Nicholas Christakis ’84 has returned to Yale to study networks. After 12 years as a professor at Harvard, Christakis moved to Yale this fall to work with computer science professor, Daniel Spielman ’92, on the new Institute for Network Science — which integrates a range of social, natural and physical sciences to study the way that individual parts form a more complex whole. Christakis spoke with the News to discuss goals for the upcoming year, his transition to Yale and how discoveries in the Institute could make the world a better place.

Q. What exactly is network science?

A. Network science is about how we can understand how parts interact. And, in interacting, how they create new natural phenomena that were not present just in the parts themselves. So it’s a big intellectual project. It’s a big project across the sciences that in a way is kind of a response to the Cartesian projects in the sciences, itemizing, breaking things down into parts to understand the whole. Here, we’re saying, “No, to understand the whole, you have to figure out how the parts interact with each other.” So I think that’s one of the meta reasons that network science is so interesting and important.

Q. Could you speak to the goals of the Yale Institute of Network Science?

A. The mission of the center is to discover new knowledge, to invent new techniques, to disseminate these techniques and to teach students about them. The work of network science is very interdisciplinary, so we have social scientists and computational scientists and engineers and biologists and lots of people drawn from throughout the University who are interested in networks. They could be neuronal networks or social networks or computer networks or gene networks or protein networks. And all of these networks can be studied and understood in many ways with similar sets of tools. And ideas from one field can fertilize ideas in others, so one of the visions of the Institute is to provide a kind of venue for this cross-fertilization to occur.

Q. Could you speak to the types of research that are being conducted in the Institute?

A. I think it is important to ask the “so what” question. So what if we can understand networks, what can we do with this knowledge to make the world better? So in the social sphere, for example, if you understand how networks work, you could begin to think about how to change behavior of populations more effectively. For example, let’s say you can map networks in the developing world’s villages and understand the social interactions in the village. Maybe you could figure out who to target within the village to make the whole village change its mind about a public health intervention, like a clean water intervention, or a child health intervention, or a vaccination intervention. So we have some opportunities for students to work in Uganda and in Honduras.

Q. Could you explain your role as co-director?

A. Our role is to try to advance the vision of the center and to facilitate discoveries and dissemination of knowledge in this area. Dan and I are supposed to keep the trains running on time. But that’s not the exciting part… In my own lab, the human nature lab, we are focused on three projects right now. One is an exploration of the evolutionary biology and genetics of human social networks and human social interactions. The second is on randomized control trials in the developing world, so how we can intervene in networks to make the world better. And the third project is in terms of experiments on online networks, where we try to experiment with and manipulate the rules of interactions between individuals and in so doing make individuals and groups more cooperative, more innovative or more healthy.

Q. How did you decide to make the move to Yale?

A. I think Yale was going more in my direction at the intersection of the social and natural sciences. I think developments of the interdisciplinary sciences at Yale were very exciting to me, and I was very taken with the way that Yale could newly maneuver in the boundaries between disciplines. This was very exciting to me and was the main thing that got me to move. I am an alumnus of [Yale College] so of course I felt close to the place.