The Base Rate Fallacy
Vivid case-specific evidence can overshadow how common an event is overall.
The Mechanism: The base-rate fallacy occurs when people underweight the general frequency of an event while focusing on specific evidence. Bayesian reasoning combines prior probability with how strongly new evidence supports a hypothesis.
The Philosophical Pivot: A vivid story can feel more informative than a population rate, even when it is less diagnostic. The mind is drawn to the particular because particular people and events are easier to imagine.
The Horizon: Medical tests, risk scores, and news reports can mislead when prevalence is omitted. Communicating absolute frequencies and uncertainty can help people understand what evidence actually means.
Base rates are not a substitute for individual evidence; they provide context for interpreting it. Both the general pattern and the specific person matter.
A detail can be true and still be less informative than the background it interrupts.
A vivid fact is not automatically a likely explanation.
What is the underlying frequency of the event I am worried about, and how diagnostic is the detail that caught my attention?