The illusion of group effectivity is the persistent and widespread belief, despite some evidence to the contrary, that group performance is superior to individual performance. The popular media [Page 423]and quasi-scientific press often express strong and optimistic beliefs regarding the effectiveness of group-based work, and these beliefs seem widely shared within society. Sometimes, however, the scientific literature clearly shows that groups do not perform well at all and that certain tasks might be better left to individuals. The illusion of the superiority of the group over the individual may persist even when the individual has had extensive experience with a particular task, and therefore, it is not just due to cultural beliefs that are easily falsified through experience.

The illusion of group effectivity has been studied ...