Everyone knows that “teamwork” is important to success, but it’s only been recently that scientists have “cracked the code” of what makes a team successful.

The newly published Team Genius: The New Science of High-Performing Organizations, authors Rich Karlgaard and Michael S. Malone reveals research showing that:

1. The ideal team size is between 5 and 9.

Contrary to the generally-accepted assumption that management can fix a problem by throwing people at it, adding team members beyond that point decreases the likelihood of success.

2. “Good chemistry” makes teams less effective.

If there’s not enough diversity to create conflict, teams tend to fill into predictable ruts. What’s important here isn’t the appearance of diversity (i.e. quotas), but diversity of culture and ways of thinking.

3. Bonding with a team releases oxytocin.

That’s the same brain chemical that’s released (in much greater quantities of course) during a sexual orgasm. The takeaway here is that people enjoy work more when they’re on a good team.

4. The most effective teams don’t have leaders.

Teams work best when members listen and talk in equal measure. If one member takes control and begins to dominate the discussions, it creates resentment. The team falters.

5. Effective teams do need managers, though.

Diverse teams are more creative and get more done but they require a team manager (not an individual contributor) whose full time job is to help team members communicate and work together, despite their diversity.

6. Small teams outperform solo geniuses.

While Einsteins and Newtons do exist, they’re exceedingly rare. In real life, brilliant people are more effective and creative when working with others, especially those who are equally brilliant.

7. Conflict within a team is essential.

A certain amount of “creative abrasion” allows a team to identify alternative approaches. However, everyone must agree that conflicts won’t get personal and promise to surface the reasons behind their disagreements.

8. Men are insecure when in the minority.

Men feel dissatisfied and less committed to a project when assigned to a team consisting of more women than men. Women, however, are apparently unaffected by this ratio.

9. Mixed-age teams outperform youth-only teams.

Despite the stereotype that youthful energy trumps all, practical business experience turns out to be a useful thing to have on a team. However, mixed-age teams have more “creative abrasion” and thus require more active management.

10. Virtual teams are vastly overrated.

Even with all the technology available today, teams work better together and get more done when members are in close physical proximity. If a team must be virtual, it should have periodic in-person team meetings.