YOU NEVER KNOW

ON BEING CERTAIN: BELIEVING YOU ARE RIGHT EVEN WHEN YOU'RE NOT
by Robert A. Burton. St. Martin Press, 2008. ($24.95)

The day after the 1986 Challenger shuttle accident, psychologist Ulric Neisser asked 106 students to write down exactly where they were and what they were doing when they first heard about the explosion. When he interviewed the students two and a half years later, 25 percent of them gave strikingly different accounts. But when confronted with their original journal entries, many students defended their beliefs. One of them answered, “That’s my handwriting, but that’s not what happened.”

In On Being Certain, neuroscientist and novelist Robert A. Burton tries to get to the bottom of the curious sensation he calls the “feeling of knowing”—being certain of a fact despite having no (or even contrary) evidence. Throughout his book, Burton makes the compelling argument that certainty “is neither a conscious choice nor even a thought process.” Instead, he says, that unmistakable sense of certainty “arises out of involuntary brain mechanisms that, like love or anger, function independently
of reason.”

Burton thinks that just as we perceive our external world through our physical senses, our internal world presents itself in the form of feelings, such as familiar or strange and correct or incorrect. And he shows that these inner perceptions are necessary for us to function properly in everyday life, because our thoughts are subject to constant self-questioning. For example, even though reason may tell us that running up a tree to escape a lion is an excellent strategy, experience shows that great strategies can fail and that there may be better options. Because alternative choices are present in any situation, logical thought alone would be doomed to a perpetual “yes, but” questioning routine. Burton reasons that it is the feeling of knowing that solves this dilemma of how to reach a conclusion. Without this “circuit breaker,” indecision and inaction would rule the day.

One of the startling implications of Burton’s thesis is that we ultimately cannot trust ourselves when we believe we know something to be true. “We can’t afford to continue with the outdated claims of a perfectly rational unconscious or knowing when we can trust gut feelings,” he writes. On Being Certain challenges our understanding of the very nature of thought and provokes readers to ask what Burton calls “the most basic of questions”: How do we know what we know?

NEURAL GEOGRAPHY

BEYOND THE ZONULES OF ZINN: A FANTASTIC JOURNEY THROUGH YOUR BRAIN
by David Bainbridge. Harvard University Press, 2008. ($25.95)

When David Bainbridge, a University of Cambridge anatomist, witnessed through ultrasound his daughter’s gestation, he was unexpectedly moved. Mesmerized by the detailed images of her budding nervous system, he saw in her eyes a tiny ring of fibers encircling each lens, known as the zonules of Zinn.

This experience spurred him to write Beyond the Zonules of Zinn, a tale of the brain by a physiologist. Because form often gives insight into function, he uses evolutionary biology to walk us through human gestation, explaining how natural selection favors genes that enhance functions critical to survival, which often later give rise to specialized anatomical features. In the brain we find spectacular geographic specificity, where tiny patchworks of neurons give us language, planning and vision.

Even in a nine-week-old human fetus, a primitive nervous system emerges. Bainbridge explains how a neural bud bulges into a forebrain, midbrain and hindbrain, culminating in the cerebral cortex—the creviced, convoluted tissue layer that makes up the brain’s surface. On the evolutionary trail, he describes how primitive drives (such as hunger, sex and sleep) evolved into higher functions, including memory, learning and emotions.
Gender differences, brain size, intelligence and even bizarre teenage behavior all have underpinnings in neural anatomy. Bainbridge marvels at how the fragile sheet of the cerebral cortex organizes our sensations, leading naturally to consciousness. In contrast to philosophical speculations on consciousness, Bainbridge focuses on neural hardware. Distilling seven leading theories of consciousness, he argues that consciousness is material, not mystical—something “our brain does.”

His tour concludes with the ultimate loss of consciousness, death—reflecting physiologically on near-death experiences. He postulates that survivors’ reports of soaring down tunnels of light and reliving memories reflect the brain’s response to being starved of oxygen and flooded with stress-induced neurotransmitters. Otherwise orderly neural operations most likely go haywire, triggering the visual cortex to generate apparent white light and memory storage mechanisms to go awry. This speculation underscores Bainbridge’s theme—that what often appears to be supernatural really is natural after all.

BRAINS DOWN UNDER

All in the Mind
Listen to the show and read Natasha Mitchell’s blog at www.abc.net.au/rn/allinthemind

Who spends her Saturdays debating the nature of happiness, eavesdropping on brain surgery and investigating the evolutionary reasons for grief? Natasha Mitchell, that’s who—host of the award-winning Australian Broadcasting Corporation radio show All in the Mind, now in its sixth year. Every week for half an hour, Mitchell finds a new doorway through which to explore the world of the brain, whether via the diary of a brain tumor patient or art made by the mentally ill. Her forays, though always creative, never come at the expense of the science: Mitchell is not only fascinated by the mind but also adept at understanding and communicating its nuances.

Based in Melbourne, All in the Mind occasionally focuses on local events and issues such as the Australian science fair, but more often than not the show provides listeners with a rich, global perspective about brain, behavior and scientific research in general. One recent segment, for example, delved into the ways in which animal experimentation ethics differ in Australia, America and the U.K. Mitchell invites listeners from around the world to share their stories and experiences on the air. And although she may be broadcasting from the other side of the world, her warm demeanor and soothing voice recall the girl next door.

The show’s Web site provides free access to previous episodes, transcripts and Mitchell’s recently launched blog, so fans can catch up with the host and her thoughts on the latest neuroscience and psychology news all week long. “Think of it as a digital play space for the mind,” Mitchell says.

QUICK FIX

60-Second Psych
Listen at www.SciAm.com/podcast

Need a conversation starter for your next cocktail party? Grab some quirky, insightful material from 60-Second Psych, a weekly mind-themed podcast produced by Scientific
American online, a sister division of Scientific American Mind. Host Christie Nicholson, SciAm.com’s community editor and a former psychiatric research assistant, covers heady topics with lightning speed: Why does fear boost Iraqi teens’ selfesteem? Do bisexual women have a distinct sexual orientation? And what does neuroimaging tell us about ESP?

Nicholson culls the journals and newsstands for a balanced mix of hard neuroscience and popular psychology stories. Although you might expect the weekly minute of reporting to feel rushed, she takes her time to break down the science in each study.

Her references to pop culture and historical research bring a helpful—and fun—perspective to each installment. In a recent podcast, Nicholson linked Harvard psychologist Steven Pinker’s research on romantic infatuation to the film Fatal Attraction and to Beyonc’s hit song “Crazy in Love.” In 60 seconds, a little something for everybody.