According to Nicholas Christakis and James Fowler staying healthy and happy isn’t just down to genes, diet and exercise, but is also a product of your social proximity to people who already exhibit those traits.
Their theory is this: good behaviour — like quitting smoking, staying fit or being happy — passes from friend to friend just like a contagious virus.
Unfortunately the same is true of bad behaviour — with clusters of friends “infecting” each other with obesity, unhappiness and smoking –
This article explains the shocking implications.
In This TED talk Nicholas Christakis tracks how a wide variety of traits — from happiness to obesity — can spread from person to person, showing how your location in the network might impact your life in ways you don’t even know.