The Bell Curve: Intelligence and Class Structure in American Life (3 page)

The next level is the main text. It is accessible to anyone who enjoys reading, for example, the science section of the news magazines. No special knowledge is assumed; everything you need to know to follow all of the discussion is contained within the book. The main text does include considerable technical material, however. The documentation becomes especially extensive when we come to a topic so controversial that many readers will have a “This can’t possibly be true” reaction.

Sprinkled throughout the book are boxes that add more detail, discuss alternative ways of thinking about the data, or relate tidbits that don’t quite fit in the text. You may skip any of these without interrupting the flow of the narrative, but we think they add something (or they wouldn’t be there), and we encourage you to dip into them.

The endnotes provide the usual scholarly references. Some of them, indicated in text by endnote numbers enclosed in brackets, add short discussions that will be of interest mostly to specialists.

Finally, the appendixes elaborate on key issues. For example, readers who come to the book unfamiliar with statistics will find that Appendix 1 supplies the basics; if you want to know more about the debate over cultural bias in intelligence tests, Appendix 5 guides you through the literature on that issue; and so on. Other appendixes lay out the statistical detail that could not be fit into the main text and was too bulky for a note.

Regarding those pesky impersonal third-person singular pronouns and other occasions when the authors must assign a gender to a fictitious person used to illustrate a point, it seems to us there is a simple, fair solution, which we hereby endorse: Unless there are obvious reasons not to, use the gender of the first author. We use
he
throughout.

This book is about differences in intellectual capacity among people and groups and what those differences mean for America’s future. The relationships we will be discussing are among the most sensitive in contemporary America—so sensitive that hardly anyone writes or talks about them in public. It is not for lack of information, as you will see. On the contrary, knowledge about the connections between intelligence and American life has been accumulating for years, available in the journals held by any good university library and on the computer tapes and disks of public use databases.

People have shied from the topic for many reasons. Some think that the concept of intelligence has been proved a fraud. Others recall totalitarian eugenic schemes based on IQ scores or worry about such schemes arising once the subject breaks into the open. Many fear that discussing intelligence will promote racism.

The friends and colleagues whose concerns we take most seriously say something like this: “Yes, we acknowledge that intelligence is important and that people differ. But the United States is founded on the principle that people should be equal under the law. So what possible relevance can individual differences in intelligence have to public policy? What good can come of writing this book?” In answer, we ask these friends and you, the reader, to share for a moment our view of the situation, perhaps suppressing some doubts and assuming as true things that we will subsequently try to prove are true. Here is our story:

A great nation, founded on principles of individual liberty and self-government that constitute the crowning achievement of statecraft, approaches the end of the twentieth century. Equality of rights—another central principle—has been implanted more deeply and more successfully than in any other society in history. Yet even as the principle of equal rights triumphs, strange things begin to happen to two small segments of the population.

In one segment, life gets better in many ways. The people in this group are welcomed at the best colleges, then at the best graduate and professional
schools, regardless of their parents’ wealth. After they complete their education, they enter fulfilling and prestigious careers. Their incomes continue to rise even when income growth stagnates for everyone else. By their maturity, these fortunate ones commonly have six-figure incomes. Technology works in their behalf, expanding their options and their freedom, putting unprecedented resources at their command, enhancing their ability to do what they enjoy doing. And as these good things happen to them, they gravitate to one another, increasingly enabled by their affluence and by technology to work together and live in one another’s company—and in isolation from everybody else.

In the other group, life gets worse, and its members collect at the bottom of society. Poverty is severe, drugs and crime are rampant, and the traditional family all but disappears. Economic growth passes them by. Technology is not a partner in their lives but an electronic opiate. They live together in urban centers or scattered in rural backwaters, but their presence hovers over the other parts of town and countryside as well, creating fear and resentment in the rest of society that is seldom openly expressed but festers nonetheless.

Pressures from these contrasting movements at the opposite ends of society put terrific stress on the entire structure. The mass of the nation belongs to neither group, but their lives are increasingly shaped by the power of the fortunate few and the plight of the despairing few. The culture’s sense of what is right and wrong, virtuous and mean, attainable and unattainable—most important, its sense of how people are to live together—is altered in myriad ways. The fragile web of civility, mutual regard, and mutual obligations at the heart of any happy society begins to tear.

In trying to think through what is happening and why and in trying to understand thereby what ought to be done, the nation’s social scientists and journalists and politicians seek explanations. They examine changes in the economy, changes in demographics, changes in the culture. They propose solutions founded on better education, on more and better jobs, on specific social interventions. But they ignore an underlying element that has shaped the changes: human intelligence—the way it varies within the American population and its crucially changing role in our destinies during the last half of the twentieth century. To try to come to grips with the nation’s problems without understanding the role of intelligence is to see through a glass darkly indeed, to grope
with symptoms instead of causes, to stumble into supposed remedies that have no chance of working.

We are not indifferent to the ways in which this book, wrongly construed, might do harm. We have worried about them from the day we set to work. But there can be no real progress in solving America’s social problems when they are as misperceived as they are today. What good can come of understanding the relationship of intelligence to social structure and public policy? Little good can come without it.

The first thing that made this book possible was our good fortune in being where we are—Harvard University and the American Enterprise Institute. Different as they are in many ways, these two splendid institutions gave us a gift that is too often taken for granted: freedom and support to pursue our inquiries wherever they took us.

For learned and often creative advice for dealing with methodological issues, our thanks go to James Heckman, Derek Neal, Robert Rosenthal, Donald Rubin, Christopher Winship, and the Harvard Psychology Department’s Seminar on the Analysis of Psychological Data. The staff of the Center for Human Resource Research—Paula Baker must be singled out—were unfailingly ready to answer our questions about the intricacies of the National Longitudinal Survey of Youth. In the world of psychometrics and testing, we benefited especially from the advice of Robert Forsyth, Arthur Jensen, Richard Lynn, Len Ramist, Malcolm Ree, and Frank Schmidt. Others who have read chapters or listened to us try to explain what we’re up to and then have offered advice, or at least raised their eyebrows usefully, are Douglas Besharov, Eileen Blumenthal, John Bunzel, John DiIulio, Christopher DeMuth, David Ellwood, Richard Epstein, Ronald Haskins, James Herrnstein, Karl Hess, Michael Horowitz, Fred Jewett, Michael Joyce, Cheryl Keller, Robert Klitgaard, Irving Kristol, Richard Larry, Marlyn Lewis, Glenn Loury, Harvey Mansfield, Frank Miele, Michael Novak, Warren Reed, Daniel Seligman, Irwin Stelzer, Joan Kennedy Taylor, Abigail Thernstrom, Daniel Vining, Dean Whitla, James Wilson, and Douwe Yntema. Along with some of those already mentioned, John Bishop, Philip Cook, George Borjas, Robert Frank, Sandra Scarr, and Richard Weinberg provided us with drafts of their ongoing work that filled in missing pieces of the puzzle.

We took unblushing advantage of the energy and good nature of research assistants, with Kris Kirby and Ira Carnahan taking on some huge tasks early in the work, followed by the invaluable help of Kristin
Caplice, Joseph Fazioli, and one other who asked to remain anonymous out of his wish to preserve, as he put it, a viable political future.

All of these people, and others whom we have surely forgotten over the years, deserve our thanks for their help, but not the risk of being held accountable for what we’ve done with it.

We were lucky to have Erwin Glikes as our editor and Amanda Urban as our agent—the best in the business, and utterly undaunted by the hazards of this enterprise.
The Bell Curve
is Erwin’s title, and its manuscript was the last he completed editing before his death.

In a list of acknowledgments, we would be remiss not to mention each other. We decided to write this book in November of 1989, and since the spring of 1990 have been working at it nearly full time, for long stretches much more than full time, in continual collaboration. Our partnership has led to a more compelling intellectual adventure and a deeper friendship than we could have imagined. Authorship is alphabetical; the work was symbiotic.

At last, how shall we express our thanks to Susan Herrnstein and Catherine Cox? They could not be, and were not, overjoyed to see their husbands embark on a project as controversial as this one. But they have endured our preoccupation with the book and its intrusion into our families’ lives with love and humor. Beyond that, each of them read the entire manuscript, persuasively but affectionately pressing on us the benefit of their fine judgment, their good sense, and their honesty. In more ways than one, this book could not have been written without their help.

Richard J. Herrnstein
Charles Murray
3 June 1994

THE BELL CURVE

That the word
intelligence
describes something real and that it varies from person to person is as universal and ancient as any understanding about the state of being human. Literate cultures everywhere and throughout history have had words for saying that some people are smarter than others. Given the survival value of intelligence, the concept must be still older than that. Gossip about who in the tribe is cleverest has probably been a topic of conversation around the fire since fires, and conversation, were invented.

Yet for the last thirty years, the concept of intelligence has been a pariah in the world of ideas. The attempt to measure it with tests has been variously dismissed as an artifact of racism, political reaction, statistical bungling, and scholarly fraud. Many of you have reached this page assuming that these accusations are proved. In such a context comes this book, blithely proceeding on the assumption that intelligence is a reasonably well-understood construct, measured with accuracy and fairness by any number of standardized mental tests. The rest of this book can be better followed if you first understand why we can hold such apparently heterodox views, and for this it is necessary to know something about the story of measured intelligence.

Variation in intelligence became the subject of productive scientific study in the last half of the nineteenth century, stimulated, like so many other intellectual developments of that era, by Charles Darwin’s theory of evolution. Darwin had asserted that the transmission of inherited intelligence was a key step in human evolution, driving our simian ancestors apart from the other apes. Sir Francis Galton, Darwin’s young cousin and already a celebrated geographer in his own right, seized on this idea and set out to demonstrate its continuing relevance by using the great families of Britain as a primary source of data. He presented evidence that intellectual capacity of various sorts ran in families in
Hereditary Genius,
published just a decade after the appearance of
Origin of Species
in 1859. So began a long and deeply controversial association between intelligence and heredity that remains with us today.
¹

Galton realized that he needed a precise, quantitative measure of the mental qualities he was trying to analyze, and thus he was led to put in formal terms what most people had always taken for granted: People vary in their intellectual abilities and the differences matter, to them personally and to society.
²
Not only are some people smarter than others, said Galton, but each person’s pattern of intellectual abilities is unique. People differ in their talents, their intellectual strengths and weaknesses, their preferred forms of imagery, their mental vigor.

Working from these observations, Galton tried to devise an intelligence test as we understand the term today: a set of items probing intellectual capacities that could be graded objectively. Galton had the idea that intelligence would surface in the form of sensitivity of perceptions, so he constructed tests that relied on measures of acuity of sight and hearing, sensitivity to slight pressures on the skin, and speed of reaction to simple stimuli. His tests failed, but others followed where Galton had led. His most influential immediate successor, a French psychologist, Alfred Binet, soon developed questions that attempted to measure intelligence by measuring a person’s ability to reason, draw analogies, and identify patterns.
³
These tests, crude as they were by modern standards, met the key criterion that Galton’s tests could not: Their results generally accorded with common understandings of high and low intelligence.