William John Crozier

William John Crozier ([ˈkrōZHər]; May 24, 1892 – November 2, 1955) was an American physiologist who contributed to the field of psychology through his works on animal behaviour and sensory processes.

Crozier spent the time between 1918–1925 as a professor at different schools including the University of Illinois Medical School and the University of Chicago. In 1927, he became a professor at Harvard where he worked until he retired. He ran a General Physiology laboratory at the University of Harvard, which attracted many young researchers, the most notable being B.F. Skinner.

Crozier spent his time studying the different types of tropisms, as well as the different factors that affected the behaviour of tropisms. Crozier came up with the "parametric analysis" of behaviour, which he believed to be his greatest contribution. In terms of his work in the field of sensory processing, Crozier contributed to the Handbook of General Experimental Psychology, in 1934, by writing a chapter about chemoreception. Throughout his life, Crozier wrote a total of about 300 scientific papers. He died in Belmont in 1955 at the age of 63 due to a heart attack.