Saturday, December 31, 2011

The Turing test V – Strengths and Weaknesses of the Turing Test.

Strengths
Tractability
The philosophy of mind, psychology, and modern neuroscience have been unable to provide definitions of "intelligence" and "thinking" that are sufficiently precise and general to be applied to machines. Without such definitions, the central questions of the philosophy of artificial intelligence cannot be answered. The Turing test, even if imperfect, at least provides something that can actually be measured. As such, it is a pragmatic solution to a difficult philosophical question.

Breadth of subject matter
The power of the Turing test derives from the fact that it is possible to talk about anything. Turing wrote that "the question and answer method seems to be suitable for introducing almost any one of the fields of human endeavor that we wish to include." John Haugeland adds that "understanding the words is not enough; you have to understand the topic as well."
In order to pass a well-designed Turing test, the machine must use natural language, reason, have knowledge and learn. The test can be extended to include video input, as well as a "hatch" through which objects can be passed: this would force the machine to demonstrate the skill of vision and robotics as well. Together, these represent almost all of the major problems of artificial intelligence.
The Feigenbaum test is designed to take advantage of the broad range of topics available to a Turing test. It compares the machine against the abilities of experts in specific fields such as literature or chemistry.

Weaknesses
The Turing test is based on the assumption that human beings can judge a machine's intelligence by comparing its behaviour with human behaviour. Every element of this assumption has been questioned: the human's judgement, the value of comparing only behaviour and the value of comparing against a human. Because of these and other considerations, some AI researchers have questioned the usefulness of the test. In practice, the test's results can easily be dominated not by the computer's (pseudo-?) intelligence, but by the attitudes, skill or naiveté of the questioner.

Human intelligence vs intelligence in general
The Turing test does not directly test whether the computer behaves intelligently - it tests only whether the computer behaves like a human being. Since human behavior and intelligent behavior are not exactly the same thing, the test can fail to accurately measure intelligence in two ways:

Some human behavior is unintelligent
The Turing test requires that the machine be able to execute all human behaviors, regardless of whether they are intelligent. It even tests for behaviors that we may not consider intelligent at all, such as the susceptibility to insults, the temptation to lie or, simply, a high frequency of typing mistakes. If a machine cannot imitate human behavior in detail, it fails the test.
This objection was raised by The Economist, in an article entitled "Artificial Stupidity" published shortly after the first Loebner prize competition in 1992. The article noted that the first Loebner winner's victory was due, at least in part, to its ability to "imitate human typing errors." Turing himself had suggested that programs add errors into their output, so as to be better "players" of the game.

Some intelligent behavior is inhuman
The Turing test does not test for highly intelligent behaviors, such as the ability to solve difficult problems or come up with original insights. In fact, it specifically requires deception on the part of the machine: if the machine is more intelligent than a human being it must deliberately avoid appearing too intelligent. If it were to solve a computational problem that is impossible for any human to solve, then the interrogator would know the program is not human, and the machine would fail the test.
Because it cannot measure intelligence that is beyond the ability of humans, the test cannot be used in order to build or evaluate systems that are more intelligent than humans. Because of this, several test alternatives that would be able to evaluate superintelligent systems have been proposed.

Real intelligence vs simulated intelligence
The Turing test is concerned strictly with how the subject acts — the external behaviour of the machine. In this regard, it takes a behaviourist or functionalist approach to the study of intelligence. The example of ELIZA suggests that a machine passing the test may be able to simulate human conversational behavior by following a simple (but large) list of mechanical rules, without thinking or having a mind at all.
John Searle has argued that external behavior cannot be used to determine if a machine is "actually" thinking or merely "simulating thinking." His chinese room argument is intended to show that, even if the Turing test is a good operational definition of intelligence, it may not indicate that the machine has a mind, consciousness, or intentionality (Intentionality is a philosophical term for the power of thoughts to be "about" something).

Turing anticipated to this line of criticism in his original paper, writing that:
I do not wish to give the impression that I think there is no mystery about consciousness. There is, for instance, something of a paradox connected with any attempt to localise it. But I do not think these mysteries necessarily need to be solved before we can answer the question with which we are concerned in this paper. — Alan Turing, (Turing 1950)

Naivete of interrogators and the anthropomorphic fallacy
The Turing test assumes that the interrogator is sophisticated enough to determine the difference between the behaviour of a machine and the behaviour of a human being, though critics argue that this is not a skill most people have.
Turing does not specify the precise skills and knowledge required by the interrogator in his description of the test, but he did use the term "average interrogator": "[the] average interrogator would not have more than 70 per cent chance of making the right identification after five minutes of questioning". Shah & Warwick (2009c) show that experts are fooled, and that interrogator strategy, 'power' vs 'solidarity' affects correct identification, the latter being more successful.
Chatterbot programs such as ELIZA have repeatedly fooled unsuspecting people into believing that they are communicating with human beings. In these cases, the "interrogator" is not even aware of the possibility that they are interacting with a computer. To successfully appear human, there is no need for the machine to have any intelligence whatsoever and only a superficial resemblance to human behaviour is required. Most would agree that a "true" Turing test has not been passed in "uninformed" situations like these.
Early Loebner prize competitions used "unsophisticated" interrogators who were easily fooled by the machines. Since 2004, the Loebner Prize organizers have deployed philosophers, computer scientists, and journalists among the interrogators. However, even some of these experts have been deceived by the machines.
Michael Shermer points out that human beings consistently choose to consider non-human objects as human whenever they are allowed the chance, a mistake called the anthropomorphic fallacy: They talk to their cars, ascribe desire and intentions to natural forces (e.g., "nature abhors a vacuum"), and worship the sun as a human-like being with intelligence. If the Turing test is applied to religious objects, Shermer argues, then, that inanimate statues, rocks, and places have consistently passed the test throughout history. This human tendency towards anthropomorphism effectively lowers the bar for the Turing test, unless interrogators are specifically trained to avoid it.

Impracticality and irrelevance: the Turing test and AI research
Mainstream AI researchers argue that trying to pass the Turing Test is merely a distraction from more fruitful research. Indeed, the Turing test is not an active focus of much academic or commercial effort—as Stuart Russell and Peter Norvig write: "AI researchers have devoted little attention to passing the Turing test." There are several reasons.
First, there are easier ways to test their programs. Most current research in AI-related fields is aimed at modest and specific goals, such as automated scheduling, object recognition, or logistics. In order to test the intelligence of the programs that solve these problems, AI researchers simply give them the task directly, rather than going through the roundabout method of posing the question in a chat room populated with computers and people.
Second, creating life-like simulations of human beings is a difficult problem on its own that does not need to be solved to achieve the basic goals of AI research. Believable human characters may be interesting in a work of art, a game, or a sophisticated user interface, but they are not part of the science of creating intelligent machines, that is, machines that solve problems using intelligence. Russell and Norvig suggest an analogy with the history of flight: Planes are tested by how well they fly, not by comparing them to birds. "Aeronautical engineering texts," they write, "do not define the goal of their field as 'making machines that fly so exactly like pigeons that they can fool other pigeons.'"
Turing, for his part, never intended his test to be used as a practical, day-to-day measure of the intelligence of AI programs; he wanted to provide a clear and understandable example to aid in the discussion of the philosophy of artificial intelligence. As such, it is not surprising that the Turing test has had so little influence on AI research — the philosophy of AI, writes John McCarthy, "is unlikely to have any more effect on the practice of AI research than philosophy of science generally has on the practice of science."


Based on http://en.wikipedia.org/wiki/Turing_test licensed under the Creative Commons Attribution-Share-Alike License 3.0

Chatbots II - History of Chatbots and their development over time.

In 1950, Alan Turing published his famous article "Computing Machinery and Intelligence" which proposed what is now called the Turing test as a criterion of intelligence. This criterion depends on the ability of a computer program to impersonate a human in a real-time written conversation with a human judge, sufficiently well that the judge is unable to distinguish reliably - on the basis of the conversational content alone - between the program and a real human. The notoriety of Turing's proposed test stimulated great interest in Joseph Weizenbaum's program ELIZA, published in 1966, which seemed to be able to fool users into believing that they were conversing with a real human. However Weizenbaum himself did not claim that ELIZA was genuinely intelligent, and the Introduction to his paper presented it more as a debunking exercise:

[In] artificial intelligence ... machines are made to behave in wondrous ways, often sufficient to dazzle even the most experienced observer. But once a particular program is unmasked, once its inner workings are explained ... its magic crumbles away; it stands revealed as a mere collection of procedures ... The observer says to himself "I could have written that". With that thought he moves the program in question from the shelf marked "intelligent", to that reserved for curios ... The object of this paper is to cause just such a re-evaluation of the program about to be "explained". Few programs ever needed it more.

ELIZA's key method of operation (copied by chatbot designers ever since) involves the recognition of cue words or phrases in the input, and the output of corresponding pre-prepared or pre-programmed responses which can move the conversation forward in an apparently meaningful way (e.g. by responding to any input that contains the word 'MOTHER' with 'TELL ME MORE ABOUT YOUR FAMILY'). Thus an illusion of understanding is generated, even though the processing involved has been merely superficial. ELIZA showed that such an illusion is surprisingly easy to generate, because human judges are so ready to give the benefit of the doubt when conversational responses are capable of being interpreted as "intelligent". Thus the key technique here - which characterises a program as a chatbot rather than as a serious natural language processing system - is the production of responses which are sufficiently vague and non-specific that they can be understood as "intelligent" in a wide range of conversational contexts. The emphasis is typically on vagueness and unclarity, rather than any conveying of genuine information.

More recently, however, interface designers have come to appreciate that humans' readiness to interpret computer output as genuinely conversational - even when it is actually based on rather simple pattern-matching - can be exploited for useful purposes. Most people prefer to engage with programs that are human-like, and this gives chatbot-style techniques a potentially useful role in interactive systems that need to elicit information from users, as long as that information is relatively straightforward and falls into predictable categories. Thus, for example, online help systems can usefully employ chatbot techniques to identify the area of help that users require, potentially providing a "friendlier" interface than a more formal search or menu system. This sort of usage holds the prospect of moving chatbot technology from Weizenbaum's "shelf ... reserved for curios" to that marked "genuinely useful computational methods".

The classic historic early chatterbots are ELIZA (1966) and PARRY (1972). More recent notable programs include A.L.I.C.E., jabberwacky and D.U.D.E (Agence Nationale pour la Recherche and CNRS 2006). While ELIZA and PARRY were used exclusively to simulate typed conversation, many chatterbots now include functional features such as games and web searching abilities. In 1984 a book called The Policeman's Beard is Half Constructed was published, allegedly written by the chatbot Racter (though the program as released would not have been capable of doing so).

One pertinent field of AI research is natural language processing. Usually, weak AI fields employ specialized software or programming languages created specifically for the narrow function required. For example, A.L.I.C.E. utilises a programming language called AIML which is specific to its function as a conversational agent, and has since been adopted by various other developers of, so called, Alicebots. Nevertheless, A.L.I.C.E. is still purely based on pattern matching techniques without any reasoning capabilities, the same technique ELIZA was using back in 1966. This is not strong AI, which would require sapience and logical reasoning abilities.

Jabberwacky learns new responses and context based on real-time user interactions, rather than being driven from a static database. Some more recent chatterbots also combine real-time learning with evolutionary algorithms which optimise their ability to communicate based on each conversation held, with one notable example being Kyle, winner of the 2009 Leodis AI Award. Still, there is currently no general purpose conversational artificial intelligence, and some software developers focus on the practical aspect, information retrieval.

Based on http://en.wikipedia.org/wiki/Chatbots licensed under the Creative Commons Attribution-Share-Alike License 3.0

The Turing test IV – Different versions of the Turing Test and how they matched against each other.

There are at least three primary versions of the Turing test, two of which are offered in "Computing Machinery and Intelligence" and one that Saul Traiger describes as the "Standard Interpretation." While there is some debate regarding whether the "Standard Interpretation" is that described by Turing or, instead, based on a misreading of his paper, these three versions are not regarded as equivalent, and their strengths and weaknesses are distinct.

The Imitation Game
Turing's original game, as we have seen, described a simple party game involving three players. Player A is a man, player B is a woman and player C (who plays the role of the interrogator) is of either sex. In the Imitation Game, player C is unable to see either player A or player B, and can only communicate with them through written notes. By asking questions of player A and player B, player C tries to determine which of the two is the man and which is the woman. Player A's role is to trick the interrogator into making the wrong decision, while player B attempts to assist the interrogator in making the right one.

Sterret refers to this as the "Original Imitation Game Test," Turing proposes that the role of player A be filled by a computer. Thus, the computer's task is to pretend to be a woman and attempt to trick the interrogator into making an incorrect evaluation. The success of the computer is determined by comparing the outcome of the game when player A is a computer against the outcome when player A is a man. If, as Turing puts it, "the interrogator decide[s] wrongly as often when the game is played [with the computer] as he does when the game is played between a man and a woman", it may be argued that the computer is intelligent. and in contrast to Sterrett's opinion, posit that Turing did not expect the design of the machine to imitate a woman, when compared against a human.

The second version appears later in Turing's 1950 paper. As with the Original Imitation Game Test, the role of player A is performed by a computer, the difference being that the role of player B is now to be performed by a man rather than a woman.
"Let us fix our attention on one particular digital computer C. Is it true that by modifying this computer to have an adequate storage, suitably increasing its speed of action, and providing it with an appropriate programme, C can be made to play satisfactorily the part of A in the imitation game, the part of B being taken by a man?"
In this version, both player A (the computer) and player B are trying to trick the interrogator into making an incorrect decision.

The standard interpretation
Common understanding has it that the purpose of the Turing Test is not specifically to determine whether a computer is able to fool an interrogator into believing that it is a human, but rather whether a computer could imitate a human. While there is some dispute whether this interpretation was intended by Turing — Sterrett believes that it was and thus conflates the second version with this one, while others, such as Traiger, do not — this has nevertheless led to what can be viewed as the "standard interpretation." In this version, player A is a computer and player B a person of either gender. The role of the interrogator is not to determine which is male and which is female, but which is a computer and which is a human.

Imitation Game vs. Standard Turing Test
There has arisen some controversy over which of the alternative formulations of the test Turing intended. Sterrett argues that two distinct tests can be extracted from his 1950 paper and that, pace Turing's remark, they are not equivalent. The test that employs the party game and compares frequencies of success 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," noting that Sterrett equates this with the "standard interpretation" rather than the second version of the imitation game. Sterrett agrees that the Standard Turing Test (STT) has the problems that its critics cite but feels that, in contrast, the Original Imitation Game Test (OIG Test) so defined is immune to many of them, due to a crucial difference: Unlike the STT, it does not make similarity to human performance the criterion, even though it employs human performance in setting a criterion for machine intelligence. A man can fail the OIG Test, but it is argued that it is a virtue of a test of intelligence that failure indicates a lack of resourcefulness: 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 non-verbal versions of imitation games.

Still other writers have interpreted Turing as proposing that the imitation game itself is the test, without specifying how to take into account Turing's statement that the test that 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.

Saygin has suggested that maybe the original game is a way of proposing a less biased experimental design as it hides the participation of the computer.

Should the interrogator know about the computer?
Turing never makes clear whether the interrogator in his tests is aware that one of the participants is a computer. To return to the Original Imitation Game, he states only that player A is to be replaced with a machine, not that player C is to be made aware of this replacement. When Colby, FD Hilf, S Weber and AD Kramer tested PARRY, they did so by assuming that the interrogators did not need to know that one or more of those being interviewed was a computer during the interrogation. As Ayse Saygin and others have highlighted, this makes a big difference to the implementation and outcome of the test. Huma Shah & Kevin Warwick, who have organised practical Turing tests, argue knowing/not knowing may make a difference in some judges' verdict. Judges in the finals of the parallel-paired Turing tests, staged in the 18th Loebner Prize were not explicitly told, some did assume each hidden pair contained one human and one machine. Spelling errors gave away the hidden-humans; machines were identified by 'speed of response' and lengthier utterances. In an experimental study looking at Gricean maxim violations that also used the Loebner transcripts, Ayse Saygin found significant differences between the responses of participants who knew and did not know about computers being involved.


Based on http://en.wikipedia.org/wiki/Turing_test licensed under the Creative Commons Attribution-Share-Alike License 3.0

The Turing test III – The Turing Colloquiums and the Loebner Prize.

1990 was the fortieth anniversary of the first publication of Turing's "Computing Machinery and Intelligence" paper, and, thus, saw renewed interest in the test. Two significant events occurred in that year: The first was the Turing Colloquium, which was held at the University of Sussex in April, and brought together academics and researchers from a wide variety of disciplines to discuss the Turing Test in terms of its past, present, and future; the second was the formation of the annual Loebner Prize competition. However, after nineteen Loebner Prize competitions, the contest is not viewed as contributing toward the science of machine intelligence, nor palliating the controversy surrounding the usefulness of Turing's test.

The Loebner Prize provides an annual platform for practical Turing Tests with the first competition held in November, 1991.It is underwritten by Hugh Loebner; the Cambridge Center for Behavioral Studies in Massachusetts, United States organized the Prizes up to and including the 2003 contest. As Loebner described it, one reason the competition was created is to advance the state of AI research, at least in part, because no one had taken steps to implement the Turing Test despite 40 years of discussing it.

The first Loebner Prize competition in 1991 led to a renewed discussion of the viability of the Turing Test and the value of pursuing it, in both the popular press and in academia. The first contest was won by a mindless program with no identifiable intelligence that managed to fool naive interrogators into making the wrong identification. This highlighted several of the shortcomings of Turing test (discussed below): The winner won, at least in part, because it was able to "imitate human typing errors"; the unsophisticated interrogators were easily fooled; and some researchers in AI have been led to feel that the test is merely a distraction from more fruitful research.

The silver (text only) and gold (audio and visual) prizes have never been won. However, the competition has awarded the bronze medal every year for the computer system that, in the judges' opinions, demonstrates the "most human" conversational behavior among that year's entries. Artificial Linguistic Internet Computer Entity (A.L.I.C.E.) has won the bronze award on three occasions in recent times (2000, 2001, 2004). Learning AI Jabberwacky won in 2005 and 2006.

The Loebner Prize tests conversational intelligence; winners are typically chatterbot programs, or Artificial Conversational Entities (ACE)s. Early Loebner Prize rules restricted conversations: Each entry and hidden-human conversed on a single topic, thus the interrogators were restricted to one line of questioning per entity interaction. The restricted conversation rule was lifted for the 1995 Loebner Prize. Interaction duration between judge and entity has varied in Loebner Prizes. In Loebner 2003, at the University of Surrey, each interrogator was allowed five minutes to interact with an entity, machine or hidden-human. Between 2004 and 2007, the interaction time allowed in Loebner Prizes was more than twenty minutes. In 2008, the interrogation duration allowed was five minutes per pair, because the organiser, Kevin Warwick, and coordinator, Huma Shah, consider this to be the duration for any test, as Turing stated in his 1950 paper: " ... making the right identification after five minutes of questioning". They felt Loebner's longer test, implemented in Loebner Prizes 2006 and 2007, was inappropriate for the state of artificial conversation technology. It is ironic that the 2008 winning entry, Elbot, does not mimic a human; its personality is that of a robot, yet Elbot deceived three human judges that it was the human during human-parallel comparisons.

During the 2009 competition, held in Brighton, UK, the communication program restricted judges to 10 minutes for each round, 5 minutes to converse with the human, 5 minutes to converse with the program. This was to test the alternative reading of Turing's prediction that the 5-minute interaction was to be with the computer. For the 2010 competition, the Sponsor has again increased the interaction time, between interrogator and system, to 25 minutes (Rules for the 20th Loebner Prize contest).

In November 2005, the University of Surrey hosted an inaugural one-day meeting of artificial conversational entity developers, attended by winners of practical Turing Tests in the Loebner Prize: Robby Garner, Richard Wallace and Rollo Carpenter. Invited speakers included David Hamill, Hugh Loebner (sponsor of the Loebner Prize) and Huma Shah.

In parallel to the 2008 Loebner Prize held at the University of Reading, the Society for the Study of Artificial Intelligence and the Simulation of Behaviour (AISB), hosted a one-day symposium to discuss the Turing Test, organised by John Barnden, Mark Bishop, Huma Shah and Kevin Warwick. The Speakers included Royal Institution's Director Baroness Susan Greenfield, Selmer Bringsjord, Turing's biographer Andrew Hodges, and consciousness scientist Owen Holland. No agreement emerged for a canonical Turing Test, though Bringsjord expressed that a sizeable prize would result in the Turing Test being passed sooner.

2012 will see a celebration of Turing’s life and scientific impact, with a number of major events taking place throughout the year. Most of these will be linked to places with special significance in Turing’s life, such as Cambridge, Manchester, and Bletchley Park. The Alan Turing Year is coordinated by the Turing Centenary Advisory Committee (TCAC), representing a range of expertise and organisational involvement in the 2012 celebrations. Supporting organisations for the Alan Turing Year include the ACM, the ASL, the SSAISB, the BCS, the BCTCS, Bletchley Park, the BMC, the BLC, the CCS, the Association CiE, the EACSL, the EATCS, FoLLI, IACAP, the IACR, the KGS, and LICS.

Supporting TCAC is Turing100. With the aim of taking Turing's idea for a thinking machine, picturised in Hollywood movies such as Blade Runner, to a wider audience including children, Turing100 is set up to organise a special Turing test event, celebrating the 100th anniversary of Turing's birth in June 2012, at the place where the mathematician broke codes during the Second World War: Bletchley Park. The Turing100 team comprises Kevin Warwick (Chair), Huma Shah (coordinator), Ian Bland, Chris Chapman, Marc Allen; supporters include Rory Dunlop, Loebner winners Robby Garner, and Fred Roberts.


Based on http://en.wikipedia.org/wiki/Turing_test licensed under the Creative Commons Attribution-Share-Alike License 3.0