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[Plutarch] "It is no great wonder if in
the long process of time, while fortune takes her course, hither
and thither... numerous coincidences should spontaneously occur". |
Avoid
the pits by following the pendulum, Niederhoffer and Kenner,
2002
 NBA
teams ride the shooter with the hot hand, and baseball players live
and die with hitting streaks. But are these examples of hot hands
real, or do they just seem that way because of the vagaries of memory?
Most researchers who have studied hot hands conclude the concept
is a myth. The expert in this field, Cornell University psychology
professor Gilovich,
concluded that "detailed analyses provided no evidence for
a positive correlation between the outcomes of successive shots".
An excellent book that reports tests for streakiness of batters
and teams in baseball is "Curve
Ball" by Jim Albert and Jay Bennett. They found that in
one year, only six of 30 teams showed streakiness, a result consistent
with chance.
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The
Hot Hand in Basketball: Fallacy or Adaptive Thinking?, Burns
In basketball, players believe that they should "feed the hot
hand", by giving the ball to a player more often if that player
has hit a number of shots in a row. However, Gilovich, Vallone &
Tversky (1985) analyzed basketball players' successive shots and
showed that they are independent events. Thus the hot hand seems
to be a fallacy. Taking the correctness of their result as a starting
point, I suggest that if one looks at the hot hand phenomena from
Gigerenzer & Todd's (1999) adaptive thinking point of view,
then the relevant question to ask is does belief in the hot hand
lead to more scoring by a basketball team? By simulation I show
that the answer to this question is yes, essentially because streaks
are predictive of a player's shooting percentage. Thus belief in
the hot hand may be an effective, fast and frugal heuristic for
deciding how to allocate shots between member of a team. |
When
it is adaptive to follow streaks: Variability and stocks, Burns,
2003
"Streaks of events are ubiquitous yet understanding the behavioral
effects of them has been restricted by the lack of testable hypotheses
concerning the most basic question: When do we tend to follow streaks
(positive recency), and when do we tend to go against streaks (negative
recency)? From an analysis of positive recency in terms of adaptivity,
I develop two elements of people's representation of the process
generating a sequence which should be predictive of people's use
of positive recency. The first factor is randomness,
which has already been tested empirically, and the second is variability
which is tested here. The context used is stocks because not only
do people seem to give weight to streaks in the stockmarket, but
recent evidence suggests that it may be beneficial to do so. Participants
were told that a small company (more variable price) and a large
company (less variable price) had experienced a streak of six months
of increased/decreased stock prices. As predicted, participants
were more likely to predict that the small company would continue
the streak next month. However, regardless of the initial streak,
participants tended to switch which company would do better between
six months and ten years. The results show that there are interesting
behavioral phenomena associated with streaks". |
Heuristics
as beliefs and as behaviors: The adaptiveness of the "hot hand",
Burns, 2004
"Belief in the "hot hand" in basketball suggests
that players experiencing streaks should be given more shots, but
this has been seen as a fallacy due to Gilovich, Vallone & Tversky's
(1985) failure to find dependencies between players' shots. Based
on their findings, I demonstrate by Markov modeling and simulation
that streaks are valid allocation cues for deciding who to give
shots to, because this behavior achieves the team goal of scoring
more. Empirically I show that this adaptive heuristic is supported
by the fallacious belief in dependency, more so as skill level increases.
I extend the theoretical analysis to identify general conditions
under which following streaks should be beneficial. Overall, this
approach illustrates the advantages of analyzing reasoning in terms
of adaptiveness". |
Randomness
and inductions from streaks: "Gambler's fallacy" versus
"Hot hand", Burns, 2004
"Sometimes people believe a run of similar independent events
will be broken (belief in the "gambler's fallacy"), but
other times that such a run will continue (belief in the "hot
hand"). These opposite inductions have both been explained
as due to belief in a law of small numbers. We argue one factor
that distinguishes these phenomena is people's beliefs about the
randomness of the underlying process generating the events. We gave
participants information about a streak of events, but varied the
scenarios such that the mechanism generating the events should vary
in how random participants judged it to be. A manipulation check
confirmed our assumptions about the scenarios. We found that in
less random scenarios participants were more likely to continue
a streak". |
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