David Dobbs quotes from Thomas Seeley’s Honeybee Democracy: 

We will see that the 1.5 kilograms (3 pounds) of bees in a honeybee swarm, just like the 1.5 kilograms (3 pounds) of neurons in a human brain, achieve their collective wisdom by organizing themselves in such a way that even though each individual has limited information and limited intelligence, the group as a whole makes first-rate collective.

His assessment of Seeley's lessons for group decision-making: