The state of the art in machine conversation: HAL's still pure Hollywood

Anyone who has followed science fiction will remember the soothing voice of HAL, the computer that methodically killed all but one of the crew of the space ship it controlled. Perhaps the most compelling scene in the movie is the conversation that HAL had with the lone survivor as he inactivated the computer. The scene was notable largely because the conversation seemed so normal; HAL's end of it seemed positively human. A perspective in today's issue of Science takes a look at the prospects of creating computers that can mange this feat, and engage in natural-sounding conversations.