LONDON, Dec 4: Happiness is infectious and can “ripple” through social groups such as family and friends — but work colleagues are apparently immune to each other’s moods, according to a study published on Friday.

The effect creates “clusters” of happy and unhappy people, both socially and in geographical terms, said the study, stressing that contentment “is not merely the province of isolated individuals.”

But while the mood of neighbours and friends can have more impact on people than that of live-in partners, work colleagues are not affected by a happy person in their midst, said the study in the British Medical Journal.

“Changes in individual happiness can ripple through social networks and generate large scale structure in the network, giving rise to clusters of happy and unhappy individuals,” said the study’s authors.

“Most important from our perspective is the recognition that people are embedded in social networks and that the health and well-being of one person affects the health and well-being of others.

“Human happiness is not merely the province of isolated individuals,” added the study, by Professor Nicholas Christakis of Harvard Medical School and Professor James Fowler of the University of California, San Diego.

According to the study, geography can affect happiness: if you have a friend who becomes happy and lives within a mile, it will increase your likelihood of being happy by 25 per cent.

They found that live-in partners who become happy increase the likelihood of their partner being happy by 8 per cent; happy siblings living nearby boost joy levels by 14 per cent, and neighbours by 34 per cent.

“Work colleagues did not affect happiness levels, suggesting that social context may curtail the spread of emotional states,” said the study.

In an editorial accompanying the study, Prof Andrew Steptoe of University College, London and Prof Ana Diez Roux of the University of Michigan School of Public Health, called it “groundbreaking.”

“If happiness is indeed transmitted through social connections, it could indirectly contribute to the social transmission of health, and has serious implications for the design of policies and interventions,” they said.

The study was based on research involving 5,124 adults aged 21-70, followed between 1971 and 2003.

To assess happiness they were asked to agree or disagree with four statements: “I felt hopeful about the future,” “I was happy,” “I enjoyed life,” “I felt that I was just as good as other people.” Happiness was defined as a maximum positive agreement with all four statements.—AFP