The Evolution of Extremism

This chapter examines the evolution of extremism through four central questions: (a) How might extremism have evolved? (b) What function might extremism serve? (c) Is extremism unique to humans? (d) What role does morality play in extremism? In addressing these questions, the chapter discusses genetic proclivities toward extreme behavior and how these proclivities may manifest in a variety of individual differences. Environmental forces are explored that may have favored the emergence of extremism across evolutionary time, drawing on examples from inter-group conflict, virtue signaling, and the utility of extremism as a commitment device and leadership strategy.