Frequency Illusion

We tend to notice things more often after we've first become aware of them, and then assume those things are more common than they actually are. The world hasn't changed. Our attention has.

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Now, back to the Frequency Illusion ⏬

What if the trend your team keeps talking about isn't actually a trend... and your brain has been quietly manufacturing evidence for it this whole time?

You're in a design review, and someone drops a term you've never heard before.

You nod along, look it up after the meeting, and move on.

Later, you're browsing your feed and see a reference to the same term.

Next morning, doomscrolling LinkedIn, you see it again.

By the end of the week, it's everywhere. Every app. Every conversation. Every post.

But here's the thing: it was always there. You just couldn't see it until somebody gave you the name.

That's the frequency illusion. And it's not just a fun quirk of perception.

The same mechanism runs quietly in the background every time your team decides:

⇢ What counts as a trend
⇢ What qualifies as a problem
⇢ What's worth putting on the roadmap

And the worrying part is that It feels exactly like insight.

In this week's Cognition Catalog, we break down:

⇢ What the frequency illusion actually is (and why it has two names)
⇢ How selective attention and confirmation bias team up to distort your judgment
⇢ Why "we keep hearing this" might be the sketchiest thing on your roadmap
⇢ What you can do to filter your own filter

Remember: Frequency in your head is not frequency in the real world.

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The Frequency Illusion: You... May 8 · Beyond UX Design 12:30   ​

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The Frequency Illusion has two names, and the story behind the more colorful one is pretty good.

In 1994, a man named Terry Mullen wrote a letter to the St. Paul Pioneer Press describing how, after hearing about the Baader-Meinhof Gang for the first time, they were a German terrorist group from the 1970s, he encountered references to it two more times within 24 hours. The newspaper published his letter. The name stuck. And for years, the Baader-Meinhof phenomenon spread across the internet as informal shorthand for this type of experience.

It wasn’t until 2005 that Stanford linguistics professor Arnold Zwicky gave it the more descriptive label that we tend to use today: the Frequency Illusion. Zwicky was writing about language patterns, but the observation applied to everything. The Oxford English Dictionary later recognized the term, defining the Frequency Illusion as “a quirk of perception whereby a phenomenon to which one is newly alert suddenly seems ubiquitous.”

Read that definition a second time. Newly alert. Not newly present.

So why does it happen?

Zwicky attributed the illusion to two psychological processes working together: selective attention and confirmation bias. The first one lights the fire while the second one keeps it burning.

Selective attention is the brain’s triage system. It can’t process everything, so it decides what matters and flags it for closer monitoring. Once something earns that flag, your brain keeps scanning for it without you consciously deciding to. The new UI pattern you just learned about is now on your brain’s radar. So every app you open starts registering it.

Then confirmation bias kicks in. Once you’ve started noticing a specific stimulus, you notice it more — and that noticing feels like confirmation that it’s everywhere, even though the actual frequency hasn’t changed.

One more thing worth knowing: the Frequency Illusion often travels alongside what Zwicky called the Recency Illusion. The recency illusion is the belief that something you’ve only recently noticed must also be recent. It’s a close cousin that compounds the problem. Not only do we think a thing is everywhere, we also assume it just started showing up.

When we put these two effects together, it can make a brand-new idea feel like an emerging trend, a single customer complaint feel like a widespread pattern, and a recently discussed feature feel like the most pressing item on the roadmap.

The Frequency Illusion isn’t a failure of intelligence; it’s more of a quirk of attention. Our brains are wired to prioritize novelty and look for patterns — mostly useful, until a new piece of information hijacks our filter and warps our sense of how common, important, or urgent something actually is.

The Frequency Illusion sounds harmless enough when it's about Inter or a UI pattern you just discovered. But the same mechanism runs quietly in the background of how product teams read their environment, and it can distort judgment in ways that are hard to spot because they feel exactly like insight.

The most direct place it shows up is in design critique. A designer learns a new term, say, "affordance" or "progressive disclosure," and suddenly they're seeing violations of it everywhere: In their own product. In competitor apps they've been auditing for months. In designs they reviewed and approved months ago. The designs didn't change; we just got a new word for something that was always there.

The same thing happens after conferences. Someone comes back with a specific pattern or principle they encountered for the first time, and suddenly it's visible everywhere: in products they use daily, in the team's own design system, in research findings they've been sitting on for weeks. The pattern was always present. It just didn't have a name until now.

The tricky part is that this can feel exactly like professional growth. Learning to see things you couldn't see before is genuinely valuable. Just be careful not to mistake newly-named for newly-present, and treat a pattern you just learned to recognize as more widespread, more urgent, or more significant than the evidence actually supports.

Building the habit of asking "was this always here, or did we just get the right filter?" creates enough friction between noticing and concluding to keep the team honest.

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🎯 Here are some key takeaways

1️⃣ Understand that attention is not neutral: Your brain doesn't show you the world as it is, it shows you the world it thinks it needs to look for. Once something new enters your awareness, your brain actively works to surface more of it. Every new thing you learn is also changing what you see next. Building that awareness into how you consume research, feedback, and competitive data is the first step toward filtering your own filter.

2️⃣ Watch for shared attention bias on teams: When an entire team gets primed on the same idea at the same time, the Frequency Illusion starts to scale. Everyone starts noticing the same signals, in the same direction, with the same confidence. What feels like team alignment might actually be team-wide tunnel vision. Rotating who introduces topics, who synthesizes research, and who challenges assumptions helps keep the team's collective attention from collapsing into a single focus.

3️⃣ Don't let airtime substitute for evidence: The amount of time a topic has been discussed in meetings is not a measure of its importance. Before treating a recurring theme as validated, trace it back: where did it come from? How many independent sources actually raised it? Has it been tested against data, or has it mostly been referenced in conversation? Frequency in the room is not frequency in the world.

4️⃣ Create deliberate distance between discovery and decision: The Frequency Illusion is strongest right after something new is introduced. That’s when novelty is still fresh and the brain is actively scanning for confirmation. Waiting before acting on a new pattern isn't indecision; think of it more as discipline. Building in a review step between "we noticed something" and "we're prioritizing this" gives the initial spike of selective attention time to settle before it shapes the roadmap.

5️⃣ Surface what you're not seeing: Think of last week’s episode on survivorship bias. Most prioritization conversations focus on what's showing up. The Frequency Illusion should prompt an equal focus on what's being filtered out. Regularly ask: what problems haven't come up lately? What users haven't we heard from? What signals aren't making it into our conversations? The absence of attention isn't the same as the absence of a problem. It might just mean nobody primed the filter.

Learn more about the Frequency Illusion!

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