Arthur Robert Jensen (August 24, 1923 – October 22, 2012) was an American psychologist and writer. He was a professor of educational psychology at the University of California, Berkeley. Jensen was known for his work in psychometrics and differential psychology, the study of how and why individuals differ behaviorally from one another. He was a major proponent of the hereditarian position in the nature and nurture debate, the position that genetics play a significant role in behavioral traits, such as intelligence and personality. He was the author of over 400 scientific papers published in refereed journals and sat on the editorial boards of the scientific journals Intelligence and Personality and Individual Differences. Jensen was controversial, largely for his conclusions regarding the causes of race-based differences in IQ. A 2019 study found him to be the most controversial intelligence researcher among 55 persons covered. Early life Jensen was born August 24, 1923, in San Diego, California, the son of Linda Mary (née Schachtmayer) and Arthur Alfred Jensen, who operated and owned a lumber and building materials company. His paternal grandparents were Danish immigrants and his mother was of half Polish Jewish and half German descent. As a child, Jensen was interested in herpetology and classical music, playing clarinet in the San Diego Symphony orchestra. Jensen received a B.A. in psychology from the University of California, Berkeley in 1945 and went on to obtain his M.A. in psychology in 1952 from San Diego State College. He earned his Ph.D. in clinical psychology from Columbia University in 1956 under the supervision of Percival Symonds on the thematic apperception test. From 1956 through 1958, he did postdoctoral research at the University of London, Institute of Psychiatry with Hans Eysenck. Upon returning to the United States, he became a researcher and professor at the University of California, Berkeley, where he focused on individual differences in learning, especially the influences of culture, development, and genetics on intelligence and learning. He received tenure at Berkeley in 1962. He concentrated on the learning difficulties of culturally disadvantaged students. Jensen had a lifelong interest in classical music and was, early in his life, attracted by the idea of becoming a conductor himself. At 14, he conducted a band that won a nationwide contest held in San Francisco. Later, he conducted orchestras and attended a seminar given by Nikolai Sokoloff. Soon after graduating from Berkeley, he moved to New York,