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Joseph Weizenbaum Writes ELIZA: A Pioneering Experiment in Artificial Intelligence Programming

1964 to 1966
Weizenbaum in Berlin, 2005

Weizenbaum in Berlin, 2005

Between 1964 and 1966 German and American computer scientist Joseph Weizenbaum at MIT wrote the computer program ELIZA. This program, named after the ingenue in George Bernard Shaw's play Pygmalion, was an early example of primitive natural language processing. The program operated by processing users' responses to scripts, the most famous of which was DOCTOR, which was capable of engaging humans in a conversation which bore a striking resemblance to one with an empathic psychologist. Weizenbaum modeled its conversational style after Carl Rogers, who introduced the use of open-ended questions to encourage patients to communicate more effectively with therapists. The program applied pattern matching rules to statements to figure out its replies. Using almost no information about human thought or emotion, DOCTOR sometimes provided a startlingly human-like interaction.

"When the "patient" exceeded the very small knowledge base, DOCTOR might provide a generic response, for example, responding to "My head hurts" with "Why do you say your head hurts?" A possible response to "My mother hates me" would be "Who else in your family hates you?" ELIZA was implemented using simple pattern matching techniques, but was taken seriously by several of its users, even after Weizenbaum explained to them how it worked. It was one of the first chatterbots in existence" (Wikipedia article on ELIZA, accessed 06-15-2014).

"Weizenbaum was shocked that his program was taken seriously by many users, who would open their hearts to it. He started to think philosophically about the implications of artificial intelligence and later became one of its leading critics.

"His influential 1976 book Computer Power and Human Reason displays his ambivalence towards computer technology and lays out his case: while Artificial Intelligence may be possible, we should never allow computers to make important decisions because computers will always lack human qualities such as compassion and wisdom. Weizenbaum makes the crucial distinction between deciding and choosing. Deciding is a computational activity, something that can ultimately be programmed. Choice, however, is the product of judgment, not calculation. It is the capacity to choose that ultimately makes us human. Comprehensive human judgment is able to include non-mathematical factors, such as emotions. Judgment can compare apples and oranges, and can do so without quantifying each fruit type and then reductively quantifying each to factors necessary for comparison" (Wikipedia article on Joseph Weizenbaum, accessed 06-15-2014).

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