"Hugging protects people who are under stress from the increased risk for colds that's usually associated with stress," notes Sheldon Cohen, a professor of psychology at Carnegie.

The expert in positive psychology was hired by the US Army to develop a ‘resilience program’ to help soldiers cope better with the stress of combat.

When Achor lectured about positive psychology at financial firm UBS, he noticed that they had been teaching their employees that stress is bad, which only increased their stress further.