Researchers have gone to a great deal of trouble to test the efficacy of group brainstorming. In a typical experiment, participants arrive in a group. Half of them are randomly chosen to be in the ‘work as a group’ condition and are placed in one room. They are given standard brainstorming rules and have to come up with ideas to help solve a specific problem (perhaps design a new ad campaign, or find ways of easing traffic congestion). The other half of the participants are asked to sit alone in separate rooms, are given exactly the same instructions and tasks and asked to generate ideas on their own. Researchers then tally the quantity of ideas produced under the different conditions, and then experts rate their quality. So do such studies show that group brainstorming is more effective than individuals working alone? Many scientists are far from convinced. Brian Mullen from the University of Kent at Canterbury and his colleagues analysed the efficacy of group brainstorming in this way, and were amazed to discover i the vast majority of experiments, the participants working on their own produced a higher quantity and quality of ideas than those working in groups.