Start looking for a new car one day and pretty soon you are seeing examples of that car everywhere you look. Same thing happens if you’ve just noticed a particular breed of dog on a walk in the park, soon afterwards you are seeing that dog breed everywhere you go. The effect is called a frequency illusion.
Your brain neatly filters out all but examples of the object you have seen. This is a by-product of the brain being biased towards pattern recognition. Great as a learning strategy but it can cause this illusion.
As an example, we notice a silver Honda Accord and when we notice another silver Honda Accord the brain automatically promotes that second example as it forms the start of a pattern. We ignore the thousands of other cars we see on the roads in favour of the more interesting “pattern” of the two Hondas. It even seems like they have been spotted improbably close to each other thanks to the filtering out of the other cars, a type of selective attention.
Frequency illusion is amplified by the recency effect, a cognitive bias that inflates the importance of recent stimuli or observations. This increases the chances of being more aware of the object when we encounter it again in the near future. So it really does seem like having noticed one Honda that there are suddenly lots of them on the road everywhere you go.
The frequency illusion is also known as the Baader-Meinhof phenomenon, a phrase that was first coined in 1986 by Terry Mullen, a reader of the St. Paul Pioneer Press, a Minnesota newspaper that runs a daily column called “Bulletin Board” to which readers submit interesting anecdotes. Terry submitted a story about how he first heard the name of the ultra-left-wing German terrorist group of the 1970s twice in 24 hours. Today, all similar stories are published under the heading Baader-Meinhof Phenomenon.
But seeing two sets of temporary traffic lights around road works on my commute into work is actual hard fact rather than a frequency illusion. Honestly, they were really there! You’ve got to ask, how are road works planned? Why does someone think it’s ok to cause chaos on two parts of the same road at the same time? Or is it just that my brain only sees those two sets of lights and has conveniently ignored all of the others? Andreas Baader and Ulrike Meinhof have a lot to answer!