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Person or computer: could you pass the Turing Test?

As mentioned already on this site and others, this year marks the 100th anniversary of the birth of famed British mathematician Alan Turing. The outline of his remarkable life and sad ending has by now…

According to some, computer intelligence is on course to match human intelligence by 2045. Sybren A. Stüvel

As mentioned already on this site and others, this year marks the 100th anniversary of the birth of famed British mathematician Alan Turing.

The outline of his remarkable life and sad ending has by now become fairly well known.

Turing laid numerous foundation stones of modern computing, ranging from the deepest mathematical nature of computing (using what are now called Turing machines he provided the modern approach to incompleteness and undecidability) to specific issues of practical design; he also contributed to mathematical biology (morphology) and much else.

At the same time, he played a key role in the British government’s breaking of the German Enigma code at the now-fabled but then ultra-secret Bletchley Park, thus arguably accelerating the end of the second world war.

Alan Turing. Revolweb

Turing was many other things: a world class marathon runner, a troubled homosexual, and an atheist who famously said:

“The universe is a differential equation. Religion is an initial condition.”

His achievements are perhaps most succinctly summarised by Harvard scholar Steven Pinker, who declared:

“It would be an exaggeration to say that the British mathematician Alan Turing explained the nature of logical and mathematical reasoning, invented the digital computer, solved the mind-body problem, and saved Western civilisation. But it would not be much of an exaggeration.”

One of Turing’s many signal contributions was a 1950 article that defined what is now known as the Turing Test.

In it, he proposed a test in which a human “converses” with two entities — one human and one computer program — over a text-only channel (i.e., a computer keyboard/screen), and then attempts to determine which is the human and which is the computer.


If after, say, five minutes of testing, the majority of human interrogators are unable to determine which is which, Turing said that we could claim the computer system has achieved a certain level of intelligence.

Turing’s article even anticipated several possible objections to his test, including mathematical and philosophical objections, which continue to be debated to the present day.

Some potential questions might not be “fair” to a computer. And we all have human acquaintances who might be judged “computer” in such a test.

In the decades since 1950, when Turing proposed the test, it has been widely influential in directing progress in the computing field in general and in artificial intelligence in particular.

Some early attempts at Turing Test programs pointed out both the promise and the perils of this enterprise. In 1966, computer scientist Joseph Weizenbaum created a program, known as ELIZA, which identified keywords in text typed by a human, and then responded with some sort of clever but enquiring response, in the style of a psychologist interviewing a patient.

ELIZA in action. Wikimedia Commons

Although some subjects were genuinely surprised to discover the “psychologist” was a computer, to more sceptical testers its weaknesses quickly became evident.

The present authors do remember enjoying playing with it when personal computers first allowed for relaxed therapy sessions.

Progress in the field languished somewhat during the 70s and 80s, but since 1991 there has been an annual Loebner Prize in artificial intelligence in which ELIZA’s children — now called “chat-bots” — compete to pass the Turing test.

Two recent advances have dramatically enhanced interest:

1) the ready availability of many terabytes of data, from technical documents on every conceivable topic to the growing personal databases of “lifeloggers”

2) sophisticated statistical (computational and mathematical) techniques for organising and classifying this data

This technology was perhaps brought to the public eye most effectively with the recent defeat of two champion human contestants on the American quiz show Jeopardy! by an IBM-developed computer system known as Watson. The video below is illustrative.

Watson is now rapidly moving into specialisations for medicine and voice recognition, among other things. IBM clearly views Apple’s “intelligent personal assistant” Siri, available with the iPhone 4S, as a main target of competition.

Meanwhile Google and AT&T are working on similar systems, according to a recent UK report.

Among other things, Watson-type technology offers amazing opportunities as an intelligent assistant for mathematical research and other specialist fields — both for use by specialists and outsiders.

So far no computer system has passed the Turing test, according to the strict rules of the Loebner Prize competition, but they are getting close.

The 2010 and 2011 competitions were won by a chat-bot computer system known as “CHAT-L,” by artificial-intelligence programmer Bruce Wilcox.

In 2010 this program actually fooled one of the four human judges into thinking it was human.

Photo Extremist

All this raises the question of whether a computer system that finally passes the Turing test is really “conscious” or “human” in any sense.

These issues were summarised by the University of Bourgogne’s Robert M. French in a recent Science article:

“All of this brings us squarely back to the question first posed by Turing at the dawn of the computer age, one that has generated a flood of philosophical and scientific commentary ever since.

“No-one would argue that computer-simulated chess playing, regardless of how it is achieved, is not chess playing. Is there something fundamentally different about computer-simulated intelligence?”

French is among the more pessimistic observers. Others, such as the American futurist Ray Kurzweil are much more expansive.

He predicts that in roughly the year 2045, machine intelligence will match then transcend human intelligence, resulting in a dizzying advance of technology that we can only dimly foresee at the present time – a vision outlined in his book The Singularity Is Near.

Only time will tell when Turing’s vision will be achieved. But civilisation will never be the same once it is.

Further reading:

A version of this article first appeared on Math Drudge.

Join the conversation

9 Comments sorted by

  1. Bruce Tabor

    Research Scientist at CSIRO

    "Person or computer: could you pass the Turing Test? "

    Not sure about me but Stephen Hawking seems to fail it ;-)

  2. Colin Hales

    Researcher at University of Melbourne

    Wouldn't it be ironic if the timing was right, but the method was completely wrong.... the first real artificial _general_ intelligence was not implemented with a computer.

    Seems weird to me. When we made artificial fire we burnt stuff. When we made artificial flight we flew, we didn't get in a flight simulator. Yet for some reason we think artificial general intelligence will result from a computed model of it? Nahhh. Not going to happen.

    Call me weird, iconoclstic ... time will tell I suppose.

  3. Bruce Tabor

    Research Scientist at CSIRO

    A great article. Turing was one of the greatest minds of all time. His untimely passing is an incredible tragedy.

    Like many futurists, Ray Kurzweil's predictions have proven premature in the past and I suspect he is too much of a technological optimist. Still, that doesn't make him completely wrong.

    I don't doubt we'll see machines with human-like intelligence some time this century, but "is there something fundamentally different about computer-simulated intelligence?" I know something of how Watson is thinking. His database (memory) is vast - far larger, faster and less fallible than human memory. His ability to test associations is orders of magnitude faster than a human brain. So how did Brad equal him?

    The issue is we simply don't understand human intelligence.

    1. Colin Hales

      Researcher at University of Melbourne

      In reply to Bruce Tabor

      "The issue is we simply don't understand human intelligence"

      Absolutely. Yet it seems to me that real artificial general intelligence (AGI) might actually be created without actually knowing why.

      Gronk the cave man did not wait for Laviosier to hand over a theory of combustion before cooking dinner with fire. He cooked, and eventually we learned about combustion.

      Same for intelligence?

      Turn it around again:
      if (AGI) is to (artificial fire)
      (a computed model of the physics…

      Read more
    2. Michael Meany


      In reply to Bruce Tabor

      In no way do I wish to devalue Turing's work with this mildly facetious posting. However, here goes.

      In modern parlance Turing's argument can be viewed as an example of the logic that goes something like; "If it walks like a duck, quacks like a duck... It's probably a duck".
      It seems that modelling intelligence on human beings is part of the problem.

      To return to the duck analogy, what do we do with the following. It looks a bit like a duck with a bill and webbed feet. It also looks a bit…

      Read more
  4. Stephen Pritchard

    Researcher, cognitive science

    Turing was brilliant, however I don't reckon the Turing Test was his high point, and it gets far too much coverage compared to Turing's other achievements and writing. In Turing's defense, it is easy to see how he could come up with such a deficient test of intelligence when he doesn't have the exposure to machine and computer capability that we do nowadays.

    1. David Vender

      Tutor at University of Tasmania

      In reply to Stephen Pritchard

      "the Turing Test [as] his high point"? It's hard to say until we know what Turing thought of his 'test'. Did he not say that it was a game of pretence?

      Jaron Lanier in his book "You are not a gadget" says a lot of things that are easy to disagree with, but he's right on the button with the Turing test: it tells us a lot more about human psychology than about machines. Perhaps it was Turing's best joke?

      As to " No-one would argue that computer-simulated chess playing, regardless of how it…

      Read more
  5. Jan Vones

    logged in via Facebook

    Turing is a great man of many accomplishments, but lauding him for the Turing Test is not the best way to praise him. The test tells us something about the intelligence of the questioner, but nothing of the intelligence of the computer. Indeed, unless the computer has programmed itself, any intelligence lies in the mind of its programmers and designers, and not in the machine.

  6. Nebyu Girma

    logged in via Facebook

    I have developed a software in c++ called APR(Any pattern recognizer)
    My program uses no data set to find a pattern.
    It can also be used for graphs.
    I say it has unlimited power.
    At the same time it solves the boundary problem.(uses no calculations to find a boundary for any given image )
    My APR works
    -accept any graph or character
    -classify all the existing patterns or patterns with the same moves.
    -puts them in one boundary
    -gives you the result of that boundary with every movement of that given image by its moves of “X”and”Y” and by the number of pixels used for every moves.
    It uses a linear search. Both for the pattern recognizer and boundary searcher.
    The bottom line is then you can analyze the findings of your image and use it for your own good.
    I just give you the power of all the image information you need.
    And I can adjust MY APR by the way you needs it.