Physical Intelligence

October 28, 2019
Grafton, director of UC Santa Barbara’s Brain Imaging Center, explains the “components of the mind that allow anyone to engage with and change the world” in this thoughtful debut. He uses both personal experience—solo hiking and camping adventures in California’s High Sierra region—and medical and scientific case studies to illustrate his points. To explain “body schema,” the map of the body that the brain maintains to control posture and movement, Grafton uses examples of how it can malfunction, such as in people with epilepsy, one of whom reported, just before an attack, feeling “herself become smaller and smaller.” To probe the subject of “self-guidance navigation,” he describes relying on limited external cues to get himself out of a potentially treacherous hiking environment. The book’s concepts aren’t always intuitive, but Grafton does his best to employ understandable examples, such as cooking breakfast as an instance of “hierarchical reinforcement learning,” or fixing his camp stove as an illustration of motor control. This is a well-written introduction to what’s going on when one performs everyday but deeply complex actions, such as walking, which “demonstrates a beautiful calculus that the brain endlessly performs to inform movement.”