Leda Cosmides is an American cognitive psychologist known for her work in evolutionary psychology. She is a professor at the University of California, Santa Barbara and co-director of the Center for Evolutionary Psychology. Cosmides is recognized for her research on the human mind and how it has been shaped by evolutionary processes. Cosmides gained prominence for developing the Wason selection task, which explores how people reason about social contracts. Her work emphasizes the importance of understanding cognitive processes in the context of evolutionary theory, contributing significantly to the fields of psychology and cognitive science.