Harry Frederick Harlow (October 31, 1905 – December 6, 1981) was an American psychologist best known for his maternal-separation, dependency needs, and social isolation experiments on rhesus monkeys, which manifested the importance of caregiving and companionship to social and cognitive development. He conducted most of his research at the University of Wisconsin–Madison, where humanistic psychologist Abraham Maslow worked with him for a short period of time. Harlow's experiments were ethically controversial; they included creating inanimate wire and wood surrogate "mothers" for the rhesus infants. Each infant became attached to its particular mother, recognizing its unique face. Harlow then investigated whether the infants had a preference for bare-wire mothers or cloth-covered mothers in different situations: with the wire mother holding a bottle with food, and the cloth mother holding nothing, or with the wire mother holding nothing, while the cloth mother held a bottle with food. The monkeys overwhelmingly chose the cloth mother, with or without food, only visiting the wire mother that had food when needing sustenance. Later in his career, he cultivated infant monkeys in isolation chambers for up to 24 months, from which they emerged intensely disturbed. Some researchers cite the experiments as a factor in the rise of the animal liberation movement in the United States. A Review of General Psychology survey, published in 2002, ranked Harlow as the 26th most cited psychologist of the 20th century. Biography Harry Harlow was born on October 31, 1905, to Mabel Rock and Alonzo Harlow Israel. Harlow was born and raised in Fairfield, Iowa, the third of four brothers. Little is known of Harlow's early life, but in an unfinished autobiography he recollected that his mother was cold to him and he experienced bouts of depression throughout his life. After a year at Reed College in Portland, Oregon, Harlow obtained admission to Stanford University through a special aptitude test. After a semester as an English major with nearly disastrous grades, he declared himself as a psychology major. Harlow attended Stanford in 1924, and subsequently became a graduate student in psychology, working directly under Calvin Perry Stone, a well-known animal behaviorist, and Walter Richard Miles, a vision expert, who were all supervised by Lewis Terman. Harlow studied largely under Terman, the developer of the Stanford-Binet IQ Test, and Terman helped shape Harlow's future. After receiving a PhD in 1930, Harlow changed his name from Israel to Harlow. The change was made