Frequency illusion

Frequency illusion, also known as the Baader–Meinhof phenomenon, is a cognitive bias in which, after noticing something for the first time, there is a tendency to notice it more often, leading someone to believe that it has a high frequency (a form of selection bias).[1][2][3] It occurs when increased awareness of something creates the illusion that it is appearing more often.[4] Put plainly, the frequency illusion is when "a concept or thing you just found out about suddenly seems to crop up everywhere."[5] It was named after an incidence of frequency illusion in which the Baader–Meinhof Group was mentioned.[6]

The Baader–Meinhof phenomenon was originally noticed by a Terry Mullen, who in 1994 wrote a letter to a newspaper column in which he mentioned that he had first heard of the Baader–Meinhof Group, and shortly thereafter coincidentally came across the term from another source. After the story was published, readers continued to submit their own experiences of similar events, and the phenomenon was named the Baader–Meinhof phenomenon.[5]

The term "frequency illusion" was coined in 2006 by Arnold Zwicky, a professor of linguistics at Stanford University and Ohio State University. Arnold Zwicky considered this illusion a process involving two cognitive biases: selective attention bias (noticing things that are salient to us and disregarding the rest) followed by confirmation bias (looking for things that support our hypotheses while disregarding potential counter-evidence).[7] It is considered mostly harmless, but can cause worsening symptoms in patients with schizophrenia.[4] The frequency illusion may also have legal implications, as eye witness accounts and memory can be influenced by this illusion.[4]