Artificial IntelligenceIntelligence

Ian Gentipg@cs.st-and.ac.uk

The Turing Test

Artificial IntelligenceIntelligence

Part I : Turing’s Imitation GamePart II: Some sample games

from the 60’s to the 90’s

The Turing Test

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Alan M Turing, Hero

Helped to found theoretical CS 1936, before digital computers existed

Helped to found practical CS wartime work decoding Enigma machines ACE Report, 1946

Helped to found practical AI first (simulated) chess program

Helped to found theoretical AI …

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Can Machines Think?Computing Machinery and Intelligence

Alan M Turing Mind, Vol LIX, Number 236 (1950) Can be found reprinted in many places e.g. Computers and Thought

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Can Machines Think?

Turing starts by defining machine & think Will not use everyday meaning of the words

otherwise we could answer by Gallup poll Instead, use a different question

closely related, but unambiguous “I believe the original question to be too meaningless

to deserve discussion”

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The Imitation Game

Interrogator in one room digital computer in another room person in a third room

From typed responses only, can interrogator distinguish between person and computer?

If the interrogator often guesses wrong, say the machine is intelligent.

Usually done with one machine/person at a time

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A sample imitation game

Turing suggests some specimen Q & A’s: Q: Please write me a sonnet on the subject of the Forth Bridge A: Count me out on this one, I never could write poetry Q: Add 34957 to 70764.

(pause about 30 seconds) A: 105621 Q: Do you play chess? A: Yes Q: I have K at my K1, and no other pieces. You have only K at K6 and R

at R1. It is your move. What do you play? (pause about 15s)

A: R-R8 mate

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What did Turing think?

Turing (in 1950) believed that by 2000 computers available with 128Mbytes storage programmed so well that interrogators have only a 70%

chance after 5 minutes of being right “By 2000 the use of words and general educated

opinion will have altered so much that one will be able to speak of machines thinking without expecting to be contradicted”

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Objections and Responses

Turing discusses responds to some objections Some of them can be dealt with quite quickly

The Theological Objection Man has a soul, machines do not AT: Can we deny His power to give a soul to a machine

Heads in the sand I don’t like the idea so I will ignore it

Argument from various disabilities No machine can X (e.g. tell right from wrong) AT: Becomes a less powerful argument each day

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Some more objections

Lady Lovelace’s [Ada’s] objection computers do whatever we know how to order them to perform

, so computers cannot do anything really new AT: Machines constantly surprise us.

Argument from informality of behaviour impossible to write down formal rules for every situation AT: Scientifically impossible to prove people not driven by rules

Argument from ESP Telepathy would let humans win imitation game AT: Put competitors in ‘telepathy-proof’ room (!)

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Three more serious objections

Argument from Consciousness “No mechanism could feel pleasure, grief … AT: Danger of Solipsism AT: Imitation game exists now - in oral exams Probably the most contentious objection

Argument from continuity in the nervous system the brain does not operate digitally AT: computers can simulate continuous behavior, eg.

Statistically

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Three more serious objections

Mathematical Objection Godel’s theorem, Halting problem, etc, show that

machines cannot do ‘meta-reasoning’. AT: We too often give wrong answers ourselves to be

justified in being very pleased at fallibility of machinesThe mathematical, consciousness, and continuity

arguments deserve further discussion, … … but that’s another story

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Some Famous Imitation Games

1960s ELIZA Rogerian psychotherapist

1970s SHRDLU Blocks world reasoner

1980s NICOLAI unrestricted discourse

1990s Loebner prize win $100,000 if you pass the test

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The problem with ELIZA

Eliza used simple pattern matching “Well, mymy boyfriend made meme come here” ““YourYour boyfriend made youyou come here?”

Eliza written by Joseph WeizenbaumWeizenbaum so upset at credibility of users…

his secretary wanted to use it only in private psychotherapists excited at prospect of Eliza-booths

… he wrote a book to debunk the possibilities “Computer Power and Human Reason”

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The problem with SHRDLU

SHRDLU had a very limited domain “Look-ma-no-hands” AI

hard to abstract lessons learnt natural language processing intermingled with planning, etc

SHRDLU written by Terry Winograd with this and later work, he made major contributions to AI

especially in natural language processing

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The problem with NICOLAI

NICOLAI was not a computer program!Doug Hofstadter conducted dialogue, believing NICOLAI

was electronic (Almost) passed the Reverse Turing TestTricks like the occasional dumb answer

but “too much cleverness in these weird responses”

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The problem with the Loebner PrizeJason Hutchens programmed the 1996 winnerThen wrote an article

“How to pass the Turing test by cheating” ! “Turing’s imitation game in general is inadequate as a test of

intelligence, as it relies solely on the ability to fool people, and this can be very easy to achieve, as Weizenbaum found.”

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Summary: The Turing Test

The Turing test turns a philosophical question ...Can Machines think?

… Into an operational oneCan machines play the imitation game?

We are not near writing programs to pass the testThe Turing test does NOT drive much AI research Improving the capabilities of computers DOES