You may have heard about Baader-Meinhof Phenomenon before. In fact, you probably learned about it for the first time quite recently. If not, then you just might hear about it again very soon. Baader-Meinhof is the phenomenon where one stumbles upon some obscure piece of information—often an unfamiliar word or name—and soon afterwards encounters the same subject again, often repeatedly. Anytime the phrase “That’s so weird, I just heard about that yesterday” would be appropriate, the utterer is hip-deep in Baader-Meinhof.

Most people seem to have experienced the phenomenon at least a few times in their lives, and many people encounter it with such regularity that they anticipate it upon the introduction of new information. But what is the underlying cause? Is there some hidden meaning behind Baader-Meinhof events?

The phenomenon bears some similarity to synchronicity, which is the experience of having a highly meaningful coincidence, such as having someone telephone you while you are thinking about them. Both phenomena invoke a feeling of mild surprise, and cause one to ponder the odds of such an intersection. Both smack of destiny, as though the events were supposed to occur in just that arrangement… as though we’re witnessing yet another domino tip over in a chain of dominoes beyond our reckoning.

Despite science’s cries that a world as complex as ours invites frequent coincidences, intuition tells us that such an explanation is inadequate. Intuition tells us that Baader-Meinhof strikes with blurring accuracy, and too frequently to be explained away so easily. But over the centuries, science has illustrated us that intuition itself is highly flawed, and not to be blindly trusted.

The reason for this is our brains’ prejudice towards patterns. Our brains are fantastic pattern recognition engines, a characteristic which is highly useful for learning, but it does cause the brain to lend excessive importance to unremarkable events. Considering how many words, names, and ideas a person is exposed to in any given day, it is unsurprising that we sometimes encounter the same information again within a short time. When that occasional intersection occurs, the brain promotes the information because the two instances make up the beginnings of a sequence. What we fail to notice is the hundreds or thousands of pieces of information which aren’t repeated, because they do not conform to an interesting pattern. This tendency to ignore the “uninteresting” data is an example of selective attention.

In point of fact, coincidences themselves are usually just an artifact of perception. We humans tend to underestimate the probability of coinciding events, so our expectations are at odds with reality. And non-coincidental events do not grab our attention with anywhere near the same intensity, because coincidences are patterns, and the brain actually stimulates us for successfully detecting patterns, hence their inflated value. In short, patterns are habit-forming.

But when we hear a word or name which we just learned the previous day, it often feels like more than a mere coincidence. This is because Baader-Meinhof 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 subject when we encounter it again in the near future.

How the phenomenon came to be known as “Baader-Meinhof” is uncertain. It seems likely that some individual learned of the existence of the historic German urban guerrilla group which went by that name, and then heard the name again soon afterwards. This plucky wordsmith may then have named the phenomenon after the very subject which triggered it. But it is certainly a mouthful; a shorter name might have more hope of penetrating the lexicon.

However it came to be known by such a name, it is clear that Baader-Meinhof is yet another charming fantasy whose magic is diluted by stick-in-the-mud science and its sinister cohort: facts. But if you’ve never heard of the phenomenon before, be sure to watch for it in the next few days… brain stimulation is nice.

Update: Independent reports indicate that the name “Baader-Meinhof phenomenon” was coined on a discussion thread on the St. Paul Pioneer Press circa 1995. Participants were discussing the sensation, and decrying the lack of a term for it, so someone asserted naming rights and called it “Baader-Meinhof Phenomenon” presumably based on their own experience hearing that moniker twice in close temporal proximity.

The more scientifically accepted name nowadays is “frequency illusion,” but Stanford linguistics professor Arnold Zwicky didn’t coin that term until 2006, over a decade after “Baader-Meinhof” was coined, and around the same time this article was originally written. So both terms are arguably valid.