You learn about a new word, concept, or product. Then, suddenly, you see it everywhere—in articles, conversations, advertisements. It feels like the universe is sending you a message.
It’s not.
You’re experiencing the Baader-Meinhof phenomenon, also called the frequency illusion. And it reveals something fascinating about how your brain filters reality.
The thing you’re noticing isn’t appearing more often. You’re just finally paying attention.
What Is the Baader-Meinhof Phenomenon?
Baader-Meinhof phenomenon (also called frequency illusion) is the experience of encountering something frequently right after learning about it for the first time.
The experience:
- You learn about X (a word, band, car model, concept)
- Immediately afterward, you encounter X multiple times
- It feels like X suddenly appeared everywhere
- In reality, X was always there—you just didn’t notice
Etymology:
The name “Baader-Meinhof” comes from a 1994 incident:
- A commenter on a Minnesota newspaper’s online discussion board mentioned the Baader-Meinhof Gang (a German terrorist group)
- Immediately after, he noticed references to the group appearing repeatedly
- He dubbed this experience the “Baader-Meinhof phenomenon”
The name stuck, though the phenomenon had been studied for decades under other names:
- Frequency illusion
- Recency illusion
- Selective attention bias
(first encounter) A->>A: 'X' becomes
salient A->>P: Heightened attention
to 'X' Note over A,P: Selective attention activated P->>M: Notice 'X'
repeatedly M->>M: 'X is everywhere!'
(Frequency illusion) Note over E,M: 'X' was always there—you just started noticing
The Two Mechanisms Behind It
The Baader-Meinhof phenomenon results from two cognitive processes working together:
1. Selective Attention
Your brain cannot process all sensory information.
At any moment:
- Millions of stimuli compete for attention
- Your brain filters out 99.9% of them
- Only salient information reaches conscious awareness
What determines salience?
- Novelty: New information stands out
- Relevance: Information related to current goals or interests
- Emotional significance: Threats, rewards, personally meaningful content
After learning about X:
- X becomes novel and relevant
- Your attentional filter now flags X as important
- You notice X when previously you’d have ignored it
Example:
Before learning about “confirmation bias”:
- The phrase appears in an article → Your brain filters it out (not relevant)
After learning about “confirmation bias”:
- The phrase appears in an article → Your attention snaps to it (now relevant!)
- You think: “Wow, I’m seeing this everywhere now!”
But the frequency hasn’t changed. Your attention has.
Millions of stimuli] --> B[Attentional Filter] B --> C{Is it salient?} C -->|No| D[Filtered out
Never reaches
consciousness] C -->|Yes| E[Passes to
conscious awareness] F[Recent Learning:
'X' becomes salient] --> B E --> G[You notice 'X'
repeatedly] style A fill:#4c6ef5 style B fill:#ae3ec9 style F fill:#ffd43b style G fill:#51cf66
2. Confirmation Bias
Once you notice X, you start collecting evidence that X is everywhere.
Confirmation bias: The tendency to search for, interpret, and remember information that confirms your existing beliefs.
How it works in Baader-Meinhof:
You think: “I’ve been seeing this word a lot lately.”
Your brain: “Let’s find more examples to confirm this pattern.”
Result:
- You notice instances of X (confirmations)
- You ignore or forget times you don’t see X (disconfirmations)
- You remember the hits, forget the misses
This creates a feedback loop:
- Selective attention makes you notice X
- Confirmation bias makes you remember noticing X
- You conclude X is appearing more frequently
- This belief reinforces your attention to X
- Loop continues
Notice 'X'] B --> C[Confirmation Bias:
Remember instances
of 'X'] C --> D[Belief: 'X is
everywhere now'] D --> E[Strengthened
attention to 'X'] E --> B style A fill:#4c6ef5 style B fill:#ae3ec9 style C fill:#ffd43b style D fill:#ff6b6b style E fill:#51cf66
Real-World Examples
1. Buying a New Car
Classic example:
You buy a Honda Civic. Suddenly, you see Honda Civics everywhere. Every parking lot, every highway.
Reality: The number of Honda Civics didn’t increase. You just became attentive to them.
Before buying: Your brain filtered out Civics as irrelevant After buying: Civics are now personally significant → Selective attention → You notice them
Bonus confirmation bias: You remember all the Civics you see, forget all the Toyotas, Fords, and Chevys you didn’t pay attention to.
2. Pregnancy
New parents report this constantly:
“As soon as we got pregnant, suddenly everyone else is pregnant too!”
Reality: ~10-15% of women aged 15-44 are pregnant at any time (US stats). That hasn’t changed.
What changed: Pregnancy is now personally relevant. Your attentional filter now flags pregnant women, strollers, baby stores.
Result: You notice what was always there.
3. Learning New Words
You encounter a word like “ubiquitous.”
Within a week, it appears in:
- Three different articles
- A podcast
- A conversation
Feels like: The universe is teaching you this word.
Reality: “Ubiquitous” appears frequently in educated writing. You were filtering it out before. Now you’re not.
4. Tech and Startups
You read about a startup building AI tools for X.
Suddenly:
- Y Combinator has three similar companies
- LinkedIn is full of posts about X
- Your Twitter feed is discussing X
Feels like: X is the hot new trend that just emerged.
Reality: X has been developing for months/years. You just became aware of the space, so now you notice everything related to it.
This happens constantly in tech:
- “Everyone’s pivoting to AI!” (No, you just started paying attention)
- “Rust is taking over!” (No, Rust adoption has been steady; you just joined Rust Twitter)
5. Name Coincidences
You meet someone named “Ezra.” Then you hear the name three more times that week.
Feels like: Cosmic synchronicity.
Reality: Ezra is a reasonably common name. You’ve been filtering it out. Now you notice it.
People often interpret this as:
- “The universe is sending me signs”
- “I’m meant to pay attention to Ezra-related things”
Actual explanation: Selective attention + confirmation bias.
The Neuroscience: Attention and Salience
Your brain’s attention system has limited capacity.
Key brain regions:
1. Reticular Activating System (RAS)
Function: Filters sensory information, decides what reaches consciousness
How it works:
- Located in the brainstem
- Receives input from all sensory systems
- Flags information as important or ignorable
- Only “important” information reaches cortex
What makes something important to RAS?
- Novelty (new stimulus)
- Personal relevance (related to current goals)
- Survival significance (threats, rewards)
After learning about X:
- RAS marks X as novel and relevant
- X now passes through the filter
- You consciously notice X
Before learning about X:
- RAS filtered X out as noise
- X never reached consciousness
- You were blind to X
2. Prefrontal Cortex (PFC)
Function: Top-down control of attention
How it works:
- Sets goals and priorities
- Biases attention toward goal-relevant information
- Suppresses irrelevant distractions
When you learn about X:
- PFC temporarily elevates X’s priority
- Attention is biased toward X
- Other information is suppressed
3. Hippocampus and Memory
Function: Encodes and retrieves memories
How confirmation bias enters:
- You notice X → Hippocampus encodes the memory
- You don’t notice Y → No memory formed
- Later, you recall noticing X multiple times
- You have no memory of not noticing Y (because you didn’t encode those moments)
Result: Biased memory creates the illusion of increased frequency.
Filter] B --> C{Novel or
Relevant?} C -->|No| D[Blocked] C -->|Yes| E[Passes to Cortex] E --> F[Prefrontal Cortex:
Goal-directed
attention] F --> G[Conscious
Awareness] G --> H[Hippocampus:
Memory
Encoding] H --> I[Recalled later:
'I keep seeing X!'] style A fill:#4c6ef5 style B fill:#ae3ec9 style E fill:#51cf66 style I fill:#51cf66
Why This Matters: Practical Implications
1. Market Research and Trend Analysis
Danger: Mistaking selective attention for real trends.
Scenario:
- You read about “Web3” in a tech blog
- Suddenly, you see Web3 everywhere
- You conclude: “Web3 is exploding! We need to pivot!”
Reality check:
- Was Web3 actually growing, or did you just start noticing it?
- Look at objective metrics: search volume, funding data, user adoption
- Don’t confuse your attention with market reality
2. Investing and Finance
Danger: Confirmation bias reinforcing Baader-Meinhof.
Scenario:
- You buy Tesla stock
- You notice positive Tesla news everywhere
- You conclude: “My investment thesis is validated!”
Reality:
- You’re selectively attending to confirmatory information
- Negative news is filtered out or dismissed
- This creates overconfidence
Solution: Actively seek disconfirming evidence. “What would make my thesis wrong?”
3. Medical Students’ Disease
Classic phenomenon:
Medical students learn about a disease → Immediately experience symptoms → Convince themselves they have it.
Mechanism: Baader-Meinhof + hypochondria
- Learn about symptom X
- Become hyperaware of bodily sensations
- Notice normal variations that match X
- Interpret them as disease
Example:
- Learn about multiple sclerosis (symptom: tingling)
- Notice normal tingling in hand
- “Oh no, I have MS!”
Reality: Normal bodily sensations that were always there, now salient.
4. Conspiracy Theories
Baader-Meinhof fuels conspiratorial thinking:
Scenario:
- Learn about a conspiracy theory (e.g., “chemtrails”)
- Start noticing contrails in the sky
- “I’m seeing chemtrails everywhere! The conspiracy is real!”
Reality:
- Contrails are common and were always there
- Selective attention makes you notice them
- Confirmation bias makes you remember them
- Feedback loop reinforces belief
Dangerous because: The subjective experience (seeing it everywhere) feels like objective evidence (it’s actually everywhere).
5. Social Media Echo Chambers
How Baader-Meinhof amplifies filter bubbles:
You engage with content about X:
- Algorithm shows you more X
- You notice X more in your feed
- You think: “Everyone’s talking about X!”
Reality:
- You’re in a curated bubble
- The algorithm is feeding selective attention
- Confirmation bias reinforces the bubble
Result: Massively distorted perception of what “everyone” cares about.
How to Recognize and Counter It
1. Awareness Is the First Step
Simply knowing about Baader-Meinhof helps.
When you think: “I’m seeing this everywhere suddenly…”
Pause and ask: “Or did I just start noticing?”
2. Look for Objective Data
Don’t trust your subjective impression.
Instead:
- Google Trends: Has search volume actually increased?
- Historical data: Check if the thing existed before you noticed it
- Third-party metrics: What do objective sources say?
Example:
- You think: “Everyone’s talking about Rust now!”
- Check: Google Trends shows Rust interest has been steady for years
- Conclusion: You just started paying attention
3. Seek Disconfirming Evidence
Actively look for evidence that contradicts your impression.
You think: “I’ve been seeing red cars everywhere.”
Test: Count cars. How many are red vs. other colors?
Result: Often, you’ll find the frequency is normal—you were just noticing red cars selectively.
4. Keep a Log
Write down when you notice X.
Also write down:
- When you don’t notice X (but expected to)
- Other things you noticed instead
This creates a more balanced record and counters confirmation bias.
5. Check the Base Rate
How common is X in general?
You think: “I’ve seen three people named ‘Liam’ this week!”
Check: Liam is the #1 most popular baby name in the US (2023). Seeing three Liams is statistically expected.
Often, what feels like a surge is just normal frequency you’re now noticing.
The Positive Side: Learning and Pattern Recognition
Baader-Meinhof isn’t always bad. It’s actually a feature of effective learning.
1. Accelerated Learning
When you learn a new concept, Baader-Meinhof helps you:
- Notice it in multiple contexts
- See real-world applications
- Encode it more deeply through repetition
Example:
- Learn about “confirmation bias” in a psychology class
- Notice it in news articles, arguments, your own thinking
- Each instance reinforces your understanding
This is learning in action.
2. Pattern Recognition
Selective attention helps you identify meaningful patterns.
In data science:
- Learn about a statistical pattern
- Start noticing it in datasets
- This is genuine pattern recognition, not illusion
The key: Verify with data, not just subjective impression.
3. Building Expertise
Experts notice things novices don’t.
A chess master sees patterns on the board a novice misses.
This is selective attention trained through experience:
- Relevant patterns become salient
- Irrelevant information is filtered
- Expert perception is faster and more accurate
Baader-Meinhof is the early stage of this process.
The Broader Principle: Perception Is Selective
The Baader-Meinhof phenomenon reveals a fundamental truth:
You don’t perceive reality objectively. You perceive selectively, based on what your brain deems important.
Implications:
1. Attention is a spotlight:
- You illuminate some things, leave others in darkness
- What you notice depends on where you point the spotlight
- Moving the spotlight changes your reality
2. “Reality” is partially constructed:
- You don’t see the world as it is
- You see the world as your attention shapes it
- Different people, different spotlights, different realities
3. Your beliefs shape your perceptions:
- What you believe is important determines what you notice
- What you notice reinforces what you believe
- This creates self-reinforcing loops
Everything exists] --> B[Attentional Filter:
Selective Attention] B --> C[Subjective Perception:
What you notice] C --> D[Memory:
What you remember] D --> E[Belief:
'X is everywhere'] E --> B F[Learning/Relevance] --> B style A fill:#4c6ef5 style B fill:#ae3ec9 style C fill:#51cf66 style E fill:#ff6b6b
The Takeaway
The Baader-Meinhof phenomenon isn’t magic or cosmic synchronicity. It’s your brain’s attention system working as designed.
You experience frequency illusion because:
- Selective attention: Your brain filters reality based on relevance
- Confirmation bias: You remember hits, forget misses
- Limited capacity: You can’t notice everything, so you notice what matters to you
This reveals:
- Perception is not passive recording—it’s active filtering
- What you notice depends on what you care about—attention follows relevance
- Your subjective experience can be misleading—it feels like X is everywhere, but objective data may disagree
Next time you think, “I’m seeing this everywhere suddenly!”:
Pause. Ask yourself: “Did the frequency actually increase, or did I just start paying attention?”
Usually, it’s the latter.
The world didn’t change. Your attention did.
This is part of the Brain Series. The Baader-Meinhof phenomenon shows how selective attention and confirmation bias shape your perception—creating the illusion that coincidences are more than coincidence.