Michael Macy

Goldwin Smith Professor of Arts and Sciences

Michael Macy left the farm in Tennessee where he grew up to attend Harvard, where he received his B.A. and later Ph.D, along with an M.A. from Stanford. He is currently Goldwin Smith Professor of Arts and Sciences and Director of the Social Dynamics Laboratory at Cornell, where he has worked since 1997. With support from the National Science Foundation, the Department of Defense, and Google, his research team has used computational models, online laboratory experiments, and digital traces of device-mediated interaction to explore familiar but enigmatic social patterns, such as circadian rhythms, the emergence and collapse of fads, the spread of self-destructive behaviors, cooperation in social dilemmas, the critical mass in collective action, the spread of high-threshold contagions on small-world networks, the polarization of opinion, segregation of neighborhoods, and assimilation of minority cultures. Recent research uses 509 million Twitter messages to track diurnal and seasonal mood changes in 54 countries, and telephone logs for 12B calls in the UK to measure the economic correlates of network structure. His research has been published in leading journals, including Science, PNAS, American Journal of Sociology, American Sociological Review, and Annual Review of Sociology.


  • Collective action;
  • social control;
  • self-organizing group dynamics;
  • cognitive game theory;
  • social exchange theory;
  • computer simulation;
  • laboratory experiments

Current Research Interests

  • Why liberals drink lattes (with Daniel DellaPosta and Yongren Shi)
  • Using Twitter to study mobilization in Arab Spring (with Jon Kleinberg, Noona Oh, Michael Siemon, Silvana Toska, and Shaomei Wu, supported by NSF)
  • How random perturbations can make social dynamics more predictable (with Milena Tsvetkova)
  • Using social media to study the cultural and economic correlates of network structure (with Patrick Park and Bogdan State, supported by NSF)
  • Whether social media attenuate or reinforce social class boundaries (with David Grusky and Bogdan State)
  • Using an MMOG to study intergroup conflict and cooperation (with Dustin Chertoff and Milena Tsvetkova, supported by NSF)
  • The puzzle of “three degrees of influence” (with Chris Cameron)
  • Using Amazon book purchases to measure political and cultural polarization (with Fedor Dokshin and Yongren Shi)
  • Using online experiments to study the willingness to “pay it forward” (with Milena Tsvetkova, supported by NSF)

Selected Publications & Presentations

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“The great bulk of controls over social behavior are not external but built into the relationships themselves.”— George Homans