While there are many determinants of happiness, whether an individual is happy also depends on whether others in the individual’s social network are happy. Happy people tend to be located in the centre of their local social networks and in large clusters of other happy people. The happiness of an individual is associated with the happiness of people up to three degrees removed in the social network. Happiness, in other words, is not merely a function of individual experience or individual choice but is also a property of groups of people.
Happy people attract happy people.