The Synapse and the Soul

Published July 8, 2008

Wall Street Journal

Human by Michael S. Gazzaniga
(Ecco, 447 pages, $27.50)

What is it that makes us human — that sets us apart from other animals? What drives us to act altruistically? Why do we gossip and flirt and empathize? How do we judge beauty, and why are we impelled to create works of art?

In Human: The Science Behind What Makes Us Unique, Michael S. Gazzaniga argues that modern neuroscience is on the brink of offering us real answers to these questions — answers more reliable and truthful than those that centuries of philosophy, religious tradition and literature have offered. Thanks to advances in brain research, Mr. Gazzaniga believes, “things have changed.” We can at last set aside vague speculation and get down to facts. We can finally understand love and courtship and the roots of morality. We can put an end to the “long windbag discussions about art.” If we want answers, science has them.

Once we have been armed with the latest scientific findings about how our brains came to be and how they function, how ought we to act? The findings of neuroscience do not immediately penetrate to the most intimate levels of personal experience.

What science tells us is simple and, by now, familiar: Who we are today is the result of eons of evolutionary adaptations serving our basic biological impulses to survive and reproduce. Evolutionary pressures shaped our bodies and minds as well as our social behaviors. There is almost nothing in human social life, Mr. Gazzaniga says, that cannot ultimately be explained by recourse to evolution.

“All those social relationships we now worry about so intensely,” he writes, “are merely byproducts of behavior originally selected to avoid our being eaten by predators.” Our social instincts were formed by “hunting, herding, hiding, and hustling.” Mr. Gazzaniga even takes a stab at explaining the supposed biological origins of religious belief, although that section of his argument is (blessedly) brief. In essence, he claims that religious practices and beliefs satisfy certain “moral modules” — innate affinities for things like hierarchy, purity and coalitions.

Mr. Gazzaniga is at his best when he is describing his own research with brain-damaged and split-brain patients — that is, patients in whom the tissue between the left and right brain hemispheres has been severed. He tells of one woman who, “although she was being examined in my office at New York Hospital, claimed we were in her home in Freeport, Maine.” A lesion on her brain had left her so convinced that she was really at home that she subordinated any conflicting information. When Mr. Gazzaniga asked her why, if she really were in her house, there were elevators outside the door, she responded: “Doctor, do you know how much it cost me to have those put in?”

By demonstrating the organic origins of our most basic sense of our selves, such stories can challenge our understanding of personhood, agency and identity. Unfortunately, Mr. Gazzaniga buries such provocative anecdotes amid the clutter of too-familiar findings from the evolutionary-psychology crowd. How many times must we be told that symmetrical faces, suggesting health, tend to be more attractive?

The whole effort is hindered by Mr. Gazzaniga's quippy writing style (“Are you saying the big brain is for flirting? Does that mean that Frenchmen have the biggest brains?”) and his tendency to plod from one study to the next. Science is, to be sure, a vast collaborative enterprise, but Mr. Gazzaniga's book at times reads like an interminable bibliography or faculty directory. He quotes so often, and at such length, from a few researchers — e.g., social psychologist Jonathan Haidt, primate researcher Richard Wrangham and Palm Pilot inventor Jeff Hawkins — that even a patient reader might be tempted to put down Mr. Gazzaniga's book and pick up theirs.

More important, Mr. Gazzaniga does little to explore the implications of the research he describes. Once we have been armed with the latest scientific findings about how our brains came to be and how they function, how ought we to act? The findings of neuroscience do not immediately penetrate to the most intimate levels of personal experience. If you are scared of heights, it will make you no less afraid to hear that the “actual cause” of your feeling is a catecholamine rush. But neuroscience is increasingly playing a role in marketing, education and the law, and Mr. Gazzaniga offers no insights into whether this growing influence is justified or appropriate.

To the extent that Mr. Gazzaniga provides any guidance about the future, it is that he believes the evolution of our brains isn't over yet. Throughout Human, he describes the brain with the computer lingo that saturates so much neuroscience writing: circuits, programs, wiring and so on. In the last and longest chapter, he takes the analogy further by exploring the “interface” between minds and machines — both the researchers who are trying to simulate the human mind through artificial intelligence and those who have sought to use implants to get information into or out of the brain. “Who needs flesh?” he asks.

Mr. Gazzaniga is far too credulous in this closing chapter, especially regarding the extravagant claims of some robotics researchers. But worse, he doesn't consider what the coming age of mind enhancement and neural implants might mean. He concedes that tweaking human biology could have unintended consequences, just as tinkering with the natural world has sometimes gone awry. But he does not acknowledge that science alone cannot judge where our powers over our world and our selves should be limited.

The basic assumption of Human is that biological science is superior to every other way of thinking about human life. But that assumption leaves us unable to judge when science itself has gone too far. We may, in the end, feel compelled to turn to the very sources of wisdom — philosophy, tradition, faith and even “long windbag discussions” — that Mr. Gazzaniga scorns.

Mr. Keiper is the editor of The New Atlantis and a fellow at the Ethics and Public Policy Center.

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