Out of the Unknown: Liar!

"Liar" is the second episode of season three of Out of the Unknown. It first aired on BBC2 on January 14th, 1969. "Liar!" is based on a short story by famed science fiction author Isaac Asimov and first appeared in the May, 1941 issue of Astounding Science Fiction. The story has also been reprinted in various Asimov anthologies including I, Robot and The Complete Robot.

Synopsis
The plot centers around robot RB34, also known as "Herbie", who possesses a positronic brain that evolves and enables him to re-interpret the First Law of Robotics. The First Law implicitly states, "A robot may not harm a human being or, through inaction, allow a human being to come to harm". Herbie determines that humans may experience emotional harm when faced with certain truthful situations, so he adapts his behavior and begins lying to his superiors, in particular, Doctor Susan Calvin and Doctor Lanning.

Notes & Trivia

 * Doctor Susan Calvin is a recurring character who has appeared in several Isaac Asimov stories.


 * Only a few clips and tele-snaps of this episode are known to still exist. It was the practice of the BBC to wipe their episodes after their initial broadcasts.