Feeling inexplicably cheery today? Thank your friends. And your friendsí friends. And your friendsí friendsí friends.

New research shows that happiness isnít just an individual phenomenon; we can catch happiness from friends and family members like an emotional virus. When just one person in a group becomes happy, researchers were able to measure a three-degree spread of that personís cheer. In other words, our moods can brighten thanks to someone we havenít even met.

Your happiness could be contagious - Behavior- msnbc.com