By Dr. Mallika Marshall

BOSTON (CBS) – For centuries, humans have been shaking hands as a form of greeting. Many years ago, historians believe a handshake was a way for people to show that they were unarmed and therefore did not pose a threat.

But researchers at Harvard Business School wanted to find out whether shaking hands serves an important purpose in modern society.

They studied people engaging in car buying negotiations and found that when people shook hands beforehand, they tended to have a more cooperative spirit, were found to be more honest and warm during the talks, and in the end, both parties benefited. If there was no handshake, the results were not as positive.

Researchers conclude that it usually in everyone’s best interest to shake hands to show a cooperative spirit. Now they want to see whether hugs, high-fives, or fist pumps promote the same amount of cooperation.

Dr. Mallika Marshall