The Bad Apple: Group Poison

A recent episode of This American Life interviewed Will Felps, a professor who conducted a sociological experiment demonstrating the surprisingly powerful effect of bad apples.

Groups of four college students were organized into teams and given a task to complete some basic management decisions in 45 minutes. To motivate the teams, they're told that whichever team performs best will be awarded $100 per person. What they don't know, however, is that in some of the groups, the fourth member of their team isn't a student. He's an actor hired to play a bad apple, one of these personality types:

1. The Depressive Pessimist will complain that the task that they're doing isn't enjoyable, and make statements doubting the group's ability to succeed.
2. The Jerk will say that other people's ideas are not adequate, but will offer no alternatives himself. He'll say "you guys need to listen to the expert: me."
3. The Slacker will say "whatever", and "I really don't care."

The conventional wisdom in the research on this sort of thing is that none of this should have had much effect on the group at all. Groups are powerful. Group dynamics are powerful. And so groups dominate individuals, not the other way around. There's tons of research, going back decades, demonstrating that people conform to group values and norms.

But Will found the opposite.

Invariably, groups that had the bad apple would perform worse. And this despite the fact that were people in some groups that were very talented, very smart, very likeable. Felps found that the bad apple's behavior had a profound effect -- groups with bad apples performed 30 to 40 percent worse than other groups. On teams with the bad apple, people would argue and fight, they didn't share relevant information, they communicated less.

Even worse, other team members began to take on the bad apple's characteristics. When the bad apple was a jerk, other team members would begin acting like a jerk. When he was a slacker, they began to slack, too. And they wouldn't act this way just in response to the bad apple. They'd act this way to each other, in sort of a spillover effect.

What they found, in short, is that the worst team member is the best predictor of how any team performs. It doesn't seem to matter how great the best member is, or what the average member of the group is like. It all comes down to what your worst team member is like. The teams with the worst person performed the poorest.