Eliza was an early natural language processing computer program developed in 1966 by Joseph Weizenbaum. The program was designed to simulate a conversation between a therapist and patient by turning the user's input into questions. It worked by analyzing keywords in the input, transforming the sentence based on rules associated with those keywords, or providing a generic response if no keywords were found. Various versions of Eliza are still available for download or use online to demonstrate its conversational abilities.

1. www.sti-innsbruck.at© Copyright 2008 STI INNSBRUCK www.sti-innsbruck.at
Birgit Juen

2. www.sti-innsbruck.at
Who is Eliza?
• Computer program developed in 1966 by Joseph Weizenbaum
(* 8. Jannuary 1923, † 5. March 2008).
• Very early example of natural language processing.
• One of the first chatterbots in existence.
• Named after Eliza Doolittle, a character in George Bernard Shaw’s Play
Pygmalion.
2

3. www.sti-innsbruck.at
Who is Eliza?
• The program can simulate a human-like interaction.
• Its mission was the attempt to replicate the conversation between a
psychoanalyst and a patient. In a therapeutic situation a human being
can reply to a statement with a question, that indicates very little
specific knowledge of the topic.
3

4. www.sti-innsbruck.at
How does it work?
• Basically ELIZA works by turning everything you say around:
– Input text is read and inspected for keywords,
– sentence is transformed according to a rule associated with the keyword,
– if no keyword is found, a content-free remark is retrieved.
• More complex:
– Keywords may have a rank; identification of the most important keyword.
– Identification of some minimal context within which the chosen keyword appears.
– Choice of an appropriate transformation rule + making of the transformation.
– Respond “intelligently” even if no keyword is detected in the input text.
4

5. www.sti-innsbruck.at
Demo
• Various versions available for download or to use online i.E.
http://www.masswerk.at/elizabot/eliza.html
5

6. www.sti-innsbruck.at
What Siri says about Eliza
6

7. www.sti-innsbruck.at
Reference
• J. “ELIZA – A Computer Program For the Study of Communication Between
Man And Machine”. In Communications of the ACM Volume 9, Number 1
(January 1966), pp. 36-45.
http://dl.acm.org/ft_gateway.cfm?id=365168&ftid=64039&dwn=1&CFID=383
890646&CFTOKEN=12646427
• http://en.wikipedia.org/wiki/ELIZA
7