ELIZA
An early conversational program that imitated a psychotherapist by rephrasing what users typed, and surprised its author with how seriously people took it.
Joseph Weizenbaum wrote ELIZA at MIT between 1964 and 1966 and described it in the journal Communications of the ACM in January 1966. The program matched keywords in a typed sentence and answered with a template, often turning the user's words back as a question.
Its best known script, called DOCTOR, imitated a Rogerian therapist, a style that lets the therapist ask questions without offering information. Weizenbaum was struck that users, including his own secretary, treated the program as if it understood them. He became an early critic of attributing human understanding to computers.
Why it matters
ELIZA is the ancestor of the chatbot and the source of the term 'ELIZA effect', the habit of reading understanding into simple text responses. It remains a standard example in discussions of how people respond to conversational software.
Key facts
- Described in Communications of the ACM, January 1966.
- Ran on an IBM 7094 at MIT.
- Used pattern matching, not understanding.
- Gave its name to the 'ELIZA effect'.
Sources
- Campbell-Kelly, Martin, and William Aspray, et al. Computer: A History of the Information Machine. 3rd ed. Westview Press, 2013.
- Weizenbaum, Joseph. "ELIZA: A Computer Program for the Study of Natural Language Communication Between Man and Machine." Communications of the ACM 9, no. 1 (1966).
- Weizenbaum, Joseph. Computer Power and Human Reason. W. H. Freeman, 1976.