It was first described in 1994 in a letter to _The Skeptic Magazine_. The German journalist, Terry Mullen called it the "French toast problem". He had heard the term for the first time in a diner after ordering it himself. In the following weeks, Mullen started noticing mention of the item on food menus, in a newspaper article, and a conversation he overheard.
The phenomenon doesn't only relate to things you have recently learned about, but can relate to anything you pay attention to. For instance, if you buy a new car and then suddenly start noticing the same make and model everywhere.
Psychologists believe the phenomenon is attributed to a type of selective attention: once you have acquired new knowledge, your mind is primed to notice anything related to it.
A 2017 study in _Perception_ found that people who were given information about an obscure animal called a "Snark", which supposedly lived in New Zealand, later misremembered the information as coming from a TV documentary.
However, another 2018 study in _Consciousness and Cognition_, found that the effect may not be explained by simple misremembrance. Instead, it may have something to do with people trying to recall obscure facts by looking them up online, which reinforces their memory of the fact.
The phenomenon bears the name of the left-wing West German terrorist group, the Red Army Faction (Rote Armee Fraktion), also known as the Baader-Meinhof Gang. The group was prominent during the 1970s. One of its members, Ulrike Meinhof, was involved in numerous violent actions and wrote revolutionary articles for the organisation's newspaper, "The Red Army Faction".
In the 1990s, a German journalist, Matthias Nölte, wrote an essay detailing his experience of the phenomenon, in which he repeatedly came across the name of the Baader-Meinhof Gang after it had been mentioned to him for the first time. He called the phenomenon the "Baader-Meinhof Phenomenon" in reference to the frequency with which the group's name appeared to him after he learned about it.
