Joseph Weizenbaum developed the ELIZA program at MIT in 1966, and it was one of the earliest AI programs. This famous natural language understanding program is an important milestone in the AI field, and it was named after the character “Eliza” in the musical My Fair Lady. It simulated a conversation between a patient and a psychotherapist, with the program using the person’s response to shape its reply. The interaction was between the computer program and a user sitting at an electric typewriter, with the user typing and the computer program responding. The program convinced several users that it had real understanding and that it was an empathic psychotherapist. Weizenbaum was shocked to discover that so many users were taking his program seriously and that they were sharing their most private thoughts with the machine. He became an advocate of social responsibility in science and a leading critic of AI research.