Creating Our Own Simulations

FOR RENÉ DESCARTES, minds were essentially thinking (or feeling) things. For the founding fathers of behaviorism, minds were identical with behaviors-talking, habits, dispositions to act in one way or another. More recently, minds have been imagined as a kind of computer: the software running on the hardware of the brain.

- BRIAN L. KEELEY

For Andy Clark, a cognitive scientist and philosopher at the University of Sussex in the United Kingdom, minds are first and foremost prediction machines. "Instead of constantly expending large amounts of energy on processing incoming sensory signals," he writes in The Experience Machine, "the bulk of what the brain does is learn and maintain a model of body and world." Our mind/brain is "a kind of constantly running simulation of the world around us-or at least, the world as it matters to us."

In other words, while people typically imagine the mind taking in information through our senses and then processing that information to create a model of the world that we experience and act upon, Clark reverses the order: Minds create a model of the world, and the senses tell us how to update the model if the world is different from what was predicted. Those predictions make up most of what we experience-but when things don't go as expected, the mind makes corrections to improve the model.

This may seem counterintuitive (and it is), but Clark makes a strong case in a very accessible and engaging book, bringing together a number of recent trends in the sciences of the mind, including the importance of the body to our mental processes (what's called "embodiment") and how our day-to-day cognition extends out into the world through our use of tools. Along the way, he shows how his approach can explain a diverse set of phenomena, including illusions, mood disorders, chronic pain in the absence of tissue damage, and why police mistakenly see weapons where there are none.