Dynamic spread of happiness in a large social network: longitudinal analysis over 20 years in the Framingham Heart Study

TLDR

The study used longitudinal social network analysis of 4,739 Framingham Heart Study participants from 1983 to 2003, measuring happiness with a validated four‑item scale, to evaluate whether happiness spreads between individuals and whether distinct happiness niches form within the network. The analysis showed that happiness spreads through the network, with individuals surrounded by happy peers or occupying central positions becoming more likely to be happy, and that proximity to a happy friend within a mile raises happiness probability by 25%, similar effects observed for spouses, siblings, and neighbors, while no effect was seen among coworkers and the influence waned over time and distance, supporting the view of happiness as a collective phenomenon.

Abstract

To evaluate whether happiness can spread from person to person and whether niches of happiness form within social networks.Longitudinal social network analysis.Framingham Heart Study social network.4739 individuals followed from 1983 to 2003.Happiness measured with validated four item scale; broad array of attributes of social networks and diverse social ties.Clusters of happy and unhappy people are visible in the network, and the relationship between people's happiness extends up to three degrees of separation (for example, to the friends of one's friends' friends). People who are surrounded by many happy people and those who are central in the network are more likely to become happy in the future. Longitudinal statistical models suggest that clusters of happiness result from the spread of happiness and not just a tendency for people to associate with similar individuals. A friend who lives within a mile (about 1.6 km) and who becomes happy increases the probability that a person is happy by 25% (95% confidence interval 1% to 57%). Similar effects are seen in coresident spouses (8%, 0.2% to 16%), siblings who live within a mile (14%, 1% to 28%), and next door neighbours (34%, 7% to 70%). Effects are not seen between coworkers. The effect decays with time and with geographical separation.People's happiness depends on the happiness of others with whom they are connected. This provides further justification for seeing happiness, like health, as a collective phenomenon.