Nicholas A. Christakis, MD, PhD, MPH, is a social scientist and physician at Yale University who conducts research in the fields of network science, biosocial science, and various other fields. His current work focuses on how human biology and health affect, and are affected by, social interactions and social networks. He directs the Human Nature Lab and is the Co-Director of the Yale Institute for Network Science. He is the Sterling Professor of Social and Natural Science, appointed in the Departments of Sociology; Statistics and Data Science; Ecology and Evolutionary Biology; Biomedical Engineering; Medicine; and the School of Management.

Dr. Christakis received his BS from Yale in 1984, his MD from Harvard Medical School and his MPH from the Harvard School of Public Health in 1989, and his PhD from the University of Pennsylvania in 1995. He was elected to the National Academy of Medicine in 2006; the American Association for the Advancement of Science in 2010; the American Academy of Arts and Sciences in 2017; and the National Academy of Sciences in 2024.

One line of work in his lab focuses on how health and health behavior in one person can influence analogous outcomes in a person’s social network, via social contagion. This work involves the application of statistical and mathematical models to understand the dynamics of diverse phenomena in longitudinally evolving networks. This work also uses large-scale experiments to examine the spread of knowledge and behaviors (ranging from altruism to breastfeeding, etc.), including in field trials in the developing world directed at improving public health (e.g., in Honduras and India). A second line of work examines the genetic and evolutionary determinants of social network structure, showing that social interactions have been shaped by our genome and shape it, with related projects that have mapped networks of populations in Tanzania and Sudan who live as all humans did 10,000 years ago. This work also involves exploring the spread of the microbiome in human populations and the role of chemosignaling in social interactions. A third line of work has used artificial intelligence (AI) agents (“bots”) to affect social processes in “hybrid systems” of humans and machines.

Dr. Christakis is the author of over 220 articles and several books. His influential 2009 book, Connected: The Surprising Power of Our Social Networks and How They Shape Our Lives, documented how social networks affect our lives and was translated into twenty foreign languages. His 2019 book, Blueprint: The Evolutionary Origins of a Good Society, was a New York Times bestseller and was translated into over ten foreign languages.

In 2009, Christakis was named by Time magazine to their annual list of the 100 most influential people in the world. In 2009 and in 2010, he was listed by Foreign Policy magazine in their annual list of Top 100 Global Thinkers.