The Joy of Movement: How Exercise Helps Us Find Happiness, Hope, Connection, and Courage

by Kelly McGonigal

In these studies, experimenters deliver electric shocks to rats by attaching an electrode to their tails or through an electrified grid on their cage floor. If you shock rats in an unpredictable and unavoidable manner, you can trigger behaviors that look like depression, anxiety, or post-traumatic stress disorder. The rats become less interested in eating or socializing with other rats. They freeze at any unknown noise or sign of threat. And having learned that there is nothing they can do to prevent the shocks, they stop trying to improve their situation in other stressful contexts—a phenomenon known as learned helplessness. Throw the rats in a bucket of water and they won’t even try to swim, sinking to the bottom in what psychologists call a defeat response. But sometimes shocking rats doesn’t make them helpless; instead, it makes them confident, even courageous. The key to reversing the psychological effect of shocks is to give the rats some element of control. Any element of control. For example, in one setup, a rat is placed in a running wheel with an electrode attached to its tail. The experimenter delivers shocks until the rat turns the wheel. The rat can’t prevent new shocks, but it can shorten their duration. This rat doesn’t become depressed or traumatized; it becomes braver in new environments and more resilient to future stress. Some researchers believe that what gets learned through controllable shocks is a different relationship to fear. What the rat learns i...