The Disordered Mind: What Unusual Brains Tell Us About Ourselves

by Eric R. Kandel

This astonishing result might suggest that we are at the mercy of our unconscious instincts and desires. In fact, however, the activity in our brain precedes the decision to move, not the movement itself. As Libet explains, the process of initiating a voluntary action occurs rapidly in an unconscious part of the brain; however, just before the action is begun, consciousness, which comes into play more slowly, approves or vetoes the action. Thus, in the 150 milliseconds before you lift your finger, your consciousness determines whether or not you will actually move it. What Libet showed is that activity in the brain precedes awareness, just as it precedes any action we take. We therefore have to refine our thinking about the nature of brain activity as it pertains to consciousness. In the 1970s Daniel Kahneman and Amos Tversky began to entertain the idea that intuitive thinking functions as an intermediate step between perception and reasoning. They explored how people make decisions and, in time, realized that unconscious errors of reasoning greatly distort our judgment and influence our behavior.11 Their work became part of the framework for the new field of behavioral economics. Kahneman and Tversky identified certain mental shortcuts that, while allowing for speedy action, can result in less-than-optimal judgments. For example, decision making is influenced by the way choices are described, or framed. In framing a choice, we weigh losses far more heavily than equivalent...