So you think you know your own brain? After you read Baylor neuroscientist David Eagleman’s breezy treatment of the subject, you will marvel at how much is illusory that we think is real, and how we sometimes function on autopilot without consciously knowing what is happening. He explains how magicians succeed at sleight of hand; and how pedestrians, in plain view, are struck by drivers whose eyes are open but whose brain, at that moment, does not respond to visual stimuli. You can see and not understand. You can understand and not see.

Our sense of time is not entirely real either. Look at your eyes in a mirror. Move your point of focus so that you are seeing your left eye, then your right. Obviously, to perform this task your eyes have to move - but you never see them move. The brain fills in the gaps. In the author’s words: “The brain makes time-saving and resource-saving assumptions and tries to see the world only as well as it needs to.” Consciousness actually interferes with the brain’s desire to perform certain tasks efficiently.

Then there is unconscious learning: “You may have a difficult time putting into words the characteristics of your father’s walk, or the shape of his nose, or the way he laughs - but when you see someone who walks, looks, or laughs like him, you know it immediately.”

In one of the weirdest and most fascinating sections of the book, we learn about something psychologists call unconscious self-love. More people than is statistically likely select mates whose names begin with the same letter as theirs. People named Denise and Dennis are disproportionately likely to become dentists. People born on March 3 (3/3) are statistically overrepresented in Three Forks, Mont. Crazy, right?

Evolution is another important factor in all this. The brain’s circuitry is designed to generate the behavior that promotes survival. People are physically attracted to qualities of beauty that reflect signs of fertility brought on by hormonal changes. No surprise there. But how about this: Tests show that, whether judged by men or women, women are considered most attractive at the peak of fertility in their menstrual cycle. This perception is even confirmed when a person judges relative attractiveness in two photographs taken of a woman at different times of the month! Now that’s the brain working without conscious knowledge.

The question, “What is stronger, biology or willpower?” comes up again and again. The brain interprets the body’s actions and builds stories around them: “If you hold a pencil between your teeth while you read something, you’ll think the material is funnier; that’s because the interpretation is influenced by the smile on your face.” Other questions posed and explained in the book concern hidden impulses and range from the cosmic to the mundane: Is monogamy based on moral character or something in the genes? Is drunken Mel Gibson spewing hateful words the “real” Mel, or is the apologetic Mel saying what he really believes? The answers are far from obvious.

Eagleman says we are just beginning to understand the relationship between the brain and behavior. Why are some people better at impulse control than others? Why can one person resist that piece of chocolate cake and another can’t? Looking at crime and punishment from the perspective of science, he is deeply concerned. He notes that carriers of a particular set of genes are far more likely to commit violence than the rest of the population - in fact, 98.4 percent of death row inmates carry these genes. Yet, before you start thinking of identifying potential criminals through DNA, the fact is that fully one-half of the American population carries these genes. Some of what society labels mental disorders have a physical basis and are more properly termed “organic disorders.” Eagleman wants to see the legal system “customizing” rehabilitation strategies according to biological facts, much as epilepsy or depression is treated. As with chocolate cake, the goal is not to control thought, but to control the nerves that care about long-term consequences. To do so, he says, is more constructive than simply to lay blame.

This is a fascinating book. You’ll be convinced that the future of perception is in the hands of today’s researchers. Recently, the gene for a human photopigment was spliced into color-blind mice. The result: mice with color vision. By modifying the circuitry, neuroscience solves a multitude of organic problems. Still, you should probably think twice if your primary care provider is named Dr. Frankenstein.

Andrew Burstein is Charles P. Manship Professor of History at LSU and author of books on American political culture. His website is:


By David Eagleman; Pantheon, $26.95