Arthur Jensen’s life is characterized by a strong defense of the findings he made during his investigations. This has been of great interest for the psychology of individual differences and, above all, in the study of intelligence.

However, it can be said that just as he was a prolific scientist, he was also a controversial figure, especially when he tried to make the world aware of his findings on racial differences in the cognitive area. Let’s see what controversy his work generated through this biography of Arthur Jensen .

Brief biography of Arthur Jensen

Arthur Robert Jensen was born on August 24, 1923, in San Diego, California, USA. He studied at the University of California, Berkeley, and also at San Diego State College and Columbia University.

He wrote his doctoral thesis with Percival Symonds on the Thematic Apperception Test, a projective test which is based on the idea that the unconscious takes shape and projects itself onto plates, revealing aspects of personality, needs and vital desires that one wishes to fulfil, as well as problem-solving skills. Between 1956 and 1958 he carried out postdoctoral research at the University of London, in its institute of psychiatry together with Hans Eysenck.

Upon his return to the United States, he became a professor and researcher at the University of California, where he focused on individual differences and learning . Within his studies on how children learn, he focused especially on differences in the degree of difficulty in learning between different ethnic groups, especially if the ethnic group under study has cultural characteristics that place them at a disadvantage.

During his years of training and research he was influenced by Charles Spearman and Hans Eysenck. In his work he touched upon several fields of psychology, especially educational psychology, genetics of behavior, intelligence and cognition .


Apart from his professional career, little is known about Arthur Jensen’s intimate life. He was married to his wife Barbara and always felt a great interest in music. He wanted to be a conductor and, at the age of fourteen, he participated in a national contest in the city of San Francisco conducting a band, winning it.

Arthur Jensen died on October 22, 2012 in Kelseyville, California, at the age of 89.

Study of intelligence and IQ controversies

Interest in differences in learning ability led Jensen to administer IQ questionnaires in schools across the United States. His results led him to hypothesize about the existence of two different types of learning abilities .

  • Level I: associative learning, stimulus retention, memory.
  • Level II: conceptual learning, more related to problem solving

Over time, Jensen recognized that his level II proposal resembled Charles Spearman’s g-factor idea .

According to Jensen, general cognitive ability is essentially an inherited trait, determined primarily by genetic factors rather than environmental influences. He also understood early on that the ability to memorize was a trait that was similarly distributed across races, while the ability to synthesize, or conceptual learning, was something that seemed to be more developed in white people than in non-white people. It would be this idea that would lead him into controversy.

But the real controversy would come in February 1969, when he published his work in the Harvard Educational Review, entitled How Much Can We Boost IQ and Scholastic Achievement? . In it he concluded that the programs aimed at increasing the IQ in the African-American population had failed and that such an objective was allegedly impossible, given that, according to Jensen, 80% of the IQ variance in the population studied was due more to genetic factors than to environmental influences.

Basically, from this work it could be inferred that black citizens of the United States would never have the same IQ as their white fellow citizens. In a society where the rights of African Americans were being won through struggle and which, since the time of Martin Luther King, had been something of great social tension, this kind of statement was a sore point.

The work became one of the most cited in the history of research in psychology and the study of intelligence, although it can be said that most of the citations were intended to refute what Jensen was arguing.

As a result of the controversy, Jensen’s own life was affected. Crowds protested asking for Arthur Jensen to be fired . It was even the case that the demonstrators went so far as to puncture Jensen’s car tyres and threaten his family. The police considered that these threats were real and that it was necessary for Jensen and his loved ones to leave their home for a while.

It’s safe to say that it’s not like Jensen was a racist. He simply indicated what he had found in his investigations and that, if given the opportunity, he would have researched to see if he could refute himself.

He was aware of the traditional educational differences between whites and blacks in the United States , an environmental factor that was not negligible. What Jensen wanted to indicate with his study was that, although educational programs could mean the improvement of the standard of living and African-American culture, he observed the possibility of differences associated with race.

In fact, and according to Thomas Sowell, who was critical of many of Jensen’s theses but still wanted to defend him, he indicated that Jensen, in 1969, when he was studying African-American children by administering IQ questionnaires to them, scored what he thought were very low scores. Seeing that, he set out to repeat the test, once he got the children used to his presence and calmer. He was willing to replicate any experiment as many times as necessary.

It must be understood that, from a biological perspective, the g-factor was seen as being supported by multiple biological variables and that, based on the apparent differences found between whites and blacks in various cognitive tests, it was understood that race, as a biological factor, could be related to intellectual performance.

It should be noted that races should not be seen as discrete and defined categories (indeed, the concept of race in humans is something that can be strongly criticized), but rather as sets of human characteristics that have been shown more and more in certain populations by processes of natural selection and that are the result of possessing certain genes that have survived the next generation.

Recognition at the academic level

Despite his controversy over the differences in IQ between white and black people, Arthur Jensen received the Kistler Prize in 2003 for his original contributions to understanding the connections between the human genome and the functioning of society. His vision of how genetics influences the functioning of society, related to the genetics of behaviour , has been considered one of the great findings of the 20th century regarding individual differences and their implication at the social level.

In 2006, the American Society for Intelligence Research rewarded and recognized Jensen for his not uncontroversial career and life path for the psychology of individual difference.


Below we will see four books by Arthur Jensen which, although they have not been translated into Spanish, are a good example of this psychologist’s vision of individual differences with respect to the construct of intelligence, as well as showing in some of them concepts related to psychometry and data collection through questionnaires.

1. Bias in Mental Testing (1980)

Bias in Mental Testing , is a book in which examines bias when applying questionnaires that measure IQ , even though they are supposedly standardized.

This is a fairly comprehensive book, about 800 pages long, in which Jensen details the possible evidence of bias in administering intelligence questionnaires in a large number of American populations.

The message that can be taken from the book is that the tests that were being administered showed no bias if they were administered to people who were native or fluent in English.

However, this indicates that, yes , these questionnaires need to be adapted linguistically to groups whose own language is not English , even if they were raised in the United States. This will avoid any kind of cultural bias.

2. Straight Talk about Mental Tests (1981)

The title of this book could be translated as “Direct Conversation on Mental Testing”. It is a book that talks about psychometry but is adapted to a more general public , without necessarily being statesmen or research psychologists.

3. The g Factor: The Science of Mental Ability (1998)

In this book Arthur Jensen explains the concept of the general intelligence factor . He also exposes the historical trajectory of the concept and the different models that have approached it and tried to conceptualize it.

It also defends the heritability of intelligence, in addition to exposing its biological correlates and its predictability.

4. Clocking the Mind: Mental Chronometry and Individual Differences (2006)

In this book he explains how the brain processes information and different ways in which these processes can be measured .

For Jensen, speed of thought seemed to him to be a more important phenomenon than the concept of IQ itself.

While one comes to indicate how quickly one is able to solve problems of any kind, the other conceptualized it more as a kind of score that allowed you to consider yourself above or below in a ranking.

Bibliographic references:

  • Jensen. A. R. (1973). Educational differences. London. Methuen.
  • Jensen, A. R. (1989). “The relationship between learning and intelligence. Learning and Individual Differences. 1: 37-62
  • Rushton, J. P., y Jensen, A. R.. (2005). Treinta años de investigación sobre las diferencias entre blancos y negros en la capacidad cognitiva. Psychology, Public Policy, & the Law, 11, 235-294.
  • Jensen, Arthur R. (primavera 1969). “¿Cuánto podemos aumentar el coeficiente intelectual y el rendimiento escolar?”. Harvard Educational Review. 39 (1): 1-123. doi:10.17763/haer.39.1.l3u15956627424k7