"Gaslighting is a form of psychological abuse. It uses persistent denials of fact which, as they build up over time, make the victim progressively anxious, confused, and unable to trust his or her own memory and perception... The term was coined from the 1940 film Gaslight and its 1944 remake in which changes in gas light levels are experienced several times by the main character. The classic example in the film is the character Gregory using the gas lamps in the attic, causing the rest of the lamps in the house to dim slightly; when Paula comments on the lights' dimming, she is told she is imagining things." - Wikipedia
A method also used to great effect on the Wordie earworm page, where certain people can't hear accompanying music. ;-)
Love the etymology of this word.
"Gaslighting is a form of psychological abuse. It uses persistent denials of fact which, as they build up over time, make the victim progressively anxious, confused, and unable to trust his or her own memory and perception... The term was coined from the 1940 film Gaslight and its 1944 remake in which changes in gas light levels are experienced several times by the main character. The classic example in the film is the character Gregory using the gas lamps in the attic, causing the rest of the lamps in the house to dim slightly; when Paula comments on the lights' dimming, she is told she is imagining things."
- Wikipedia