There's something disturbing about holding a human brain in your hands. Cutting away the tangle of fibers holding the brain in place [in the skull] is slow, tedious work. . . . And when the brain is finally eased out, a sickening sucking sound breaks the silence as air rushes in to fill the void left behind.
Holding this person's brain, turning it in your hands. . . you find yourself asking: what did this brain once think; what secret dreams did it hold; what memories are locked forever deep in its folds?
PASADENA, Calif.- So begins the first chapter of Steven R. Quartz's new book, Liars, Lovers, and Heroes: What the New Brain Science Reveals About How We Become Who We Are. Quartz is a cognitive scientist, an associate professor of philosophy, and director of the Social Cognitive Neuroscience Laboratory at the California Institute of Technology. The book, which is being released this week and is cowritten with Terrence J. Sejnowski, a noted neuroscientist at the Salk Institute for Biological Studies in La Jolla, California, suggests a new way of looking at brain development and evolution. It presents insights into such enduring questions as what shapes personality, why we live in groups, the roots of violence, the nature of intelligence, and the biology of happiness. Departing from recent "evolutionary psychology" approaches, the authors call this new view "cultural biology."
In short, Quartz and Sejnowski mull the brain. Not the literal "three-pound clump of (a cadaver's) silent cells," as the book notes, but the marvel of neurons and the connections they form that make us uniquely us.
The traditional question in neuroscience over the last decade or so, says Quartz, has been one of nature vs. nurture. Which has the more profound impact on a brain's development, the genes we inherit or the cultural and environmental milieu in which we are raised and live?
That's no longer in question, he says. The author's make the point that the development of the brain and behavior depends as much on interactions with human culture as it does on our genes. It's a partnership between our genes and the changing, uncertain world of culture that's at the heart of who we are and what the authors mean by the term cultural biology.
"The truth about what drives human development is messy," says Quartz, "but interesting. What makes us who we are is a complex interplay of early experiences, parenting, birth order, friends, and genes, and how these forces interact. It's a richer, more challenging picture of human behavior."
Neuroscientists have learned more about the brain in the last decade than in all previous history, says Quartz, thanks to advances in brain imaging, ever more powerful computer modeling, and, slowly, understanding the "chemical soup" that is the human genome.
The findings that are emerging are providing the first answers to the most basic and perplexing questions all of us ask as we search for meaning in our lives and the world around us.
Some of the answers presented in their book are surprising, paradoxical, and even shocking. Many of the noblest aspects of human nature—altruism, love, courage, creativity—are rooted in brain systems so old that we share them with insects. These systems form the basis, as well, of some of our darkest, most destructive traits, which the book explores through such examples as group violence and terrorism. The authors propose that we survive by creating an ingenious web of ideas for making sense of our world, a symbolic reality we call culture. We pass this on to later generations—in effect a blueprint for survival.
The three pounds of cells that comprise our brains comprise who we are, says Quartz, and somehow give rise to self-reflection and the sense of an enduring personal identity. "We are still a long way from solving the human mystery," observes Quartz, "but these first insights from recent advances in neuroscience offer us tantalizing new clues to some of the oldest questions humans have asked about themselves."
