What is The Hot Hand
Fallacy?
Definition
The Hot Hand Fallacy, also known as streak shooting, is the belief that the probability of a made shot is greater following a previously made shot rather than a miss. [1]
Irrational Belief
This belief is of course irrational. All statistical analysis collected on the subject, first conducted by Thomas Gilovich, show that the outcome of a shot has no positive correlation with the outcome of the previous shots taken. [2]
Irrational Belief that is Predictable, Pervasive, and Powerful
When asked if a player “has a better chance of making a shot
after having just made his last two or three shots than he does after having
just missed his last two or three shots,” 91% of fans surveyed responded “Yes.”[3]
When surveyed professional players and coaches like basketball fans alike show equal levels
of belief in the hot hand fallacy.[4]
Moreover, these results are pervasive even when shown the data proving otherwise. When the results of Gilovich’s first studies where published the
overwhelming public response was of disbelief.[5] Most famously famed Boston Celtics'
Coach Red Auberbach's response to the study was, “Who is this guy? So he makes a
study. I couldn’t care less.”[6]
Irrational Belief That Cannot Be Explained By Lack of Proper Incentives
One may argue that the average fan may not have the proper incentives to correct for this fallacy. After-all, the root of irrational beliefs caused by biases and heuristics is commonly (but misleadingly) believed to be a “lazy and inattentive minds.”[7] This explanation should be resisted in light of the evidence that even trained professionals are prone to the streak shooting belief. Conceivably, in the context of the multi-billion dollar NBA industry there are strong incentives to pay attention and devote full cognitive resources to understanding the phenomenon of “streak shooting.” Failure to be understand streak shooting can be costly! As Gilovich explains,
“Passing the ball to the player who is ‘hot’ is a common strategy endorsed by basketball players. It is also anticipated by the opposing team who can concentrate on guarding the ‘hot’ player. If another player, who is less ‘hot’ on that particular day, is equally skilled, then the less guarded player would have a better chance of scoring. Thus the belief in the ‘hot hand’ is not just erroneous, it could be costly.” [8]
The occurrence of even well incentivized people still
falling prey to this fallacy is not a surprise. As researchers Camerer and
Hogarth have found, “no replicated study has made rationality violations
disappear purely by raising incentives.”[9]
Why Does the Erroneous Belief of Streak Shooting Exist?
We Are Associative Machines Built To See Patterns Where
None Exist
The hot hand fallacy is caused by the representatitiveness
bias.[10]
We have a positive association bias in which the likelihood of a made shot is incorrectly
perceived to be greater following a made basket.[11]
This occurs because we are built to see patterns where none exist. When we see
two shots being hit, we assume the successive shots thereafter similarly will
go in. In other words, we judge the likelihood of successive shots based on the
representatitiveness of the outcomes of the most recent shot attempts. The
association of the recently made or missed basket is still so fresh in our
head!
We Lack the Ability to Intuitively Grasp Random Sequences
Moreover, the associative machine seeks to explain
perceived abnormalities of random sequence.[12]
This is because we lack the ability to intuitively grasp random sequences. [13]
A random sequence is a sequence of events in which the outcome of each individual
event cannot be predicted with certainty. Basketball shots are indeed random
sequences similar to coin tosses.[14]
The comparison seems intuitively unreasonable because the chance of a shot is
dependent on other parameters which may not be the same in every instance, such as defensive intensity, player skill, and
shot selection.[15]
Nevertheless, the probability of each individual shot is largely independent on
the outcome of the previous shots taken.[16]
Similarly with coin tosses, although the
probability of getting heads when you flip a coin is dependent on other
parameters such as “the initial position of the coin, and it’s angular and
vertical momentum,” it is nevertheless independent on the outcome of the
previous flips taken.[17]
Like a random sequence of shots resulting in 3 baskets made
in a row, it is not inconceivable (and in fact quite probable) to have a random
sequence of coin flips come up heads 3 times in a row. However, our associative
machine upon viewing such a pattern inaccurately seeks to make use of this
seemingly logical pattern within the random sequence, leading us to a mistaken perception on how random sequences work.
Findings Do Not Make Basketball a Game of Chance, and Not Skill
Of course, these findings do not make basketball a game
of chance as oskill.[18]
It merely means that the likelihood of a make on successive shots is
independent of the outcomes of the previous shots taken.[19]
Strategy, skill, and other variables still play a part in deciding which shots
to take and the likelihood you are to make it.[20]
Conclusion
The hot hand fallacy is just one of many ways in which a better
understanding of behavioral science can help us. Failure to be aware of this heuristic based misperception of streak shooting can be costly. Nevertheless people, even in positions of
great incentive, fail to consciously adjust their intuitive assessments in light
of the research. In other words their system 2 (conscious thought) refuses to
reassess the faulty information provided to them by their system 1 (subconscious
thought, also known as intuition). They consciously reject the teachings of behavioral
science in favor for beliefs that reconcile with our desire to see patterns, leading
to incorrectly believing in the phenomenon of streak shooting. Therefore there
is arbitrage to be had by those who do accept the teachings of behavioral science.
In a world where every advantage helps, perhaps refusing to adopt strategies
based on irrational beliefs can provide the necessary winning edge.
[1]
Thomas Gilovich, Robert Vallone & Amos Tversky, The Hot Hand in Basketball: On the
Misperception of Random Sequence, 295-314. 296 (1985).
[2] Id.at 295. In relevant part: “detailed analyses of the shooting records of
the Philadelphia 76ers provided no evidence for a positive correlation between
the outcomes of successive shots. The same conclusions emerged from free-throw
records of the Boston Celtics, and from a controlled shooting experiment with
the men and women of Cornell’s varsity teams. The outcomes of previous shots
influenced Cornell players’ predictions but not their performance.” The
different tests where done to control for and eliminate the various factors
surrounding a shot such as skill, defensive intensity, and shot selection.
[3] Id. at 297.
[4] Id. at 310. In relevant part:
“[Discussing surveyed 76ers players] Most
of the players (six out of eight) reported that they have on occasion felt that
after having made a few shots in a row they ‘know’ they are going to make their
next shot-that they ‘almost can’t miss’… All of the players believed that it is
important ‘for the players on a team to pass the ball to someone who has just
made several (two, three, or four) shots in a row.’ Five players and the coach
also made numerical estimates. Five of these six respondents estimated their
field goal percentage for shots taken after a hit (mean: 62.5%) to be higher
than their percentage for shots taken after a miss (mean: 49.5%).”
[5]
Daniel Kahneman, Thinking Fast and Slow, 172.
[6] Id.
[7]
Thomas Gilovich, Dale Griffin, & Daniel Kahneman, Heuristics And Biases, 1-20, 2
(2002), The Psychology of Intuitive Judgment. In relevant part: “Automatic or Deliberate? There is another
dichotomous aspect of the heuristics and biases approach that warrants
discussion. Heuristics have often been described as something akin to
strategies that people use deliberately in order to simplify judgmental tasks
that would otherwise be too difficult for the typical human mind to solve. This
use of the term fits with the ‘cognitive miser’ metaphor that proved popular in
the field of social cognition (Fiske & Taylor, 1991). The metaphor suggests,
perhaps unfortunately and unwisely, that the biases documented in the
heuristics and biases tradition are the product of lazy and inattentive minds.
The implication is unfortunate and potentially misleading because the biases
identified in this tradition have not been appreciably reduced by incentives
for participants to sit straight, pay attention, and devote their full
cognitive resources to the task. After reviewing 74 studies, Camerer and
Hogarth (1999) concluded that incentives can reduce self-presentation effects,
increase attention and effort, and reduce thoughtless responding, but noted
that ‘no replicated study has made rationality violations disappear purely by
raising incentives.’”
[8]
See Gilovich Hot Hand, supra note 1,
at 313.
[9]
See Gilovich Heuristics & Biases,
supra note 7.
[10] See
Gilovich Hot Hand, supra note 1, at 296.
[11] Id. at 296
[12]
See Kahneman, supra note 5,
at 169.
[13]
See Gilovich Hot Hand¸supra note 1,
at 311. In pertinent part: “We attribute
this phenomenom to a general misconception of the laws of chance associated
with the belief that small as well as large sequences are representative of
their generating process. This belief induces the expectation that random
sequences should be far more balanced than they are, and the erroneous
perception of a positive correlation between successive shots.”
[14] Id. at 297. In relevant part: “It may seem unreasonable to compare
basketball shooting to coin tossing because a player’s chances of hitting a
basket are not the same on every shot. Lay-ups are easier than 3-point field
goals and slam dunks have a higher hit rate than turnaround jumpers.
Nevertheless, the simple binomial model is equivalent to a more complicated
process with the following characteristics: Each player has an ensemble of
shots that vary in difficulty
(depending, for example, on the distance from the basket and on defensive
pressure), and each shot is randomly selected from this ensemble. This process
provides a more compelling account of the performance of a basketball player,
although it produces a shooting record that is indistinguishable from that
produced by a simple binomial model in which the probability of a hit is the
same on every trial.”
[15] Id.
[16] Id.
[17] Id. 312-313.
[18] Id. at 312.
[19] Id.
[20] Id.
No comments:
Post a Comment