Imitation brains

WHEN HE SUGGESTED a test based on a written conversation to determine whether a computer is intelligent, Alan Turing was confident a machine would pass the exam within 50 years. By that time, in his view, an average interrogator would have no more than a 70 per cent chance of choosing human or computer correctly after five minutes of questioning. After almost 65 years of work, most artificial intelligence (AI) researchers remain unconvinced by any of the challengers' performances so far, including the efforts this year of one team's chatbot to emulate the text and email characteristics of a teenager from Ukraine.