Twelve-member juries may be too big to reach a true consensus, say Scottish psychologists. Their research shows that in groups larger than about seven, discussion tends to be dominated by a few individuals.
鈥淚n a group of ten, typically two people won鈥檛 open their mouths,鈥� says Simon Garrod of Glasgow University, who led the study. 鈥淭hree people could really drive a decision through.鈥� This may help to explain why larger groups of people have more trouble reaching a consensus.
Garrod based his findings on a study of 150 people, who read an article on student plagiarism and discussed their opinions in groups of five or ten.
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He believes his research has important implications for many group decision-making situations in business or government, as well as in court.
Small cliques
The study鈥檚 participants read an article about student plagiarism and Garrod鈥檚 team gauged their immediate opinions with a questionnaire. They then discussed what they had read in groups of either five or ten before giving their opinions again.
In the smaller groups, all five people tended to contribute to a consensual decision. Speakers often interrupted each other, allowing everyone to have their say.
鈥淚n a small group, other people can finish or modify what you鈥檙e saying,鈥� says Garrod. This allows a final decision to emerge from an amalgamation of everyone鈥檚 opinions.
Larger groups, on the other hand, were dominated by small cliques who did all the talking. Interruptions were infrequent and the discussion turned into a sequence of monologues.
More effective
The different style of discussion also affected the participants鈥� final decisions. In the smaller group, peoples鈥� opinions tended to be dominated by those of other people they had interacted with most 鈥� those they had preceded or followed most often in the discussion. Conversely, in the larger groups, people were more influenced by the opinions of the dominant group members.
Garrod is currently investigating ways of making discussion in large groups more interactive by using 鈥榝acilitators鈥�. These people do not offer opinions on the issues under discussion, but ensure that everyone has their say.
They also force the group to resolve differences by stopping them from skirting around disagreements. Garrod suggests that facilitators could make juries more effective.
Garrod presented his research at the British Association鈥檚 Festival of Science in Glasgow.