Yphtach Lelkes

Yphtach Lelkes, Ph.D.

Yphtach Lelkes
  • Associate Professor of Communication
  • Co-Director, Polarization Research Lab
  • Co-Director, Center for Information Networks and Democracy

Yph Lelkes studies the structure, dynamics, and causes of political attitudes, with a particular emphasis in polarization and American politics. His work lies at the intersection of public opinion, political psychology, and political communication.

Yphtach (Yph) Lelkes is an Associate Professor at the Annenberg School for Communication. He studies public opinion, political psychology, and political communication.

His interests lie at the intersection of political communication, public opinion, and political psychology. In the broadest sense, he is interested in the antecedents, structure, and consequences of citizens’ political attitudes. He has focused on three, often overlapping, research questions: (1) What are the roots, structure, and consequences of affective polarization? (2) What is the impact of changes to the information environment on political attitudes? (3) What are the psychological underpinning and structure of political belief systems?

His work appears in top field journals in Communication (Journal of CommunicationJournal of Computer Mediated Communication), Political Science (American Journal of Political ScienceJournal of Politics), Psychology (Journal of Personality and Social Psychology), as well as general interest journals (PNASNature Human Behavior). 

He takes a problem- rather than methods-based approach to social science. As such, he regularly employ traditional methods (such as surveys, lab & field experiments, and quasi-experiments) as well as more computationally intensive methods (using, e.g., geographic data, huge administrative datasets, and automated text analysis).

He is the Co-Director of the Polarization Research Lab, which looks at affective polarization, social trust, and political violence. He is also the Co-Director of the Center for Information Networks and Democracy, which researches the benefits and risks that information networks have for democracy.

Before joining the University of Pennsylvania, he was faculty at the Amsterdam School of Communication. He received his Ph.D. from Stanford University.

Lelkes is a faculty affiliate at the Institute for the Study of Citizens and Politics and a fellow at the Amsterdam School of Communication Research. He also holds a secondary appointment in the Penn Political Science department.


  • B.A., University of Wisconsin-Madison, 2005
  • M.A., Temple University, 2008
  • Ph.D., Stanford University, 2012

Selected Publications