## When Vivid Memories Distort Probability
The availability heuristic is the tendency to estimate the probability of an event based on how easily examples come to mind. Events that are vivid, recent, or emotionally charged are mentally "available" and therefore perceived as more probable than they actually are.
## Betting Examples
**The memorable upset:**
Brazil lost 7-1 to Germany in the 2014 World Cup. This vivid, shocking result is mentally available to everyone who saw it. Bettors who experienced this event may systematically overestimate the probability of historic upsets when Brazil plays strong opposition — even 10 years later.
**The spectacular goal:**
A striker scores a spectacular 35-yard volley in a broadcast match. This goal is memorable and mentally available. His anytime scorer price is affected by public memory of spectacular goals disproportionately to his underlying xG rate.
**The dramatic late goal:**
You personally watched a match where a 94th-minute goal overturned a winning position. This experience makes late goals feel more probable in future matches you watch than the statistical base rate warrants.
## Why Availability Distorts Markets
Public betting markets are influenced by what bettors think about — not just what the statistics show. The availability heuristic systematically inflates prices on memorable outcomes (high-profile upsets, famous strikers, dramatic comebacks) and deflates prices on statistically probable but unremarkable outcomes (the quiet 2-0 win by the deserving favourite).
## The Systematic Correction
Keep a probability calibration log: for each category of bet (e.g. "favourite wins by 2+ goals"), track your estimated probability vs actual frequency. If your estimated frequency is consistently above actual frequency for a category that includes vivid counterexamples, availability bias is likely at work.
The correction is mechanical: return to base rates and model outputs. The vivid exceptions are exceptions — their vivid quality does not make them typical.
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