Liar! (short story)

Plot summary

A manufacturing fault creates robot RB-34, called Herbie, who has telepathic abilities. The roboticists at U.S. Robots and Mechanical Men investigate how this occurred, while Herbie tells them what others are thinking. Bound by the First Law, the robot deliberately lies when necessary to avoid hurting feelings, especially in romantic matters. When confronted by Susan Calvin—to whom it falsely claimed a coworker was infatuated—the robot experiences an insoluble logical conflict and becomes catatonic.

Adaptations

In 1958, "Liar!" was adapted for the radio show Exploring Tomorrow. A 1966 short film titled El robot embustero was directed by Antonio Lara de Gavilán.

The story was adapted in 1969 for the British television series Out of the Unknown, though only a few short clips of that episode survive. A 1987 Soviet anthology series This Fantastic World featured Boris Plotnikov as RB-34 and Natalya Nazarova as Susan Calvin. BBC Radio 4 broadcast a five-part 15 Minute Drama adaptation of Asimov's I, Robot in February 2017 and December 2025, with this story as episode four.