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. 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.