Instead, the smartest teams were distinguished by three characteristics.First, their members contributed more equally to the team’s discussions, rather than letting one or two people dominate the group.Second, their members scored higher on a test called Reading the Mind in the Eyes, which measures how well people can read complex emotional states from images of faces with only the eyes visible. Finally, teams with more women outperformed teams with more men. 

The smartest teams had more equal contributions, more ability to read each other, and more women.

All three of these qualities are related.