Happy sunday everyone! We had a gorgeously warm day in chi-town today. If you were in town, i hope you had a chance to enjoy some outdoor time. If you follow basketball, the semi-finals started today with Washington Wizards vs. Atlanta Hawks, and Memphis Grizzlies vs. Golden State Warriors. Making use of my cable subscription, which I will be canceling once NBA season is over, we watched the Grizzlies vs. Warriors game. The final score was GRIZZLIES 86 – 101 WARRIORS.
If you’re not into basketball, I hope I haven’t lost you yet. What about some Psychology?
I want to talk about a phenomenon called “hot hands” where players are thought to have a better chance of making a basket if they’ve made their past few shots in a row. Some people might call it a streak, unstoppable, on fire, etc. One basketball player said “It’s like the automatic, unconscious feeling. If I hit two in a row, I bet the third one almost always goes in.”


Is it true? Research have found that it is not. The probability of a player making a shot is independent of whether he or she has made the shot previously (1).  The Hot Hand Fallacy was first discovered by 3 Psychologists: Amos Tversky, Thomas Gilovich, and Robert Vollone. They found that people have difficulty understanding true randomness in situations, meaning that we find patterns in things that are not random. For example, a random Heads/Tails sequence could be HHHHHHTTTTTT or HTTTHTTHHHTH, but people tend to think that the second one is more random than the first one when it is not. Similarly, the hot hand fallacy makes basketball players or their viewers think that their chance of making a basket is linked to other shots more than they should.

This fallacy is not limited to basketball, though the term originated from it. It also applies to gambling e.g. on a roulette wheel – when the ball lands on black the past 5 rounds, are you going to bet on red now? What other examples can you think of?
It is important to be aware when you’re perceiving patterns in a non-random setting. Think about whether your psychology or emotion is driving the thought. Does it contradict statistics?


(1) Gilovich, Thomas; Tversky, A. & Vallone, R. (1985). “The Hot Hand in Basketball: On the Misperception of Random Sequences”. Cognitive psychology 3 (17): 295–314.
The original research studied Philadelphia’s 76-ers because they were the only team at the time that kept records of their shots. However, NBA statistics have now evolved a long way and there are many more data points to evaluate whether hot hand fallacy is truly a fallacy. Although some research have found ways to disprove the fallacy, it is still difficult to find strong statistical evidence that “hot hand” exists.
As I type, the chi-sky just turned from dark and stormy – did I just jinx it?

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