Kenneth Mark Colby (1920 – April 20, 2001) was an American psychiatrist dedicated to the theory and application of computer science and artificial intelligence to psychiatry. Colby was a pioneer in the development of computer technology as a tool to try to understand cognitive functions and to assist both patients and doctors in the treatment process. He is perhaps best known for the development of a computer program called PARRY, which mimicked a person with paranoid schizophrenia and could "converse" with others. PARRY sparked serious debate about the possibility and nature of machine intelligence.