What Is Frequency Illusion?

Medically Reviewed by Neha Pathak, MD on September 26, 2022
3 min read

After you learn about a new word, notice a new kind of drink, or discover a new medical condition, you may feel that you come across these things more often than you did before. This is known as frequency illusion. Frequency illusion is related to memory. Now that you know about something, it appears to pop up more often.

In reality, your new favorite song may have always been around. But because it’s on your mind, you might start to notice it everywhere and, in turn, think that it’s somehow become more popular.

Experts also call this concept the Baader-Meinhof phenomenon or blue car syndrome. The name “Baader-Meinhof” comes from a militant group in West Germany. After a person read about them in the newspaper, they began to see the terrorist organization over and over again, years after it had been a popular news topic.

Similarly, the blue car syndrome is named after a common situation: When you see a certain car once, you’re more likely to notice that same car again.

This phenomenon is very common. It likely affects everyone at some point in their life. Simply put, frequency illusion happens because you pay more attention to things that have recently become important to you.

There are two parts to the frequency illusion. First, you’ll believe that something has begun to show up more often. Then, you’ll convince yourself that the word, concept, or other thing didn’t show up as much as it does now, called confirmation bias. The frequency hasn’t actually gone up, but your brain has convinced you that it has.

While there aren’t many studies on frequency illusion, the concept is very similar to something called “working memory-driven attentional capture.” This explains how your attention is guided. When you hold a certain idea in your mind, your attention naturally goes toward that thing - without you even noticing.

Frequency illusion works with your voluntary and involuntary attention. Voluntary attention helps you select and focus on information that’s important to your current task. Involuntary attention happens when something else captures your attention away from that task.

This is related to how we’ve evolved. Our minds must respond to things around us in order to be safe. But we also need to tune certain things out if we want to effectively complete a task. Attention is important for learning and memory. If you don’t pay attention to something, you won’t remember it. So if you just learned about something new for the first time, chances are that you’ll begin to see it more simply because you’re now aware of it.

For most people, frequency illusion won’t lead to any major effects. It’s simply an interesting phenomenon. But for others, frequency illusion can lead to serious outcomes.

For example, if you work within the criminology field, your attention may be brought to a specific suspect. Your mind will then be more inclined to pay attention to that person when new information comes out. This could be helpful to the case and lead a detective to the right suspect. But it can also be harmful. If a detective’s mind is focused on one person, they may miss other key evidence.

Similarly, if you work in the medical field, you may have recently learned about a new condition. Because your focus is on this disease, you might be more likely to diagnose more people based on their symptoms. Frequency illusion in this case could be helpful because you’re more aware of this new condition. But it could also cause you to skip over other similar conditions and misdiagnose someone.

In other cases, if you have certain psychological disorders, frequency illusion may worsen your condition. If you have schizophrenia, the confirmation bias from frequency illusion can cause you to confirm your own suspicions. If you focus on a specific delusion that you have from schizophrenia, frequency illusion may convince you that something is real when it’s not.

Overall, this phenomenon shows you how much information your brain actually takes in at any given moment. Most of the time, you aren’t even aware of it. This concept explains why we notice certain things more than others once our attention is fixated on something.