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02/11/2004 08:00:00

Zombie Behaviors Are Part of Everyday Life, According to Neurobiologists

PASADENA, Ca.--When you're close to that woman you love this Valentine's Day, her fragrance may cause you to say to yourself, "Hmmm, Chanel No. 5," especially if you're the suave, sophisticated kind. Or if you're more of a missing link, you may even say to yourself, "Me want woman." In either case, you're exhibiting a zombie behavior, according to the two scientists who pioneered the scientific study of consciousness.

Longtime collaborators Christof Koch and Francis Crick (of DNA helix fame) think that "zombie agents"--that is, routine behaviors that we perform constantly without even thinking--are so much a central facet of human consciousness that they deserve serious scientific attention. In a new book titled The Quest for Consciousness: A Neurobiological Approach, Koch writes that interest in the subject of zombies has nothing to do with fiction, much less the supernatural. Crick, who for the last 13 years has collaborated with Koch on the study of consciousness, wrote the foreword of the book.

The existence of zombie agents highlights the fact that much of what goes on in our heads escapes awareness. Only a subset of brain activity gives rise to conscious sensations, to conscious feelings. "What is the difference between neuronal activity associated with consciousness and activity that bypasses the conscious mind?" asks Koch, a professor at the California Institute of Technology and head of the Computation and Neural Systems program.

Zombie agents include everything from keeping the body balanced, to unconsciously estimating the steepness of a hill we are about to climb, to driving a car, riding a bike, and performing other routine yet complex actions. We humans couldn't function without zombie agents, whose key advantage is that reaction times are kept to a minimum. For example, if a pencil is rolling off the table, we are quite able to grab it in midair, and we do so by executing an extremely complicated set of mental operations. And zombie agents might also be involved, by way of smell, in how we choose our sexual partners.

"Zombie agents control your eyes, hands, feet, and posture, and rapidly transduce sensory input into stereotypical motor output," writes Koch. "They might even trigger aggressive or sexual behavior when getting a whiff of the right stuff.

"All, however, bypass consciousness," Koch adds. "This is the zombie in you."

Zombie actions are but one of a number of topics that Koch and Crick have investigated since they started working together on the question of the brain basis of consciousness. Much of the book concerns perceptual experiments in normal people, patients, monkeys, and mice, that address the neuronal underpinnings of thoughts and actions.

As Crick points out in his foreword, consciousness is the major unsolved problem in biology. The Quest for Consciousness describes Koch and Crick's framework for coming to grips with the ancient mind-body problem. At the heart of their framework is discovering and characterizing the neuronal correlates of consciousness, the subtle, flickering patterns of brain activity that underlie each and every conscious experience.

The Quest for Consciousness: A Neurobiological Approach will be available in bookstores on February 27. For more information, see www.questforconsciousness.com. For review copies, contact Ben Roberts at Roberts & Company Publishers at (303) 221-3325, or send an e-mail to bwr@roberts-publishers.com.

Written by Robert Tindol