Why can a memorable event seem more common than it is?

It is often useful to remember examples when estimating how common something is. Frequent experiences may be easier to recall. But ease of recall can also change for reasons other than frequency.

An unusual, vivid event may be discussed repeatedly and remain easy to imagine. Quiet ordinary events may receive little attention. A person can then remember the unusual event first even when the full record contains many more ordinary ones.

Psychologists call judging frequency or likelihood through the ease of bringing examples to mind the availability heuristic. It can be efficient, but vividness, recency and repeated exposure can shift the judgment away from the actual counts.

The distinction is between accessible memories and a representative record. Neither one striking example nor a feeling of familiarity supplies the missing denominator. Knowing how many opportunities there were helps turn a remembered event into a more informative comparison.