The same applied to happiness: if someone in the room spent the next week elated, that joy would probably become infectious. And the same for smoking: if a man in the room finally managed to quit, the chances were good that his friend sitting two rows in front of him would quit as well. And then, a short while later, a friend of his friend whom he didn’t know would do the same thing.
The lecture was given by Dr Nicholas Christakis, a professor from Harvard who had flown over to expand on theories that he once thought of as ‘cockamamie’. His talk examined the power of social networks to influence our behaviour, and suggested that our actions were only partly determined by our own free will. Increasingly, something he called ‘social contagion’ seemed to be getting the upper hand.
Some of Dr Christakis’s theories seemed obvious — the chances of becoming obese because we hang around with obese friends who like eating cake — but some are more surprising, including his findings that we may become obese just by knowing someone who knows someone who is fat.
One person at the lecture, who’s not obese, was Dr Ben Goldacre, author of ‘Bad Science’, the bestselling exposure of quackery and lazy research. He kept his mouth shut during the talk, which was not necessarily a sign of approval, but probably indicated a certain level of intrigue in what was being delivered.
Dr Christakis, who is 47 and has grey hair and a gregarious outlook, describes himself “both as someone who craves solitude, but also as someone who is energised by the contact with friends and family; my wife thinks I am an extrovert, and I guess I am”. Recently he has become a bit of a media star in the United States, not least upon the publication of his book ‘Connected’ (written with his colleague James Fowler, a professor of political science at the University of California at San Diego).
‘Connected’ is one of those popular social science books, like ‘The Tipping Point’ or ‘Freakonomics’, that attempts to explain how we live and how the herding instinct of the crowd influences our actions. It has not yet sold quite as well as the others, although its contents seem to have featured on almost every talk show in the United States as well as the cover of the ‘New York Times Magazine’. Last year ‘Time’ magazine named Dr Christakis in its list of the 100 most influential people in the world.
Emotional stampedes
‘Connected’, which is published in the UK next month, makes many claims, and many startling observations. Christakis sums them up thus: “People affect each other even in things (like body size or emotional states) that many readers would not necessarily expect.” He calls these things “emotional stampedes” and “a social chain reaction”. The authors believe that at least some part of this is deeply embedded in our genetic heritage, which is, as Christakis points out, “a non-trivial finding”.
Dr Christakis is nothing if not an entertainer, and ‘Connected’ is nothing if not diverting. It is not all about getting plump and happy; it is also about sex and making money. At Nuffield, Christakis tells the story of a friend of his, Brian Uzzi, who has used the impact of social networks to analyse the success or otherwise of Broadway musicals. “He finds that if the key players — the director, costume designer, sound person, producer, etc — all worked together before, and everyone knows everyone else, then the show is a flop. He also finds that if you put together a group of people, who have never worked together before, the show is also a flop. But if you put together a group of people some of whom have worked together and some who haven’t, then the show is a runaway critical success with enormous financial rewards.”
He had told me the same story when we had met a few hours before for a chat in the Nuffield College common room. He picked up his book repeatedly as he spoke, pointing to the coloured diagrams that show the distribution of obesity, happiness, sexual activity and smoking among groups of hundreds or thousands of people. Clusters of red, green and blue nodes spread out seemingly randomly towards the edges of their pages. But they are not random; they are connected and to some extent predetermined, and they are the cause of zealous excitement.
These networks can harbour a flow of generally undesirable things — violence, germs, sexually transmitted diseases, suicide, unhappiness. But good things also flow — happiness, love, altruism, valuable information on how to find a job.
Christakis’s work is new in its scope and ingenuity, but his interest in human interaction has many forebears, stretching back at least as far as Aristotle. Academic interest in the impact of social networks goes back at least a century, to the work of Georg Simmel, the German sociologist who became interested in triads, extending the study of relationships between two people to three.
