Turing test

The Turing test is a proposal for a test of a machine's capability to perform human-like conversation. Described by Alan Turing in the 1950 paper "Computing machinery and intelligence", it proceeds as follows: a human judge engages in a natural language conversation with two other parties, one a human and the other a machine; if the judge cannot reliably tell which is which, then the machine is said to pass the test. It is assumed that both the human and the machine try to appear human. In order to keep the test setting simple and universal (to explicitly test the linguistic capability of some machine), the conversation is usually limited to a text-only channel such as a teletype machine as Turing suggested or, more recently, IRC.

Discussion of relevance

There has been some controversy over which of the alternate formulations of the test Turing intended. (Moor, 2003) The term "Turing Test" is usually taken to indicate a test in which a human judge converses with a human and a computer without knowing which is which.

~ ~ ~ ~ ~ ~ ~ ~ ~ ~

It has been argued that the Turing test so defined cannot serve as a valid definition of machine intelligence or "machine thinking" for at least three reasons:

~ ~ ~ ~ ~ ~ ~ ~ ~ ~

• A machine passing the Turing test may be able to simulate human conversational behaviour, but this may be much weaker than true intelligence. The machine might just follow some cleverly devised rules. A common rebuttal in the AI community has been to ask, "How do we know humans don't just follow some cleverly devised rules?" Two famous examples of this line of argument against the Turing test are John Searle's Chinese room argument and Ned Block's Blockhead argument.
• A machine may very well be intelligent without being able to chat like a human.
• Many humans that we'd probably want to consider intelligent might fail this test (e.g., the young or the illiterate). On the other hand, the intelligence of fellow humans is almost always tested exclusively based on their utterances.

Another potential problem, related to the first objection above, is that even if the Turing test is a good operational definition of intelligence, it may not indicate that the machine has consciousness, or that it has intentionality. Perhaps intelligence and consciousness, for example, are such that neither one necessarily implies the other. In that case, the Turing test might fail to capture one of the key differences between intelligent machines and intelligent people. Of course, machines passing the test would most likely vehemently disagree.

Related Topics:
Consciousness - Intentionality

~ ~ ~ ~ ~ ~ ~ ~ ~ ~

In the words of science popularizer Larry Gonick, "I personally disagree with this criterion, on the grounds that a simulation is not the real thing."

~ ~ ~ ~ ~ ~ ~ ~ ~ ~

These criticisms are directed to the Turing Test so defined, but other interpretations of Turing's "new question" have been discussed. Sterret argues that two distinct tests can be extracted from Turing's 1950 paper, and that, pace Turing's remark, they are not equivalent. The test that employs the party game and compares frequencies of success in the game is referred to as the "Original Imitation Game Test" whereas the test consisting of a human judge conversing with a human and a machine is referred to as the "Standard Turing Test". Sterrett agrees that the Standard Turing Test (STT) has the problems its critics cite, but argues that, in contrast, the Original Imitation Game Test (OIG Test) so defined is immune to many of them, due to a crucial difference: the OIG Test, unlike the STT, does not make similarity to a human performance the criterion of the test, even though it employs a human performance in setting a criterion for machine intelligence. A man can fail the OIG Test, but it is argued that this is a virtue of a test of intelligence if failure indicates a lack of resourcefulness. It is argued that the OIG Test requires the resourcefulness associated with intelligence and not merely "simulation of human conversational behaviour". The general structure of the OIG Test could even be used with nonverbal versions of imitation games (Sterrett 2000).

~ ~ ~ ~ ~ ~ ~ ~ ~ ~

Still other writers (Genova (1994), Hayes and Ford (1995), Heil (1998), Dreyfus (1979)) have interpreted Turing to be proposing that the imitation game itself is the test, without specifying how to take into account Turing's statement that the test he proposed using the party version of the imitation game is based upon a criterion of comparative frequency of success in that imitation game, rather than a capacity to succeed at one round of the game.

~ ~ ~ ~ ~ ~ ~ ~ ~ ~