in brainstorming groups: Toward solution of a riddle. Journal of Personality and Social Psychology, 53, 487-509.
Dunnette, M. D., Campbell, J. & Jaastad, K. 1963. The effects of group participation on brainstorming effectiveness for two industrial samples. Journal of Applied Psychology, 47, 30-37.

2. Karau, S.J. & Williams, K.D. 1993. Social loafing: A meta-analytic review and theoretical integration. Journal of Personality and Social Psychology, 65, 681-706.

Despite the popularity of brainstorming as a strategy for producing ideas and new perspectives, it appears that participation in a group actually reduces the number of ideas produced (compared to the number of ideas that would be produced if the participants thought independently)₁.

Three possible explanations have been investigated:

• evaluation apprehension (being worried how other people will evaluate your ideas)
• social loafing (a self-explanatory and rather cute description)
• production blocking (the group interaction interferes with your ability to express your ideas, e.g., through interruptions)

It was concluded that this last explanation (production blocking) was the most plausible reason for the reduction in idea production. It was suggested that a person's retrieval strategy is disrupted by hearing another person's ideas.

In the present study, four experiments studied recall of lists of categorized words. Such recall clearly depends on organized retrieval, and all experiments showed that such recall is ordinarily disrupted in collaborative groups. A turn-taking procedure was used within the groups, rather than the free-for-all procedure used in a similar study.

Basden et al suggest that when you're asked to think of ideas, you formulate a particular retrieval strategy. However, as soon as someone else makes a suggestion, there is a tendency to abandon your own retrieval strategy in favor of one more consistent with the other person's. In a group this is particularly difficult since everyone's strategy is likely to be different.

It is worth noting that various variables affect the effectiveness of group remembering, depending on whether the group is structured as a free-for-all, or the group members take turns in speaking. If turns are taken, waiting time is an important variable. In a free-for-all, the specificity of the suggestions may be important, this being affected by how well the group members know each other. Another study that used a free-for-all procedure found that recall was better if the collaborating pair were friends₂. They argued that a friend is more likely to provide retrieval cues that are specific to the target information. However, if turns are being taken, such social factors may be less important.

References

1. Diehl, M. & Stroebe, W. 1987. Productivity loss in brainstorming groups: Toward solution of a riddle. Journal of Personality and Social Psychology, 53, 487-509.

Diehl, M. & Stroebe, W. 1991. Productivity loss in idea-generating groups: Tracking down the blocking effect. Journal of Personality and Social Psychology, 61, 392-403.

2. Andersson, J. & Rönnberg, J. 1996. Collaboration and memory: Effects of dyadic retrieval on different memory tasks. Applied Cognitive Psychology, 10, 171-181.