Concept · Cognitive Bias: Decision-making and judgment biases
Availability heuristic
Origin: Tversky & Kahneman, 1973
The Biological Bridge
This business construct is human-invented, but the outcome it's trying to achieve has deep biological roots.
Surface Construct
Judging probability by ease of recall
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Underlying Outcome
Use memory accessibility as a proxy for frequency/importance
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Biological Mechanism
Recency-weighted learning. In stable environments, recent events ARE more predictive than distant ones. A predator attack yesterday is more relevant than one five years ago because it indicates current predator presence. The brain encodes recent/vivid events more strongly because they're typically more actionable.
Key Insight: Availability heuristic fails when media exposure decouples vividness from actual frequency. It works when your sample is representative of your actual environment.
The Full Picture
Animals overestimate predation risk after witnessing an attack—the vivid memory dominates risk assessment regardless of actual predator density. Deer avoid areas where they've seen wolves even when wolves have moved on, because availability (mental accessibility) trumps base rates. This isn't irrationality; it's efficient processing under uncertainty. Building accurate probability models requires extensive data, but survival requires immediate decisions. Evolution favors organisms that use available information quickly over those that wait for statistical significance.