Knight Dunlap (November 21, 1875 – August 14, 1949) was an American psychologist and a past president of the American Psychological Association.
He grew up in rural California and was educated at the University of California, Berkeley. He served as APA president in 1922. He developed a form of paradoxical therapy called 'negative practice' "making an effort to do the things that one has been making an effort not to do." through this procedure he hoped to extinguish the troublesome behavior by perhaps "bringing under voluntary control responses which had been involuntary." (Paradoxical Psychotherapy, Weeks and L'Abate p.9)
In the 1920s, Dunlap argued for the standardization of design in traffic signals and signs, noting that the color red did not always signify "stop" to a motorist. At an APA meeting in 1938, he criticized psychoanalysis and said that sometimes its subjects had physical illnesses and simply required medical treatments such as insulin. In the 1940s, he conducted an experiment with color blindness that was treated with cobra venom and vitamins.
Dunlap died in South Carolina in 1949.