Quoting from the linked blog:
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In many ways, however, Turing’s thought experiment was a much more stringent form of the “Duck Test” used by Loebner. Turing’s original test did not stipulate a time limit, less still a number of judges that needed to be fooled. The test could continue in open-ended, freewheeling discussion indefinitely, presumably getting tougher for the machine all the while.
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However, going back to Turing’s “Computing Machinery and Intelligence” ( http://cogprints.org/499/1/turing.html ):
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I believe that in about fifty years’ time it will be possible, to programme computers, with a storage capacity of about 109 [sic, should this be 10^9?], to make them play the imitation game so well that an average interrogator will not have more than 70 per cent chance of making the right identification after five minutes of questioning.
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So Turing’s test was less stringent than Loebner’s, since Turing proposed a five-minute session, and a 70% threshold for correct identification.
Also, Loebner’s insistence on a character-by-character protocol violates the spirit of Turing’s test. Quoting Turing’s paper again:
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In order that tones of voice may not help the interrogator the answers should be written, or better still, typewritten. The ideal arrangement is to have a teleprinter communicating between the two rooms. Alternatively the question and answers can be repeated by an intermediary.
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Note that “teleprinter” does not necessarily mean character-by-character protocol. Quoting wikipedia ( http://en.wikipedia.org/wiki/Teleprinter ):
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In 1925 Creed acquired the patents for Donald Murray’s Murray code, a rationalised Baudot code, and it was used for their new Model 3 Tape Teleprinter of 1927. This machine printed received messages directly on to gummed paper tape at a rate of 65 words per minute
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Thus, the typing speed of the operator and the typing speed that the receiver saw were essentially disconnected, since the printing occurred at a fixed rate.
Also, the same wikipedia article on Teleprinters says:
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Exchange systems such as Telex and TWX. These created a real-time circuit between two machines, so that anything typed on one machine appeared at the other end immediately. US and UK systems had actual telephone dials; German systems did “dialing” via the keyboard. Typed “chat” was possible, but because billing was by connect time, it was common to prepare messages on paper tape and transmit them without pauses for typing.
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So once again, in typed chats of Turing’s time using teleprinters, the typing characteristics of the sender were essentially eliminated by the teleprinter. The modern equivalent is the message-by-message protocol, which has become so popular that no one (except Loebner) uses character-by-character anymore.
[Message-by-message protocol is better because reading is faster than writing, so when you’re on the receiving end of a character-by-character message it feels silly to have to wait for the sender to find the right keys. Message-by-message also allows for editing before you hit “enter”, so you have more control over your communication. It’s interesting how in the online ai-class and Thrun’s robotic car class at udacity.com, most of the mechanical writing was edited out, so that the viewers didn’t have to sit through the slow process of handwriting. The main point was that the content was the important part, not the process by which the letters that conveyed the content were written onto the screen.]
Turing’s point was clearly to eliminate any way of identifying intelligence by physical characteristics; Loebner’s character-by-character protocol is plainly an attempt to re-introduce physical characteristics.
Quoting Turing’s paper again:
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The new problem has the advantage of drawing a fairly sharp line between the physical and the intellectual capacities of a man. No engineer or chemist claims to be able to produce a material which is indistinguishable from the human skin. It is possible that at some time this might be done, but even supposing this invention available we should feel there was little point in trying to make a “thinking machine” more human by dressing it up in such artificial flesh. The form in which we have set the problem reflects this fact in the condition which prevents the interrogator from seeing or touching the other competitors, or hearing -their [sic, shouldn’t the “-” be deleted?] voices.
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Loebner’s character-by-character protocol misses Turing’s main point, which is that factors such as typing speed or accuracy are irrelevant to Artificial Intelligence.