Multiple brains work well when the answer is a simple numerical figure or fact, and the question is not coming from the collective intelligence themselves. It helps when the input mechanism posing the problem to the collective intelligence has strict quality control.

While looking for solutions and answers, we find that an individual provides a different answer than a group of people. Wisdom of the crowd is often considered better, as an individual might be biased, manipulated or have some ulterior motive. Depending on the problem, the wisdom of the c...

Scientific communities make good use of the peer-review process (individuals checking each other) to achieve quality on the basis of a meritocracy.