Arthur Jensen

Based on Wikipedia: Arthur Jensen

The Conductor Who Became Psychology's Most Divisive Figure

Before Arthur Jensen became one of the most controversial scientists in American history, he dreamed of standing before an orchestra. At fourteen years old, he conducted a band that won a nationwide competition in San Francisco. He studied under Nikolai Sokoloff, one of the great conductors of the era. After graduating from Berkeley, he moved to New York primarily to be near Arturo Toscanini, the legendary Italian maestro whose perfectionism and fiery temperament had made him a cultural icon.

He never became a conductor. Instead, Jensen became something perhaps more influential and certainly more disputed: the psychologist whose 1969 paper asking "How Much Can We Boost IQ and Scholastic Achievement?" ignited a firestorm that would burn for decades and whose embers still glow today.

The paper became one of the most cited in the history of psychological research. Many of those citations were rebuttals.

A Winding Path to Controversy

Jensen was born in San Diego in 1923 to a family of practical people. His father ran a lumber and building materials company. His paternal grandparents had emigrated from Denmark; his mother was half Polish-Jewish, half German. As a child, he showed the kind of scattered brilliance that often precedes unconventional careers—he was fascinated by herpetology, the study of reptiles and amphibians, and played clarinet in the San Diego Symphony orchestra.

His academic path was equally wandering. He earned his bachelor's degree in psychology from Berkeley in 1945, but then took seven years to complete a master's degree at San Diego State College. His doctorate came from Columbia University in 1956, where he studied clinical psychology under Percival Symonds. His dissertation focused on the thematic apperception test, a psychological assessment where people tell stories about ambiguous images, revealing—theoretically—their underlying motivations and concerns.

Between his musical ambitions and his academic career, Jensen worked as a social worker for the San Diego Department of Public Welfare. He also wrote an unpublished book-length manuscript about Mahatma Gandhi, whose life and philosophy deeply moved him. This detail is worth pausing on: the man who would later be accused of providing intellectual ammunition for racists once devoted substantial energy to studying the life of history's most famous advocate of nonviolent resistance and human dignity.

After completing postdoctoral work in London with Hans Eysenck—himself a controversial figure in psychology—Jensen returned to Berkeley as a professor. He received tenure in 1962. His early research focused on learning difficulties among what were then called "culturally disadvantaged students." He wanted to understand why some children struggled in school.

Two Kinds of Learning

From extensive testing of schoolchildren, Jensen developed a framework that would shape his career. He proposed that learning ability comes in two distinct flavors.

Level I is associative learning. Think of it as the brain's recording function—memorizing facts, retaining information, learning by repetition. When you memorize multiplication tables or vocabulary words, you're using Level I abilities.

Level II is conceptual learning. This is the brain's processing function—taking information and transforming it, seeing patterns, solving novel problems, drawing inferences. When you figure out how to solve a math problem you've never seen before, or understand why a historical event happened based on the circumstances, you're using Level II abilities.

Jensen eventually became a major advocate for what psychologists call g, or the general factor of intelligence. This is an abstraction that emerges from a curious statistical observation: performance on any cognitive test tends to correlate positively with performance on every other cognitive test. People who do well on vocabulary tests tend to do well on spatial reasoning tests tend to do well on memory tests. The g factor is the mathematical phantom that haunts all these correlations—the underlying something that seems to influence everything cognitive.

The concept of g had been around since Charles Spearman proposed it in 1904, but it had fallen somewhat out of favor. Jensen helped revive it. His Level II conceptual learning was essentially synonymous with g.

The Harvard Paper

In February 1969, the Harvard Educational Review published Jensen's paper "How Much Can We Boost IQ and Scholastic Achievement?" The answer, Jensen argued, was: not much.

The paper examined Head Start, the federal program launched in 1965 to provide early childhood education to disadvantaged children. Head Start was a signature initiative of President Lyndon Johnson's War on Poverty, based on the hope that enriched early environments could help close educational gaps. Jensen concluded that the program had failed to produce lasting IQ gains.

This alone would have been controversial. But Jensen went further.

He argued that roughly eighty percent of the variation in IQ scores within the population he studied was due to genetic factors, with only the remaining twenty percent attributable to environment. And he contended that while Level I associative learning abilities were distributed equally across racial groups, Level II conceptual abilities—the kind measured by IQ tests, the kind that predict academic success—occurred with "significantly greater frequency" in some races than others.

The reaction was immediate and violent. Weeks of protests erupted on the Berkeley campus. Jensen required bodyguards. The protests continued throughout the 1970s. His name became synonymous with a certain kind of scientific racism.

The Nature of the Debate

To understand why Jensen's work provoked such fury, you need to understand the difference between two claims that are easy to conflate.

The first claim is that intelligence, however measured, is substantially heritable—that is, genetic differences between individuals explain a significant portion of the differences in their cognitive abilities. This claim has substantial scientific support. Twin studies, adoption studies, and more recently genomic studies all point to significant heritability of cognitive traits.

The second claim is that average differences in measured intelligence between racial groups are substantially genetic in origin. This is a much stronger claim, and the evidence for it is far weaker. Here's why: heritability within a group tells you nothing definitive about the causes of differences between groups.

Consider this analogy, originally from the geneticist Richard Lewontin. Imagine you have two bags of genetically identical seeds. You plant one bag in rich, well-fertilized soil and the other in poor, nutrient-depleted soil. Within each field, the variation in plant heights will be entirely genetic—the seeds are identical, so any differences must come from genetic variation. But the difference in average height between the two fields is entirely environmental.

Jensen's critics argued that he had committed precisely this error. The historical experiences of different racial groups in America—slavery, segregation, discrimination, poverty—created vastly different environments that could easily explain group differences in test scores without invoking genetics at all.

Jensen, for his part, maintained that he had been misunderstood and misrepresented. He continued to argue that the evidence pointed toward genetic contributions to group differences, though he acknowledged environmental factors played a role.

Associations and Funding

The controversy deepened because of Jensen's associations and funding sources.

He was among the most frequent contributors to Neue Anthropologie, a German journal founded by Jürgen Rieger, who was a neo-Nazi lawyer and political activist. Jensen served on the journal's editorial board alongside Rieger.

He received $1.1 million over his career from the Pioneer Fund. This organization, founded in 1937, has been described by numerous scholars and journalists as racist and white supremacist in orientation. The fund's original purpose included promoting the study of "race betterment" and supporting the repatriation of African Americans to Africa. It contributed a total of $3.5 million to researchers cited in The Bell Curve, the 1994 book by Richard Herrnstein and Charles Murray that reignited the race and IQ controversy for a new generation. Jensen's work was cited twenty-three times in that book's bibliography.

In 1994, Jensen signed "Mainstream Science on Intelligence," an essay published in The Wall Street Journal and signed by fifty-two researchers. The essay, written by Linda Gottfredson, declared what the signers considered the scientific consensus on intelligence following The Bell Curve's publication. Critics saw it as a defense of that controversial book's most explosive claims.

Defenders and Critics

Jensen's scientific legacy is difficult to assess precisely because opinions about him were so polarized.

Some eminent psychologists defended both his science and his character. After receiving honors from the American Psychological Association in 1998, the respected methodologist Paul Meehl wrote that Jensen's contributions "in both quality and quantity, certainly excelled mine" and that he was "embarrassed" the APA had not similarly honored Jensen—a failure Meehl attributed to political correctness.

Psychologist Sandra Scarr, writing in the journal Intelligence, praised Jensen's "uncompromising personal integrity" and described his critics as "politically driven liars, who distort scientific facts in a misguided and condescending effort to protect an impossible myth about human equality."

James Flynn, ironically the researcher who documented the phenomenon that most undermines hereditarian interpretations of IQ—the Flynn Effect, the worldwide rise in IQ scores over time—told The New York Times after Jensen's death that Jensen was without racial bias. Flynn said Jensen had not initially foreseen that his research would be used to argue for racial supremacy. But Flynn also noted that Jensen shifted toward more genetic explanations later in life, and called Jensen's career "emblematic of the extent to which American scholarship is inhibited by political orthodoxy."

On the other side, critics were equally emphatic.

Stephen Jay Gould, the paleontologist and evolutionary biologist, devoted substantial portions of his influential 1981 book The Mismeasure of Man to attacking Jensen's work. Gould argued that Jensen fundamentally misunderstood heritability, using a measure of variation within populations to make claims about differences between populations. He also challenged Jensen's faith in g itself, arguing that the general factor of intelligence was a statistical artifact rather than a real property of minds.

Lisa Suzuki and Joshua Aronson of New York University wrote that Jensen had largely ignored evidence that failed to support his predetermined conclusions.

Melvin Konner of Emory University noted that statements by Jensen and others "rapidly passed into currency in policy discussions. Many of these statements were proved wrong, but they had already influenced some policymakers, and that influence is very difficult to recant."

This last point captures something important about scientific controversy in politically charged domains. By the time evidence accumulates and debates are settled—if they ever are—the policy implications have already been felt.

The Books

Jensen published several major books that remain reference works in their field, regardless of one's views on his conclusions.

Bias in Mental Testing, published in 1980, ran nearly eight hundred pages examining whether standardized tests discriminate against minority groups. Jensen concluded they did not—that tests predicted outcomes equally well across groups, even if groups differed in average scores. Three researchers reviewing the field nineteen years later called the book "exhaustive." Psychologist Kenneth Kaye, reviewing it, endorsed Jensen's distinction between test bias (a technical question about whether tests measure the same thing across groups) and discrimination (a social and political question about how test scores are used).

Straight Talk about Mental Tests, published in 1981, was written for the general public. Reviewers found it a clear introduction to psychometrics, the science of mental measurement.

The g Factor: The Science of Mental Ability, published in 1998, synthesized decades of research on general intelligence—its intellectual history, biological correlates, heritability, and predictive power.

Clocking the Mind: Mental Chronometry and Individual Differences, published in 2006, explored reaction time as a measure of cognitive processing. Jensen argued that mental chronometry—measuring how quickly the brain processes information—represented a more fundamental approach to understanding intelligence than traditional IQ tests.

A Life's Measure

Arthur Jensen died on October 22, 2012, at his home in Kelseyville, California. He was eighty-nine years old.

In 2002, Steven Haggbloom, writing for the Review of General Psychology, rated Jensen as one of the hundred most eminent psychologists of the twentieth century, based on six different metrics. In 2003, Jensen received the Kistler Prize for contributions to understanding the connection between the human genome and human society. In 2006, the International Society for Intelligence Research gave him its Lifetime Achievement Award.

David Lubinski of Vanderbilt University captured the paradox of Jensen's career: "the extent to which his work was either admired or reviled by many distinguished scientists is unparalleled."

That Jensen was a serious scientist seems clear. He published over four hundred papers in peer-reviewed journals. He served on the editorial boards of major publications. His books were exhaustively researched. His statistical methods were generally sound.

That his work was used to support racist conclusions also seems clear, whether or not that was his intention. The questions he asked, the conclusions he drew, and the associations he kept all pointed in a direction that gave comfort to those who sought scientific justification for racial hierarchy.

The deeper question—whether there was anything to his controversial claims—remains contested. The scientific consensus, to the extent one exists, is that group differences in IQ scores are real but that their causes remain uncertain. The Flynn Effect—the substantial rise in IQ scores worldwide over the twentieth century, far too fast to be genetic—demonstrates that environmental factors can produce large changes in test scores across populations. This makes purely genetic explanations for group differences less plausible, though not impossible.

The Unasked Question

There is perhaps a more fundamental question that Jensen's career raises, one that his defenders and critics alike often failed to address directly: even if group differences in cognitive test scores had some genetic component, what would follow?

The answer, from any reasonable moral or political philosophy, is: very little.

Individual variation within any group vastly exceeds average differences between groups. Knowing someone's race tells you almost nothing useful about their individual cognitive abilities. Policy should be based on individual merit and circumstance, not group averages.

More importantly, human dignity and civil rights do not depend on equal distribution of any particular trait. We do not believe that shorter people deserve fewer rights than taller people, or that those with worse eyesight deserve less consideration than those with better. The premise that IQ differences—whatever their origin—should affect how we treat people is the truly radical claim, and it is one that Jensen's critics sometimes failed to challenge directly enough.

The boy who dreamed of conducting orchestras ended up conducting a very different kind of performance—one whose score was written in statistics and whose audience included both scientists seeking truth and ideologues seeking ammunition. Whether he knew which audience was listening, and whether he cared, remains one of the mysteries of a controversial life.