An article on the Freakonomics blog repudiates the notion that happiness is contagious. While an increase in your friend’s happiness statistically significantly increases your happiness level, Justin Wolfers contends that the cause is the shared emotional experiences and environments that friends share.

There is no good way to differentiate in the data whether an individual’s increase in happiness is due to his friend’s increase in happiness or to some shared external event that increased both your happiness levels (e.g.; your favorite baseball team just won the World Series).

However, now that I think about it, Justin Wolfer’s explanation seems more probable. Amusingly in the same British Medical Journal where the James Fowler and Nicholas Christakis released their happiness is contagious article, Ethan Cohen-Cole and Jason Fletcher setup an experiment which “proved” that height, headaches and acne are contagious in order to prove that silly experimental setups lead to silly conclusions 🙂

Read the article at:
http://freakonomics.blogs.nytimes.com/2008/12/09/is-happiness-contagious/?emc=eta1