

Turing's new question is: "Are there imaginable digital computers which would do well in the imitation game?" This question, Turing believed, was one that could actually be answered. It opens with the words: "I propose to consider the question, 'Can machines think? '" Because "thinking" is difficult to define, Turing chooses to "replace the question by another, which is closely related to it and is expressed in relatively unambiguous words." Turing describes the new form of the problem in terms of a three-person game called the "imitation game", in which an interrogator asks questions of a man and a woman in another room in order to determine the correct sex of the two players. The test was introduced by Turing in his 1950 paper " Computing Machinery and Intelligence" while working at the University of Manchester. The test results would not depend on the machine's ability to give correct answers to questions, only on how closely its answers resembled those a human would give. If the evaluator could not reliably tell the machine from the human, the machine would be said to have passed the test. The conversation would be limited to a text-only channel, such as a computer keyboard and screen, so the result would not depend on the machine's ability to render words as speech. The evaluator would be aware that one of the two partners in conversation was a machine, and all participants would be separated from one another. Turing proposed that a human evaluator would judge natural language conversations between a human and a machine designed to generate human-like responses.

The Turing test, originally called the imitation game by Alan Turing in 1950, is a test of a machine's ability to exhibit intelligent behaviour equivalent to, or indistinguishable from, that of a human.
