When it comes to the mental world, when we design things like health care and retirement and stock markets, we somehow forget the idea that we are limited. I think that if we understood our cognitive limitations in the same way that we understand our physical limitations … we could design a better world.

Ariely is arguing from the core premise of behavioral economics: people are not consistently rational, and our decision-making is bounded by predictable cognitive limits (biases, inattention, present bias, framing effects). Yet major institutions—retirement systems, health insurance choices, and financial markets—are often designed as if individuals can process complex information and optimize long-term outcomes unaided. The quote advocates “choice architecture” and policy design that treats mental limitations like physical ones: not as moral failings, but as constraints to accommodate. If designers anticipate systematic error, they can build defaults, simplification, and safeguards that reduce harm and help people achieve their own goals more reliably.