The results were unambiguous. The men in twenty-three of the twenty-four groups produced more ideas when they worked on their own than when they worked as a group. They also produced ideas of equal or higher quality when working individually. And the advertising executives were no better at group work than the presumably introverted research scientists. Since then, some forty years of research has reached the same startling conclusion. Studies have shown that performance gets worse as group size increases: groups of nine generate fewer and poorer ideas compared to groups of six, which do worse than groups of four. The “evidence from science suggests that business people must be insane to use brainstorming groups,” writes the organizational psychologist Adrian Furnham. “If you have talented and motivated people, they should be encouraged to work alone when creativity or efficiency is the highest priority.”
There is one interesting exception — online brainstorming:
Groups brainstorming electronically, when properly managed, not only do better than individuals, research shows; the larger the group, the better it performs. The same is true of academic research— professors who work together electronically, from different physical locations, tend to produce research that is more influential than those either working alone or collaborating face-to-face.