Welcome to my website! I am a James S. McDonnell Foundation Postdoctoral Fellow in the Department of Biology at the University of Pennsylvania, where I work with Joshua Plotkin. I obtained my PhD in applied and computational mathematics from Princeton University.

I am an applied mathematician and a theoretical biologist studying cooperation and collective behavior in complex systems. My work integrates tools from evolutionary game theory, dynamical systems, and network science to explore topics including

• the role of peer-to-peer gossip in cooperation;
• the impact of stereotype use on indirect reciprocity;
• cooperation and polarization in group-structured populations;
• emergent hierarchies in adaptive networks; and
• self-organized division of labor in ant colonies.

News: I will be joining the University of Michigan as a postdoctoral fellow (2026-2027) and then as an assistant professor (2027-) in the Department of Mathematics and the Center for the Study of Complex Systems. My group will be recruiting at all levels. If you are interested in working with me, please get in touch at marikawa (at) sas.upenn.edu.