Keywords: Baader-Meinhof phenomenon, frequency illusion, selective attention, confirmation bias, recency bias, pattern recognition brain, why you notice things everywhere, cognitive bias psychology, priming effect, Baader-Meinhof effect explained
Tags: #baader-meinhof-phenomenon #frequency-illusion #cognitive-bias #selective-attention #psychology
You learn a new word and hear it three times that week. You buy a red car and suddenly notice red cars everywhere. You read an article about a company you had never heard of, and then see it mentioned in two unrelated conversations the next day. You wonder: is this a coincidence? Has something changed? Is the universe sending signals?
None of the above. What has changed is your attention. The word was always there. The red cars were always on the road. The company was always being discussed. You simply were not filtering for them before, and now you are. This is the Baader-Meinhof phenomenon -- and once you understand it, you will notice it everywhere.
The Origin of the Name
The Baader-Meinhof phenomenon gets its peculiar name from a 1994 comment thread on the St. Paul Pioneer Press website. A reader named Terry Mullen wrote that he had heard the name of the German left-wing terrorist group "Baader-Meinhof" for the first time, and then encountered it again just a day or two later in a completely unrelated context. He described the experience as a "Baader-Meinhof phenomenon," half-jokingly proposing a name for this familiar but oddly uncanny experience.
The post resonated. Other readers recognized exactly the same experience from their own lives. The name stuck. For years it circulated informally before finding its way into wider discussion -- helped along, appropriately, by the very mechanism it describes: once people encountered the term, they began noticing the phenomenon being described.
The more formal name for the same cognitive experience is the frequency illusion, a term coined by Stanford linguist Arnold Zwicky in 2006. In a blog post, Zwicky defined it simply: "the illusion in which a word, name, or other thing that has recently come to one's attention suddenly seems to appear with improbable frequency shortly afterwards."
Zwicky was careful to emphasize that the "illusion" is not about perception being hallucinated but about a genuine change in what reaches conscious awareness. The frequencies in the external world have not changed; what has changed is the internal filter determining what gets brought into consciousness. This distinction — between objective frequency and subjectively perceived frequency — is at the heart of the phenomenon.
What Is Actually Happening
The Baader-Meinhof phenomenon is not mysterious once you understand two ordinary cognitive mechanisms: selective attention and confirmation bias.
Selective Attention
The human brain receives an enormous quantity of sensory input every second -- visual, auditory, tactile, olfactory information flooding in from the environment simultaneously. The vast majority of this input never reaches conscious awareness. Your brain continuously filters the incoming stream, directing conscious attention toward what has been flagged as relevant and filtering out what has been deemed irrelevant.
This filtering happens before consciousness. You do not decide not to consciously notice the ambient noise of air conditioning, the texture of the chair you are sitting on, or the color of every car that passes your window. Your brain makes that filtering decision before it reaches awareness.
When you learn something new -- a word, a brand, an idea, a person's name -- that item gets marked as recently relevant in your cognitive priority queue. The marking is essentially temporary heightened sensitivity. Your brain, having flagged this item as something worth noting, begins diverting attentional resources toward detecting it in incoming information.
The item was present in your environment before you learned it. You simply were not detecting it. Now you are. This creates the subjective experience of the thing appearing "everywhere," when the accurate description is: the thing is appearing in awareness where before it was filtered out.
Psychologists measure selective attention using tasks like the dichotic listening paradigm, in which participants wear headphones and hear different messages in each ear, attending to one while shadowing (repeating aloud) the other. Classic research by Donald Broadbent and later Anne Treisman in the 1950s-60s established that unattended channels are not simply ignored — they can break through to awareness when they contain high-priority content (such as the listener's own name), demonstrating that the filter is responsive to relevance rather than purely mechanical. The Baader-Meinhof phenomenon is essentially the same mechanism applied to content that has recently been flagged as relevant through learning.
Confirmation Bias
Selective attention alone creates the increased detections. Confirmation bias creates the false interpretation of those detections.
Confirmation bias is the well-documented tendency to seek out, notice, and weight information that is consistent with existing beliefs, while unconsciously discounting information that contradicts them. Once the Baader-Meinhof phenomenon has generated several new detections of the newly noticed item, confirmation bias leads us to interpret those detections as evidence that the item really has become more common -- that our experience of increased frequency reflects reality rather than a change in our own perception.
The result is the full subjective experience: not just that you notice the thing more, but that you feel genuinely surprised by how often it is appearing, as if something has changed in the world rather than in your attention.
Peter Wason's classic 2-4-6 task (1960) provided one of the earliest experimental demonstrations of confirmation bias. Participants had to discover a rule governing number sequences by testing triplets. Most tested only confirming instances (numbers fitting their hypothesized rule) rather than disconfirming ones, leading them to false confidence. The same asymmetry operates in the Baader-Meinhof phenomenon: we notice and remember the confirmations (more appearances of the newly learned item) but not the absences.
"The frequency illusion is a beautiful example of how the brain's filtering system, which serves us extraordinarily well in most contexts, can create experiences that are profoundly misleading about what is actually changing: the world, or our attention to it."
The Neuroscience: Selective Attention and the RAS
The neurological basis of the Baader-Meinhof phenomenon involves the reticular activating system (RAS), a network of neurons in the brainstem that regulates alertness, attention, and arousal.
The RAS functions as a gateway between sensory input and conscious awareness. It continuously modulates what gets amplified into conscious processing and what gets suppressed. When you are highly attentive to a conversation, the RAS helps suppress the background noise of the restaurant you are sitting in. When you are expecting a specific sound (your name, your phone notification), the RAS increases sensitivity to that pattern in incoming auditory information.
Learning something new activates attention-related circuits that interface with the RAS, temporarily increasing its sensitivity to that stimulus pattern. This is why the effect tends to be most pronounced in the days and weeks immediately after learning something, and typically fades as the novelty diminishes and the item stops being treated as new information.
The related concept of priming is also relevant. Cognitive priming is the phenomenon where exposure to one stimulus increases the ease of processing related stimuli. If you have just been reading about technology companies, you are more likely to notice technology-related content in your subsequent information environment -- the priming has increased the accessibility of those concepts in your cognitive processing.
The Role of the Hippocampus and Novelty Detection
Neuroscience research has identified the hippocampus as playing a critical role in novelty detection and the encoding of new information. Functional neuroimaging studies have found that the hippocampus responds specifically to novel stimuli — and that this novelty response is accompanied by enhanced encoding, meaning new information is tagged more vividly in memory than familiar information.
Research by Bunzeck and Duzel (2006) published in Neuron demonstrated that the hippocampus and midbrain showed heightened activation in response to novel stimuli, and that this activation was accompanied by dopamine release in reward-related circuits. The dopaminergic response to novelty may be the neurochemical mechanism that flags newly learned items for elevated processing — effectively setting the attentional filter described by the Baader-Meinhof phenomenon at the neurochemical level.
This means the frequency illusion has a genuine biological basis in novelty-driven memory consolidation and attentional prioritization, not merely a vague tendency to notice things. The brain is literally dedicating more resources to recently acquired information.
Why the Illusion Feels Convincing
The Baader-Meinhof phenomenon is not easily dismissed once you are experiencing it, because it genuinely feels like objective observation rather than perceptual bias. Several factors make the illusion convincing:
We cannot observe our own attention filter: Because the filtering happens below conscious awareness, we have no direct access to how much of the environment we are actually not noticing. We experience only what reaches awareness, which gives us an incomplete and systematically biased sample of what is there.
We are better at noticing confirming instances than disconfirming ones: We notice the red cars that appear after buying our red car; we do not keep a running count of the days we went without seeing one. The asymmetric noticing creates asymmetric memory.
The coincidence is genuinely surprising in the short term: If you learn about an obscure fact and encounter it again two days later, that is a meaningful coincidence from a statistical standpoint in the short term -- even if the underlying cause is attention rather than objective frequency. The brain registers the co-occurrence as worthy of noting.
Social reinforcement: When you describe the experience to others, they often recognize it from their own lives, which reinforces the impression that the phenomenon is real rather than illusory.
The availability heuristic amplifies the effect: Daniel Kahneman and Amos Tversky's research on the availability heuristic (1973) showed that people judge the probability of events based on how easily examples come to mind. After encountering something several times in quick succession through the Baader-Meinhof mechanism, those examples are highly available in memory, leading the brain to judge the thing as genuinely common. The frequency illusion and the availability heuristic reinforce each other in a loop.
The Baader-Meinhof Phenomenon in Learning
Understanding the Baader-Meinhof phenomenon has practical applications for learning and knowledge acquisition.
New Vocabulary and Concepts
Language learners experience the Baader-Meinhof phenomenon constantly. A student learning Spanish who encounters a new word in their lesson will find it appearing in songs, conversations, and texts they encounter afterward. This is not coincidence; it is selective attention working in their favor. The word was present in the language environment before; now they have the encoding to detect it.
This observation has an optimistic implication: learning a concept or word opens access to the full existing stream of information about it. The environment is already dense with examples and applications; what learning provides is the filter that makes them visible.
Research by Nation (2001) on vocabulary acquisition in second language learning has documented how the number of exposures needed for robust word learning falls significantly when learners are actively looking for examples — essentially when the Baader-Meinhof mechanism is engaged. The phenomenon transforms passive learners into active detectors, dramatically increasing incidental learning opportunities.
Learning Accelerates on Its Own
A corollary is that learning tends to compound. Learning the vocabulary of a field does not just give you labels for new things -- it increases your ability to perceive and notice relevant information in the environment. An economist who learns about externalities begins noticing externalities in policy discussions, news stories, and everyday transactions that were always there but were invisible without the conceptual lens. The learning itself makes further learning more available.
This is one reason that broad, concept-level knowledge often has higher leverage than narrow factual knowledge: concepts act as attentional filters that continuously pull relevant instances out of the information environment.
Eleanor Rosch's research on conceptual categories and prototype theory in the 1970s demonstrated that categories are not neutral containers but active perceptual organizers. Once you have a robust conceptual category — a clear sense of what something is — you are better and faster at recognizing instances of it in the environment. Learning sharpens perception in a very literal sense.
Implications for Education
Teachers and curriculum designers can use the Baader-Meinhof mechanism intentionally. Introducing a concept and then creating opportunities for students to encounter it in multiple independent contexts amplifies the learning. The varied encounters are not simply repetition; they engage the selective attention mechanism in slightly different ways, reinforcing both the encoding and the pattern-detection ability.
Spaced repetition study methods work partly through this mechanism: by reactivating a concept at intervals, they maintain the selective attention filter active across a longer period, increasing the likelihood of encountering the concept in natural contexts and deepening the associative connections.
A study by Cepeda et al. (2006) in Psychological Science in the Public Interest reviewed the literature on spaced practice and found strong evidence that distributed practice substantially outperforms massed practice for long-term retention. The Baader-Meinhof mechanism is one component of why — spaced reactivation maintains the attention filter in an active state across the inter-session intervals, allowing incidental reinforcement through environmental encounters.
The Baader-Meinhof Phenomenon in Marketing
Marketers exploit the frequency illusion deliberately and systematically.
Retargeting Advertising
Retargeting is the practice of showing ads to users who have previously visited your website or interacted with your brand. When you visit a product page for a pair of running shoes and then see ads for that exact product on every website you subsequently visit, that is retargeting at work.
Retargeting is powerful partly because it exploits the Baader-Meinhof phenomenon. The initial website visit primes your attention for the brand. The subsequent ads are then noticed not only because of the targeting but because your selective attention has been activated. You also begin noticing the brand in organic contexts -- a friend mentioning it, seeing it on a store shelf, spotting the logo on a jogger's shirt -- in ways you would not have before the priming.
This creates the impression that the brand is ubiquitous, even if its actual market penetration is modest. The psychological effect of frequency is disproportionate to the actual frequency.
Research by Bart et al. (2014) found that retargeting ads performed substantially better when delivered shortly after the initial site visit — consistent with the Baader-Meinhof mechanism, which is most potent in the period immediately following initial exposure.
Brand Awareness Campaigns
Broad brand awareness advertising (billboards, TV spots, sponsorships) does not just create impressions in the moment of exposure. It primes audiences to notice the brand in subsequent contexts. A brand awareness campaign that generates initial exposure creates a Baader-Meinhof effect that extends the effective reach of the campaign beyond its measured impressions.
This is why brand awareness is difficult to measure precisely: the effect of exposure is not confined to the moment of the exposure but propagates forward through selective attention.
Byron Sharp's influential How Brands Grow (2010), drawing on the Ehrenberg-Bass Institute's research, argues that the primary mechanism of advertising effectiveness is mental availability — keeping a brand salient in memory so it comes to mind in purchase contexts. The Baader-Meinhof phenomenon is essentially a temporary, intense version of mental availability: the brand or product comes to mind with unusual frequency because it was recently encoded.
Product Launches and Buzz
When a new product launches with significant press coverage and social media discussion, early adopters begin noticing and discussing it, which generates more coverage, which activates the Baader-Meinhof phenomenon for more people, which generates still more discussion. The launch strategy is partly designed to create enough initial critical mass that the frequency illusion kicks in for a broad audience.
This is the mechanism behind "launch-phase" marketing investment — concentrating exposure rather than spreading it evenly over time, because concentrated exposure is more likely to activate the Baader-Meinhof threshold where perceived ubiquity kicks in.
The Phenomenon in Personal Life: Career, Relationships, and Identity
The Baader-Meinhof phenomenon operates in personal life in ways that extend beyond the simple noticing of words or brands.
Career Decisions and Industry Awareness
When you begin considering a new career path, industry, or skill set, the Baader-Meinhof phenomenon activates a powerful detection system. Articles, conversations, and opportunities that were always present in your information environment begin surfacing with apparent regularity. This is not the universe aligning with your intention — it is your newly activated attentional filter doing its job.
This has practical implications: the act of deciding to explore something tends to generate an evidence base for pursuing it, because the frequency illusion makes examples of people doing that thing, resources about it, and opportunities related to it suddenly visible. This can be deeply useful — treating the Baader-Meinhof effect as a tool for discovery rather than as a misleading coincidence.
Relationship Patterns
People who have recently experienced a relationship ending often report noticing couples everywhere. Those who have just had a baby notice babies everywhere. Those confronting a health scare notice references to their condition everywhere. In each case, the phenomenon can feel overwhelming — as if the world is rubbing in what is most painful or salient.
Understanding the mechanism does not eliminate the emotional weight but provides a context that can reduce the sensation of the world being organized around one's personal situation — a cognitive shift that can be genuinely useful in difficult periods.
Identity Formation
Identity development, particularly in adolescence and young adulthood, is substantially shaped by the Baader-Meinhof phenomenon. When a young person begins exploring a possible identity — a political philosophy, a subculture, a set of values — the frequency illusion makes examples of that identity visible everywhere, reinforcing the sense that it is a real and robust option. The environment appears to confirm the emerging identity, partly because the attention filter is now scanning for confirmation.
This is not purely deceptive — the Baader-Meinhof mechanism is genuinely exposing information that was always present but invisible. But it means that identity exploration should be understood as a process that actively constructs the apparent evidence base for the identities being explored.
Distinguishing Real Patterns from Frequency Illusion
A practical challenge the Baader-Meinhof phenomenon poses is distinguishing genuine changes in the world from changes in your own attention. Sometimes things really do become more common; sometimes you are just noticing existing things more. The tools for distinguishing these cases:
| Approach | How It Helps |
|---|---|
| Check base rates | Has this thing actually become statistically more frequent? Data sources, trend analyses |
| Consider recency | Did you recently encounter this thing for the first time? If yes, frequency illusion is likely |
| Look for negative instances | Are you also noticing the times the thing does not appear? Or only when it does? |
| Ask others | Have others noticed the increase independently, or only you? |
| Check timing | Did frequency seem to increase right after your first exposure, or gradually over time? |
| Consult objective data | News archives, Google Trends, publication databases can help distinguish real trends |
| Watch for fading | Does the apparent frequency reduce after the initial burst? Frequency illusion typically fades |
The Baader-Meinhof phenomenon tends to peak shortly after the initial exposure and fade as novelty decreases. Real increases in frequency do not typically behave this way.
Google Trends is a particularly useful tool for this check — it allows direct comparison of actual search frequency over time against one's subjective sense of a term's recent ubiquity. Many apparent Baader-Meinhof experiences are confirmed as frequency illusions by showing no actual trend change in objective data.
Related Phenomena
The Baader-Meinhof phenomenon sits in a family of related cognitive experiences:
The mere exposure effect: The tendency to develop preference for things simply because they have become familiar. Repeated noticing through the frequency illusion can trigger the mere exposure effect, generating mild positive associations with something encountered frequently. Robert Zajonc's (1968) foundational work on the mere exposure effect demonstrated that repeated exposure to stimuli — even subliminal exposure — increases liking. The Baader-Meinhof mechanism, by increasing encountered frequency of recently learned items, inadvertently generates mere exposure effects that may make those items more positively evaluated.
The clustering illusion: The tendency to see patterns in random data. When the Baader-Meinhof phenomenon produces a cluster of encounters with something in a short period, the clustering illusion can lead people to interpret this as meaningful rather than as expected variance.
Synchronicity: Carl Jung's concept of meaningful coincidence. The Baader-Meinhof phenomenon explains many of the experiences that people describe as synchronicity -- apparent coincidences that feel too meaningful to be random. They feel meaningful not because they are statistically extraordinary but because selective attention has made them salient.
Priming effects broadly: A range of cognitive science research shows that prior exposure to a concept influences subsequent perception, interpretation, and behavior in ways that operate outside conscious awareness. John Bargh's work on priming and automaticity established that many of these influence effects operate entirely below the threshold of conscious awareness. The Baader-Meinhof phenomenon is one of the most vivid and personally noticed manifestations of priming.
The Texas sharpshooter fallacy: The logical error of identifying patterns after the fact from data with inherent variance. The Baader-Meinhof phenomenon is a specific instance of this: the "pattern" of increased frequency is identified from the subset of data that selective attention has made available, not from the full data set.
What the Baader-Meinhof Phenomenon Reveals About the Mind
The Baader-Meinhof phenomenon is a striking illustration of several things that are generally true about human cognition:
What we experience as "the world" is heavily filtered: Consciousness is not a transparent window onto reality; it is a highly selective, heavily processed reconstruction based on what the brain has decided to make available to awareness. The gap between what is out there and what reaches awareness is enormous.
We cannot observe our own attention from the inside: The filtering itself is invisible. We experience only the filtered output, which means we have no direct access to what we are not noticing, which means our sense of how representative our observations are is systematically overconfident.
Learning changes perception, not just knowledge: Acquiring a concept does not only add information to a store; it changes the perceptual system so that information related to the concept becomes more visible in experience. This is one of the most useful properties of learning.
The world is richer than we perceive at any moment: This is perhaps the most reassuring implication. The richness and complexity of the world always exceeds what any single attentional configuration can pick up. The Baader-Meinhof phenomenon offers a small experiential demonstration of this: every time you learn something new and then notice it everywhere, you are experiencing the gap between the world's density and the narrowness of any single moment's attention.
Cognitive biases are not failures of intelligence: The mechanisms underlying the Baader-Meinhof phenomenon — selective attention, novelty detection, confirmation bias — are generally adaptive. The same attentional filter that creates the frequency illusion is essential for functioning in a world of overwhelming sensory input. The bias is a side effect of machinery that is mostly working correctly.
The Metacognitive Opportunity
Psychologist Keith Stanovich at the University of Toronto has written extensively on dysrationalia — the ability to think rationally being distinct from general intelligence. His work suggests that people can be highly intelligent while remaining systematically susceptible to cognitive biases, and that reducing bias requires not just cognitive ability but metacognitive skill — the ability to think about one's own thinking.
The Baader-Meinhof phenomenon, because it is unusually vivid and personally noticeable, offers one of the best opportunities for developing metacognitive awareness of one's own attentional biases. When you catch yourself thinking "I keep seeing this everywhere," and correctly identify it as a frequency illusion rather than a real pattern, you are exercising exactly the kind of metacognitive checking that Stanovich identifies as a key component of rational thinking.
Conclusion
The Baader-Meinhof phenomenon is not magic, not coincidence, and not the universe sending messages. It is selective attention doing what it does extraordinarily well: flagging recently relevant information for elevated monitoring, making the newly known visible in a world that was always full of it.
The name is improbably memorable for something so cognitively fundamental -- which is fitting. The Baader-Meinhof phenomenon is the kind of concept that, once you learn it, you will notice illustrated around you constantly. That experience of seeing it everywhere after first encountering it is itself the phenomenon in action.
Understanding it serves two purposes. Practically, it helps distinguish genuine changes in the world from changes in your attention — a skill of increasing value in an information environment designed to manufacture the impression of trends and urgency. And philosophically, it is a reminder that the world you experience is a construction -- a highly useful, generally reliable, but always partial and filtered representation of a reality far richer than what reaches awareness at any given moment.
The things you are not noticing right now are beyond counting. The Baader-Meinhof phenomenon gives you a small, regular glimpse of that infinity — every time you learn something new.
References
- Zwicky, A. (2006). The frequency illusion. Language Log. Stanford University.
- Broadbent, D. E. (1958). Perception and Communication. Pergamon Press.
- Treisman, A. M. (1964). Selective attention in man. British Medical Bulletin, 20(1), 12-16.
- Wason, P. C. (1960). On the failure to eliminate hypotheses in a conceptual task. Quarterly Journal of Experimental Psychology, 12(3), 129-140.
- Tversky, A., & Kahneman, D. (1973). Availability: A heuristic for judging frequency and probability. Cognitive Psychology, 5(2), 207-232.
- Bunzeck, N., & Duzel, E. (2006). Absolute coding of stimulus novelty in the human substantia nigra/VTA. Neuron, 51(3), 369-379.
- Kahneman, D. (2011). Thinking, Fast and Slow. Farrar, Straus and Giroux.
- Nation, I. S. P. (2001). Learning Vocabulary in Another Language. Cambridge University Press.
- Cepeda, N. J., Pashler, H., Vul, E., Wixted, J. T., & Rohrer, D. (2006). Distributed practice in verbal recall tasks: A review and quantitative synthesis. Psychological Bulletin, 132(3), 354-380.
- Sharp, B. (2010). How Brands Grow: What Marketers Don't Know. Oxford University Press.
- Zajonc, R. B. (1968). Attitudinal effects of mere exposure. Journal of Personality and Social Psychology Monograph Supplement, 9(2, Pt. 2), 1-27.
- Bargh, J. A., Chen, M., & Burrows, L. (1996). Automaticity of social behavior: Direct effects of trait construct and stereotype activation on action. Journal of Personality and Social Psychology, 71(2), 230-244.
- Stanovich, K. E. (2009). What Intelligence Tests Miss: The Psychology of Rational Thought. Yale University Press.
Frequently Asked Questions
What is the Baader-Meinhof phenomenon?
The Baader-Meinhof phenomenon (also called the frequency illusion) is the cognitive experience where something you recently learned about or noticed suddenly seems to appear everywhere. The name comes from a 1994 online discussion where a person noticed the name of the German terrorist group Baader-Meinhof twice in a short period after first encountering it. The phenomenon is not a coincidence but a result of selective attention: your brain, having flagged the new item as relevant, now notices it in contexts where it previously passed unobserved.
What causes the Baader-Meinhof phenomenon?
Two cognitive mechanisms work together to produce the Baader-Meinhof phenomenon. First, selective attention: once your brain flags something as significant, it diverts attentional resources toward detecting that thing in incoming sensory information. It was always present; you were not filtering for it before. Second, confirmation bias: once you have noticed the thing a few times, you take those instances as evidence that it is truly more common, rather than recognizing that you are simply noticing it more. Together, selective attention creates the increased detections and confirmation bias makes those detections feel meaningful.
Is the Baader-Meinhof phenomenon related to the reticular activating system?
Yes. The reticular activating system (RAS) is a network of neurons in the brainstem that filters incoming sensory information and determines what reaches conscious awareness. The RAS is closely linked to attention and arousal -- it is one of the mechanisms by which your brain prioritizes what to pay attention to out of the enormous flood of incoming sensory data. When you learn something new or mark it as relevant, the RAS is thought to increase sensitivity to that stimulus, explaining why you begin noticing it in environments where you previously did not.
How is the Baader-Meinhof phenomenon used in marketing?
Marketers use the frequency illusion deliberately through retargeting advertising. When you visit a website and then see ads for that company everywhere across other websites and social media, that is not coincidence -- it is deliberate ad targeting using cookies and pixel tracking. But the Baader-Meinhof phenomenon amplifies the effect: because you are now primed to notice the brand, you register its presence in organic contexts (a friend mentioning it, seeing it on a shelf) more than you would have before. This makes brand awareness campaigns feel more pervasive than their actual reach warrants.
What is the difference between the Baader-Meinhof phenomenon and confirmation bias?
They are related but distinct. The Baader-Meinhof phenomenon (frequency illusion) is specifically about noticing something more frequently after first learning about it -- a shift in selective attention. Confirmation bias is the broader tendency to seek out and weight information that confirms existing beliefs while discounting contradicting information. In the Baader-Meinhof phenomenon, confirmation bias plays a secondary role: after selective attention creates more detections, confirmation bias reinforces the false conclusion that the thing has genuinely become more common.