Effects of Group Size on Problem Solving

Study Suggests Small Groups Solve Problems Better

Small group solving a problem
PeopleImages.com / Digital Vision / Getty Images


  • A study published in the Journal of Personality and Social Psychology looked at the effects of group size on problem solving.
  • Researchers compared the problem-solving performance of small groups to that of individuals working alone. 
  • The results of the study indicate that groups of three solve problems better than even the best individuals working alone.
  • What are the implications of these results? The findings may be useful in academics, where problem solving groups might serve as an effective learning tool. Groups and teams in science, health care, and business may also find these techniques useful as well.

Are Groups Better at Solving Problems?

Are individuals or groups better at solving problems? According to one study, groups of three to five people perform better than individuals when solving complex problems. The research, published in the Journal of Personality and Social Psychology, suggests that groups of three people are able to solve difficult problems better than even the best individuals working alone.


Researchers had 760 student participants from the University of Illinois at Urbana- Champaign solve letters-to-numbers code problems, working either individually or as part of a group. The study notes that there is a surprisingly small amount of research on the effect of group size on problem solving. Earlier research suggested that groups perform better than individuals on problems of average difficulty. The current study assessed performance by comparing the number of trials needed to solve the problem as well as the number of errors made. The results demonstrated that groups of sizes three, four, and five performed better than individuals at solving the problems.

In a press release from the American Psychological Association, lead researcher Patrick Laughlin attributed the improved performance of groups to "the ability of people to work together to generate and adopt correct responses, reject erroneous responses, and effectively process information."

The study also ascribed the success of small groups on letters-to-numbers tasks to "the group members combined their abilities and resources to perform better than the best of an equivalent number of individuals on the highly intellective complementary group task."

While researchers had hypothesized that groups of two would outperform an equivalent number of individuals, the results of the study actually demonstrated that groups of two people performed at the same level as individuals working alone. Also, while groups of three, four and five people performed significantly better than an equivalent number of "best individual" and two-person groups, these three groups did not differ from each other in terms of performance. The results of this study therefore suggest "three group members were necessary and sufficient for the groups to perform better than the best of an equivalent number of independent individuals."

Implications of the Research

This study has a number of implications in academics, science, medicine, and business. The results indicate that groups of three are more efficient and more accurate at solving moderately difficult problems that require the use of logic, verbal, and qualitative understanding. The authors of the current study suggest further research is necessary to determine if three-person groups are more effective at solving other types of problems and whether effective problem-solving within a group then transfers to individual problem solving.

Further Reading on Group Problem Solving

Bonner, B. L. (2004). Expertise in group problem solving: Recognition, social combination, and performance. Group Dynamics: Theory, Research,and Practice, 4, 277-290.

Bray, R. M., Kerr, N. L., & Atkin, R. S. (1978). Effects of group size, problem difficulty, and sex on group performance and member reactions. Journal of Personality and Social Psychology, 36, 1224-1240.

Hill, G. W. (1982). Group versus individual performance: Are N _ 1 heads better than one? Psychological Bulletin, 91, 517-539.

Tindale, R. S., & Kameda, T. (2000). “Social sharedness” as a unifying theme for information processing in groups. Group Processes and Intergroup Relations, 3, 123-140.

More About Problem-Solving:

View Article Sources
  • References:
  • Laughlin, P., Hatch, E., Silver, J., & Boh, L. (2006) Groups Perform Better Than the Best Individuals on Letters-to-Numbers Problems: Effects of Group Size, Journal of Personality and Social Psychology, Vol. 90, No. 4.
  • American Psychological Association. (2006) Groups Perform Better Than the Best Individuals at Solving Complex Problems, APA Press Release.