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Brain Wars

Michael Gazzaniga's left-brain, right-brain insight

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Neuroscience has not been kind to the concept of free will. In recent years, the field has given us a picture of the conscious mind that isn't very flattering; it's often an underachiever compared to the unconscious mind, and it's also disturbingly willing to take credit for work it didn't do.

Neuroscience shows us a brain that is determined by its physical characteristics, a brain that can be understood as a very complicated mechanism. Can a mechanism be said to have free will? And if there is no free will, what happens to the concept of personal responsibility?

"When you go through a whole journey of 50 years in brain science, you start wondering about that," author Michael S. Gazzaniga tells me in a recent phone interview. In his new book, Who's in Charge? Free Will and the Science of the Brain, he explores these questions in depth.

Gazzaniga has been involved in studies that clash dramatically with instinctive notions about how our minds work. He once worked with people who'd had such severe epilepsy that the only solution was a surgery to sever the connections between the left and right hemispheres of the brain. The curious thing about this surgery is that patients did not notice any difference, and never reported anything unusual.

Gazzaniga tested these patients by feeding different information to the two hemispheres, and the results are fascinating.

"It's really a multi-agent system in there," he explained. "There's a bazillion control systems in there running our lives. And which one is sort of in our conscious mind at any moment is the result of a competition that goes on with these agents."

But when the hemispheres are severed, the agents on one side can't share information with the agents on the other side. The left hemisphere handles language, so initially, it's the side that answers questions. And when asked, it's happy to explain and take responsibility for actions initiated by the right hemisphere in response to information not at all available to the left.

How? It just makes something up and believes that it is true.

This is due to a part of the brain called the interpreter, and though it may seem a little dishonest, it's just doing its job. The interpreter is what gives you your personal narrative, and sometimes, as Gazzaniga's experiments show, it is wildly incorrect about what's happening in the brain.

Other experiments have shown that often the interpreter will give the conscious mind credit for decisions and actions that actually originated in the unconscious mind.

This has given some reason to think that consciousness might be nothing more than an after-the-fact explainer, a device to rationalize and take credit. But late in the book, Gazzaniga sticks up for conscious decision-making, will power and restraint. These things do exist, he shows us, and he describes their importance in how the mind operates.

So does this mean he believes in free will? "The idea of free will seems antiquated and out-of-date," he says, "and not very helpful to understanding what we humans are all about."

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