You might think that the more bright people in a room, the better the chance they have of solving a problem. But a new paper coauthored by MIT researchers asserts that a group’s performance hinges more on how well its members coöperate—and often, that depends on the proportion of women in the group.

“We did not know if groups would show a general cognitive ability across tasks,” says Sloan professor Thomas W. Malone, one of the authors of the paper, which was published in the journal Science and describes two recent studies. “But we found that there is a general effectiveness, a group collective intelligence, which predicts a group’s performance in a lot of situations.”

That effectiveness, the researchers believe, stems from a group’s “social sensitivity,” or willingness to let all its members take turns and apply their skills to a given challenge. Groups in which one person dominated didn’t do as well on group tasks as those in which “the conversational turns were more evenly distributed,” says Malone. Teams containing more women had more extensive participation from their members than teams containing fewer women.

In the studies, 699 people, placed in groups of two to five, worked on tasks including visual puzzles, negotiations, brainstorming, games, and design assignments. The researchers concluded that group dynamics accounted for about 30 to 40 percent of the variation in performance. Many participants performed similar tasks individually; those results did not significantly predict the performance of their groups.

In addition to Malone, the paper’s authors included Anita Williams Woolley of Carnegie Mellon University; Christopher F. Chabris of Union College in New York; Media Lab professor Alex Pentland, PhD ‘82; and Nada Hashmi, SM ‘08, a doctoral candidate at Sloan. To record group conversations and interactions, the researchers equipped individuals with wearable electronic badges designed by Pentland’s Media Lab group. The badges provided a complete record of each group’s conversational patterns and revealed its propensity to take turns.

Only when analyzing the data did the coauthors begin to suspect that the number of women in a group had predictive power. The gender effect “was a surprise to us,” says Malone, who adds that this finding should be regarded as merely a generalization. “Of course some males have more social skill or social sensitivity than females,” he says. “People with social skills are good for a group—whether they are male or female.”

Malone believes that the findings could help organizations get groups to function better. For now, the researchers plan further work on the precise nature of group interactions, and possibly on the gender issue. “Having a bunch of smart people in a group doesn’t necessarily make the group smart,” he says.