In 1966, he published a comparatively simple program called ELIZA, named after the ingenue in George Bernard Shaw's Pygmalion, which performed natural language processing. Driven by a script named DOCTOR, it was capable of engaging humans in a conversation which bore a striking resemblance to one with an empathic psychologist. Weizenbaum modeled its conversational style after Carl Rogers, who introduced the use of open-ended questions to encourage patients to communicate more effectively with therapists.