Quick Answer: The Hot Hand Fallacy is the belief that a person who has experienced success has a greater chance of further success in additional attempts. For decades, statisticians proved this was a cognitive illusion caused by humans seeing patterns in random data. However, recent studies suggest there might actually be a tiny, measurable "hot hand" effect in certain skill-based activities like basketball.
The Origin of the Fallacy
In a famous 1985 paper, researchers analyzed the shooting records of the Philadelphia 76ers. Basketball players perfectly believed that if they made several shots in a row, their next shot was more likely to go in. However, the data showed the opposite: the probability of making a shot after a hit was statistically identical to (or slightly lower than) the probability after a miss. The sequence of hits and misses was essentially a random coin flip weighted by the player's average skill.
Why Our Brains See Streaks
True randomness produces "clumps." If you flip a coin 100 times, you are highly likely to see a streak of 6 heads in a row. Human brains are terrible at recognizing true randomness; we assume alternating sequences (H, T, H, T) are random, but view streaks (H, H, H, H, H) as meaningful patterns. So when a player hits 5 shots in a row, we attribute it to being "hot" rather than normal statistical variance.
The Plot Twist: The Fallacy Fallacy
In 2015, economists revisited the 1985 data using new statistical methods. They found a subtle mathematical flaw in how the original test measured streaks in finite sample sizes. Correcting for this "selection bias," they discovered a slight but real positive effect: a player who makes a shot is actually slightly more likely (about 1-2%) to make the next one. While the massive psychological "hot streak" is largely an illusion, a small momentum effect can exist in human skill execution.