Interview: Steven Hayes. Steven Hayes is Nevada Foundation Professor in the Behavior Analysis program at the Department of Psychology at the University of Nevada. He’s extraordinarily prolific—author of 44 books and nearly 600 scientific articles—and his career has focused on understanding human language and cognition and the alleviation of human suffering. He developed the Relational Frame Theory, an account of human higher cognition, and has guided its extension to Acceptance and Commitment Therapy (ACT), a popular evidence-based form of psychotherapy…