The Roots of Radicalism

Born to Rebel: Birth Order, Family Dynamics, and Creative Lives

by Frank J. Sulloway
Pantheon, 653 pp., $30.00
Frank J. Sulloway
Frank J. Sulloway; drawing by David Levine


The case of the alleged Unabomber, Theodore Kaczynski, grips our imagination, not least as a psychological mystery of childhood development. Why might he have become a driven serial murderer? At first his curriculum vitae—child of liberal parents, Harvard College graduate, brilliant mathematician—might have seemed to point to another career. What was there in his genes or childhood environment that could have stamped him so powerfully?

Less attention has been paid to an even sharper paradox. Theodore’s brother shared approximately half of his genes and grew up in seemingly the identical family environment. Yet one Kaczynski boy may have devoted himself to killing, while the other turned in his brother for a capital offense. There could hardly be a greater contrast between possible lawbreaking and law-abiding behavior. It would be difficult enough to explain such opposites within the same city and social group; how do we explain them in the same family? This is among the questions suggested by Frank Sulloway’s study of siblings.

Polarization between siblings is something that any parent of more than one child witnesses dozens of times daily. For example, each day in the winter, when the heat is turned on in my house, my young sons engage in a battle that would be funny if they didn’t take it so seriously, and if I didn’t wonder about the possible effects of similar battles on the Kaczynski brothers. Before breakfast, both boys sit down to warm themselves on a floor heating grate with twenty-six slats. Each then counts whether his brother’s body unfairly covers more than thirteen slats, and loud arguments begin. The polarization extends to all spheres of life: Joshua beats Max at chess, so Max stops playing chess for two years; Max acquires a pet snake, so Joshua demands his own personal pet snake, then announces a passion for butterflies; and, of course, each complains that the other is receiving more of their parents’ attention.

Psychiatrists and psychologists have stressed the overwhelming formative influence of parents on children. In reality, many or most children spend far more time with siblings than with parents, whether at play, in laughing together, or in exchanging love, hate, and jealousy. Frank Sulloway’s big book explores the effects of those sibling relationships, but it really consists of four books combined into one. It begins by asking why a few scientists, such as Darwin, contribute revolutionary creative advances, while other scientists with superior brains and opportunities fail to do so. It then broadens its aim and explores the effects of family environment—especially of birth order, but also of other family variables—on the personality of anyone, not just of scientists. It turns to political and social revolutionaries and asks what molds them, from Robespierre to Fidel Castro. Through all these discussions runs the fourth theme: how to gain understanding in complex fields like psychology, biography, and history, where outcomes depend on many…

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