Network in Social Sciences

Today we had a very great theory lunch. Everybody loves it. The speaker, Nicholas Christakis, an MD, is excellent.

It is about the network study in social sciences. Geez, now I know medical social sciences are so interesting. No wonder there are many MDs jumping on this wagon.

Network is a hot term in Systems Biology. Indeed, in biology, numerous methods and modeling was invented for solving biological network questions. Social scientists take advantage on these tools and apply them on their own network study in social sciences. Nick had many famous publications by this approach. Actually, one of them was mentioned by me here in a jerky way, yes, the paper finding that fat people make friends fat.

Nick tracked the records of a small town named Framingham for over 32 years, and employed network modeling technique to monitor the changes of the network structure and individual person (node). He found fat people were clustered non-randomly. And surprisingly obesity could actually spread in the network. The "spread of obesity" is not limited to geographical distance, but only works within same gender, some very interesting findings.

Similar approach was applied on smoking/quit-smoking studies. Smokers are usually clustered together in the network but surprisingly it showed usually all nodes in a clusters are gone at the same time. It might suggest it is more efficient to quit smoking by groups, but not individual.

Most interestingly, same approach was used on happiness studies. This is a very hot topic now. Above all, the goal of a government is to make people happier. The primary results indicated money does play certain role on it, but not very significantly (surprisingly?)

The networks in social sciences and in biology are very different. It could be cool if someday same ideas in social science network studies get burrowed again by biologists, although I cannot see it will happen in a near future...

Related reports can be found at
http://www.hcp.med.harvard.edu/node/1378 and
http://harvardscience.harvard.edu/directory/researchers/nicholas-christakis
http://www.wjh.harvard.edu/soc/faculty/christakis/

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THEORY LUNCH
FRIDAY, APRIL 25
WAB 563 12PM

Nicholas Christakis

Department of Health Care Policy
Harvard Medical School & Department of Sociology
Harvard Faculty of Arts and Sciences

The spread of health phenomena in complex, longitudinally resolved social networks


Abstract
Our work has involved the quantitative investigation of whether and how various health-related phenomena might spread from person to person in complex networks. We have developed various data sets to support these investigations, including a densely interconnected, longitudinally resolved network of 12,067 people assessed repeatedly from 1971 to the present. Each node in this network has an average of 11 ties of various kinds, including friends, siblings, spouses, offspring, coworkers, and neighbors. We observe discernible clusters of individuals with various traits, including obesity, smoking, eating, medication taking, and happiness, and we document that these clusters are not solely due to selective formation of social ties between nodes. Rather, processes of social contagion are also apparent within the network. Various aspects of our findings suggest that the spread of social norms is a key mechanism underlying these inter-personal health effects. In other work, we have examined the genetic basis for social network formation and have developed a novel model for the social processes involved (the "attract and introduce" model). The recognition of the role of supra-individual, network effects on individual health lays a further foundation for public health by providing a rationale for the claim that health is not just an individual, but also a collective, phenomenon