Functional groups which work well together, include open sharing of research and ideas, persistence of best output, are dedicated to realism, and are more focussed on problem solving than status display, will be smarter. The group works like a filter which generates multiple solutions and selects, remembers, and abstracts the best.

Dysfunctional groups which do the opposite will be catastrophically stupid.

There have been plenty of dysfunctional groups in history.