The British Medical Journal has published a study showing that happiness is contagious more than was previously imagined. Here’s a quote from an article about the study in the Boston Globe:
Psychologists have long known that feelings can be contagious over short time frames or that people reflexively return smiles. But the new social network analysis showed that that contagious effect extends three “degrees” – as far as a friend of a friend of a friend – and drops off with time and distance.
The effects can last a year, researchers said in British Medical Journal.
“Your happiness is not just about your own choices and actions and behaviors and thoughts,” said Dr. Nicholas Christakis, a coauthor of the study and a professor of medical sociology at Harvard Medical School. “It’s like there are emotional stampedes that ripple across this infinite fabric of humanity.”… A happy friend who lives within a mile, for example, boosts your odds of being happy by 25 percent, researchers found.
So, there’s some scientific proof that you can actually spread good cheer and that it ripples beyond the stranger you smiled at to even their friends and families. Your kindness to others is not in vain.