PERSON
Cass Sunstein
American legal scholar and behavioral economist (b. 1954) whose framework of
libertarian paternalism and
nudging shows that every choice environment steers behavior—and that the question is never whether to steer but in which direction, toward what end, and for whose benefit.
The husband who vanished into Claude Code while his wife wrote a Substack post about his disappearance was not lacking information about his own behavior. He knew he had been working for fourteen hours. He knew he had not eaten. He could not stop. This is not a failure of will but a fact about choice architecture: the structure of the environment in which decisions are made shapes those decisions with a power that dwarfs the power of information, rational deliberation, or exhortation. Cass Sunstein built his career on this fact, developing with Richard Thaler at the University of Chicago the framework of
libertarian paternalism—the position that
choice architectures can legitimately steer people toward better outcomes while preserving their freedom to choose otherwise. The
nudge is any feature of choice architecture that alters behavior in a predictable way without forbidding any option or significantly changing economic incentives. The cafeteria that puts salads at eye