In 1966, Joseph Weizenbaum, a professor of computer science at MIT, create, as an experiment in natural language processing, a computer program called ELIZA that carried on a conversation by replying to typed-in statements with printed words. [...] The resulting persona, Eliza, was that of a Rogerian therapist, the kind of cliniciam who echoes back the concerns of the patient without interpretation. [...] To Weizenbaum's dismay, a wide range of people, including his own secretary, would "demand to be permitted to converse with the system in private, and would, after conversing with it for a time, insist, in spite of [Weizenbaum's] explanations, that the machine really understood them." [...] Weizenbaum had set out to make a clever computer program and had unwittingly created a believable character. He was so disconcerted by his achievement that he wrote a book warning of the dangers of attributing human thought to machines.