Availability Heuristic

We judge event likelihood by how easily examples come to mind via the availability heuristic—not by actual statistical frequency—and this bias skews risk perception more than any other on this list. For example, shark attacks kill roughly 5 people annually worldwide, while car accidents claim 40,000 in the US alone, yet many fear sharks more due to vivid media coverage. This triggers 20% fewer flights after a plane crash dominates headlines, despite flying being 95 times safer than driving per mile. Introduced by Kahneman and Tversky in 1973, this heuristic outperforms #1's Confirmation Bias by shaping immediate, visceral reactions before logic or belief can intervene. The antidote is rigorous data-checking against base rates—especially when emotional examples dominate your mental database.