Have you ever learned a new word, one that you swear you've never heard before, only to find it popping up throughout your daily life for a few days after? It’s like the word is haunting you, or that the word didn’t exist at all before you learned it. Well, turns out that’s called the Baader-Meinhof phenomenon, and it all comes down to your brain playing tricks on you.

The Baader-Meinhof phenomenon is actually a term for 'frequency illusion', a type of cognitive bias your mind creates. To understand this, you need to know a little about cognitive bias as a whole. Though there's a whole lot of nuisances caused by cognitive bias, in short, it’s when your mind deviates from normal, rational thought and starts to make up patterns based off of nonsense.

John Donovan from Mother Nature Network summarises this elegantly:

"Example: Hindsight bias (also known as the "I knew it all along" bias) is the tendency to think that, looking back on an event, we should have seen it coming - even though there may be no rational reason that we actually should have known what was going to happen."

So what about frequency illusion? Well, the term was coined in 2006 by Arnold Zwicky, a linguist from Stanford University, who claims that frequency illusion is, in fact, two different processes happening at the same time: selective attention and confirmation bias.

The first process, selective attention, comes about when you learn anything new. Basically, when you learn something new, it stays fresh in your mind - you’re paying more attention to it than other things. Because of this, you see it more often when going about your daily life.

However, this very simple, logical process is amped up by confirmation bias, which is a cognitive bias that makes you "search for or interpret information in a way that confirms one's preconceptions, leading to statistical errors", reports ScienceDaily.

This means that your mind is on the look-out for newly learned information because it’s still super fresh and interesting to you. At the same time, your mind sees these new words everywhere, thinks that it's weird, and tries to make it fit into some rational system.

In other words, because the information is new, you suddenly force yourself to believe that it's new to everyone and has suddenly popped up, when in reality, you’ve just stopped ignoring it.

The name Baader-Meinhof phenomenon actually started as a meme in 1994. Since frequency illusion was coined in 2006, people sort of just came up with a term to describe the weird feeling without having the science behind it. According to Pacific Standard:

"Baader-Meinhof phenomenon was invented in 1994 by a commenter on the St. Paul Pioneer Press' online discussion board, who came up with it after hearing the name of the ultra-left-wing German terrorist group twice in 24 hours. The phrase became a meme on the newspaper’s boards, where it still pops up regularly, and has since spread to the wider Internet."

So there you have it. You actually see new words more often and believe there’s some weird pattern at work because your mind is trying to make sense of new information. It just so happens that most of it is made up.