The contribution that famously carries his name, however, is The Turing Test (which he originally called the imitation game, hence the movie title). In the game he proposes, a human witness would ask questions, through a computer terminal, to a human player and to an “intelligent” computer player. The witness must determine which is the computer. The computer is trying to convince the witness that it is human. Being Turing, he even put numbers on the probability of winning the test,
writing that “an average interrogator will not have more than 70 per cent chance of making the right identification after five minutes of questioning.”
Ever since, people have been making “chat bots” that are good at changing the topic and avoiding the question. Apparently nobody else reads the rest of Turing’s paper, because he gave a great example about the kind of conversation he expected the computer to have:
Interrogator In the first line of your sonnet which reads ‘Shall I compare thee to a summer’s day’, would not ‘a spring day’ do as well or better?
Computer It wouldn’t scan.
Interrogator How about ‘a winter’s day’? That would scan all right.
Computer Yes, but nobody wants to be compared to a winter’s day.
Interrogator Would you say Mr. Pickwick reminded you of Christmas?
Computer In a way.
Interrogator Yet Christmas is a winter’s day, and I do not think Mr Pickwick would mind the comparison
Computer I don’t think you’re serious. By a winter’s day one means a typical winter’s day, rather than a special one like Christmas.
I love when the computer science people use Shakespeare as their test content. Makes my day. I do the same thing :). Consider how much intelligence is in this small example, beyond the ability to form grammatically correct sentences. It needs to understand what sonnet 18 is, first of all, and what it means to compare someone to a summer’s day. It needs to understand the relationship between spring and summer, as well as the purpose of meter in poetry. It needs to understand why you compare someone to a summer’s day but not a winter’s day. It needs to recognize who Mr. Pickwick is, and why you might associate him with Christmas. It needs to understand what Christmas is, and why it is a special day.
In June 2014 there was a big story in the computer science world that a bot has “passed” the Turing Test. Here’s a transcript. You be the judge. Personally I think we’re still a long way away – but imagine how exciting it would be if we ever get there!