The right answer is obviously B.

Why do decisions go wrong? Many times, it’s because the decision is made by a group, not by an individual. Individuals tend to look at the evidence and make a decision. It may not be the right decision but it’s often based on an assessment of the facts.

Groups may assess the facts as well but they also assess the politics of the situation. The issue may be decided on group dynamics rather than a dispassionate review of the evidence.

Bain & Company recently published a white paper (Decision Insights: How Group Dynamics Affect Decisions) that provides a useful summary of the issues. Here are four ways, for instance, that group dynamics can lead to debacles.

Conformity – if you’re a team player, you may go with the team’s decision even if you realize it’s wrong. The graphic above shows Solomon Asch’s classic experiment. Which line – A, B, or C – is the same length as the line to the left? Working alone, you’ll probably figure out that C is the right answer. However, if you’re in a group that says B is the right answer, you’re quite likely to go with the group. Many companies say they want team players, but they need to be aware of the implications. (See also Group Behavior – The Risky Shift.)

Group Polarization – let’s assume for a moment that you belong to a politically conservative group. You talk to conservatives regularly. Indeed, you talk only to conservatives. You reinforce each other and the group gets more and more conservative. In many cases, the group becomes more conservative than any of its individual members. (See also, Will The Internet Cause Dementia? and Where You Stand Depends on Where You Sit.)

Obedience to Authority – the quickest way to stifle innovation is to let the boss speak first. We all want to please our bosses, so if the boss expresses a preference for X over Y, we often begin to find reasons why X is indeed better than Y. It’s hard to argue with your boss … unless you’re specifically asked to play the role of devil’s advocate, which is often a good idea. Note to bosses: keep quiet. (See also, Want A Good Decision? Go To Trial.)

Bystander Effect – when we’re not sure what to do, we often look to others to see what they’re doing. If they’re panicking, we get panicky. If they’re cool, calm, and collected, we calm down (even if we think we should panic). Individuals often understand a situation better than groups do which is why you should never have a heart attack in a crowd.

So, what to do? Diversity in a group often helps overcome groupthink and polarization, so pull people together from different backgrounds and risk profiles. Playing roles can help. You might stage a mock trial or ask someone to play the devil’s advocate. You can also ask each individual to write down his or her recommendation anonymously, put them all in a hat, and then discuss all of them. You can also prime the team by discussing what it means to be a team player. Emphasize the need to make the best decision, not just the most comfortable one.

And, if all else fails, just ask the boss to leave the room.