Plain-language answer
People routinely estimate how common or likely something is by how easily examples of it come to mind — a mental shortcut called the availability heuristic. Anything that makes an example easier to recall (it happened recently, it was emotionally striking, it was widely reported) makes that category feel more frequent, whether or not it actually is.(Tversky & Kahneman, 1973) Coincidences are, almost by definition, unusually memorable — which means availability quietly inflates how common they feel every time one is recalled.
Why it matters
“Coincidences like this happen to me all the time” is a claim about frequency built entirely on memory, and memory is not a neutral record — it is a search process biased toward whatever is easiest to retrieve. A striking coincidence gets rehearsed, retold, and re-encoded every time it is recalled or shared, making it progressively easier to bring to mind, while the vastly larger number of ordinary, unremarkable days that produced no notable coincidence leave no comparable trace to compete with it in memory. The result is a systematically distorted sense of how often coincidences actually occur.
Worked example: fluency as evidence
In classic demonstrations of the availability heuristic, people asked whether more English words start with the letter K or have K as their third letter reliably (and incorrectly) say “starts with K” — because words are mentally organized and searched by their first letter, making first-letter-K words far easier to retrieve, even though third-letter-K words are actually more common.(Tversky & Kahneman, 1973) The mechanism generalizes directly: ease of retrieval gets mistaken for a signal about real-world frequency, in contexts as different as vocabulary and life events.
Applied to coincidences: the three or four spectacular pattern-matches a person remembers vividly across a lifetime feel numerous and significant precisely because they are so retrievable, while the tens of thousands of uneventful days that never produced anything worth remembering are, by definition, not competing for attention in memory. Comparing “vivid memorable events” against “an unrepresented baseline of ordinary days” is not comparing like with like.
Common misconception
“I can think of so many examples, so this must happen often” treats ease of recall as if it were a direct, unbiased measurement of frequency. It measures something real — memorability — but memorability is driven by vividness, emotional intensity, recency, and repetition of retelling, none of which track actual frequency reliably.
Limits and open questions
The availability heuristic explains a systematic direction of bias (memorable things feel more common) without providing a way to correct for its exact size in any one person’s case, because there is no independent record of every day that produced no memorable coincidence to compare against. The practical response is not to distrust memory entirely, but to treat “I remember several examples” as weak evidence of frequency on its own, and to look for an independent count or base rate wherever one is available.
Related
- Pattern perception and the clustering illusion covers a related distortion — noticing structure in genuinely random sequences — that often works together with availability to make a coincidence feel both frequent and meaningful.
- Hindsight bias covers a related memory distortion specific to how outcomes get reconstructed as having been predictable.
Key takeaways
- People judge frequency by how easily examples come to mind, not by an accurate internal tally — a shortcut called the availability heuristic.
- Coincidences are inherently more memorable than ordinary days, which systematically inflates how frequent they feel in retrospect.
- “I can think of many examples” is weak evidence of true frequency on its own, because the un-memorable non-examples are never competing for attention in the comparison.