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Explanations, the availability heuristic, and biases of subjective likelihood in economics
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Explanations, the availability heuristic, and biases of subjective likelihood in economics
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EXPLANATIONS, THE AVAILABILITY HEURISTIC, AND
BIASES OF SUBJECTIVE LIKELIHOOD IN ECONOMICS
by
Joshua Christopher Lee
A Thesis Presented to the
FACULTY OF THE GRADUATE SCHOOL
UNIVERSITY OF SOUTHERN CALIFORNIA
In Partial Fulfillment of the
Requirements for the Degree
MASTER OF ARTS
(ECONOMICS)
August 2001
4
Copyright 2001 Joshua Christopher Lee
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UMI Number: 1409595
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UMI
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Copyright 2002 by ProQuest Information and Learning Company.
All rights reserved. This microform edition is protected against
unauthorized copying under Title 17, United States Code.
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UNIVERSITY OF SOUTHERN CALIFORNIA
The Graduate School
University Park
LOS ANGELES, CALIFORNIA 90089-1695
This thesis, w ritten b y
Under the direction o f h ...h S. Thesis
Committee, and approved b y a ll its members,
has been presented to and accepted b y The
Graduate School, in p artial fulfillm ent o f
requirements for the degree o f
Master of Arts in Economics.
Joshua C. Lee
Dean o f Graduate Studies
August 7 . 2001
C hai rperson Timur Kuran
ft • ^ c J l
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Table of Contents
Part I iii
Chapter 1 l
Real Versus Economic Humans: Nuances of Rationality
Chapter 2 6
W hat Do We Mean Bv Anomalies?
Chapter 3 1 4
W hat Is Availability?
Chapter 4 29
The Social Implications of Availability
Chapter 5 3 7
Experimental Caveats
Chapter 6 4 4
Explanations, Availability, and Frequency Bias
Part II 5 4
Chapter 7 55
Experimental Procedures, Results, and Discussion
Chapter 8 7 0
Conclusions
Works Cited 7 8
Appendix 8 2
ii
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P a rti
A R eview o f Literature
iii
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Chapter 1
Real Versus Economic Humans: Nuances of Rationality
W hat sets neoclassical economics apart from other disciplines in the
social sciences is, to paraphrase anthropologist Alexander Moore, the
presum ption that a person makes decisions according to a framework of
rationality as a means to the end of utility maximization. The defining
characteristics of this "rationality framework" usually include, am ong others,
the following tenets: 1) perfect foresight with no uncertainty (people know
exactly w hat is going to happen for the rest of time), and 2) no computational
constraints (people can effortlessly solve the utility maximization problem)
(Hopkins 1998).
Although these latter suppositions seem extrem e when put forth so
bluntly on paper, the neoclassical economic m indset which incorporates
them often appears quite reasonable, especially w hen applied by successful,
sensible businessmen and "experts" on our local news programs. But to
appreciate what incredible peculiarities the fram ew ork gives rise to, a simple
allegory is immensely illustrative.
Imagine two individuals, Homo Sapiens and Homo Economicus, walk
into a bar. Both order the same S3 drink and pay w ith S10 bills and both are
mistakenly returned $8 in change by the preoccupied bartender. W hen the
[
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two customers realize w hat has just occurred, they find they have a choice, to
return the extra change or to keep it. While the implications of keeping the
change m ight be negligible for one or two people, we can imagine both
Homo Sapiens and Economicus realize they may not have been the only ones
given excess change. They may think about how the bartender m ust have
been mistaken on num erous occasions, which in turn m ight make him
suspicious of other customers, and so take extra precautions that foster a less
sociable environm ent in the bar. The costs to the economy of spending more
on security measures, of better training for bar staff, and of customers having
to walk or drive to a more friendly bar may not come readily to your mind as
implications of keeping extra change, but at some level, they are.
A lthough this lengthy consideration on the part of Homo Economicus
is typically glossed over in economic textbooks to save on time, the authors
of such texts w ould not, if pressed, deny that such a process occurs. Nor is
the difference between economically rational m an and real man, as we know
him, embodied in different considerations of w hat impact their change-
keeping decision might have. In fact, the difference is this: neoclassical
economists believe that, however numerous the factors affecting a decision
may be, a person can resolve them into an equation which has a solution that
person will arrive at. A real hum an being, having no time for such
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deliberation, especially over something of such minimal im port as one dollar
spare change, makes use of mental shortcuts also known as heuristics, to
arrive at an appropriate decision.
W hat is remarkable is how closely decisions made by real people
using such abbreviated mental processing mimic those an economically
rational person would m ake using a much m ore thorough, mathematical
process. Naturally then, w hat interests economists are deviations in this
similarity between the judgments of Homo Sapiens and Homo Economicus.
To be functional, heuristics must serve us well, that is help us to act in a way
most people most of the time consider decent and sensible. But, they m ust
also of necessity be quite broad in scope, because the more specific heuristics
become, the more of them there m ust be to deal with all the decisions a
person makes every day. And this impinges on their timesaving purpose. It
is this generality that leads to the curiosities we observe in real people's
thought processes.
There is a reasonably large and growing literature on the various
failures of Homo Sapiens’ judgm ent to conform to that of Homo Economicus.
The works comprising this body reveal an interesting dual trend of heuristic
decision making. Namely, it seems that some judgm ents are legitimately
biased toward inefficient outcomes, and there is room for intervention to
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improve our choices. But, also m any judgm ents typically dismissed by
neoclassical economists as irrational turn out to be quite productive in the
intricacies of hum an interaction. In the case of the excess change above, for
instance, it may be that Homo Economicus elects to keep the change while
heuristic use leads Homo Sapiens to return it. The first character has
determined that the probability that such a transaction will occur many times
multiplied by its social cost is smaller than the zero cost utility gain he
obtains from the extra dollar. The second character's choice may reflect an
heuristic like "The Golden Rule," by which he considers the social costs that
may be brought on by dishonesty greater than a one dollar utility gain.
Now, you may be thinking that I've said Homo Economicus considers
every possible option and is able to resolve them into the best response, and
so he must be right and Homo Sapiens wrong. But there is one vital element
that was left out of the above comparison that reveals w hy this is not the
case. Homo Economicus is assum ed to be able to solve a decision problem
instantly and without effort. A real person does not have this luxury and
exhaustion is a real possibility in a lengthy deliberation, the avoidance of
which is a benefit that m ust be weighed against the cost of giving up the
dollar. Thus, it is Homo Economicus' phenomenal advantage in mental
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prowess that precludes his being a good model to which real man should
aspire.
Once we take into account the power heuristics have in assisting m an
to conserve the precious resources of time and energy, we can see the
advantage of a model of economic rationality that incorporates them. It is
im portant to keep in m ind that this line of research does not so much
challenge the usefulness of neo-classical economic assum ptions as it does the
scope of their implications. The evidence explored below does not point to a
new theory of rationality. Rather, it points to a m ore expansive one.
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Chapter 2
What Do We Mean By Anomalies?
The first order of business in understanding the implications of this
research is to get an idea of w hat is m eant by "anomalies" and the kinds of
problems being tackled by social scientists in this area. Aside from
demonstrating the significance of the issues this research is trying to resolve
and their implications for the discipline of economics, when the w ord
"anomaly" crops up in subsequent chapters of this paper, the reader will
have some idea of the kinds of things neoclassical economists have labeled
this way.
C. Camerer and Richard Thaler, in a recurring article on anomalies,
note that, "Economics can be distinguished from other social sciences by the
belief that most (all?) behavior can be explained by assuming that agents
have stable, well-defined preferences and make rational choices consistent
with those preferences in m arkets that eventually clear (209-220)." Actions
that deviate from this strict definition are considered in economics as failings
of human rationality rather than of the model. One such anomaly, Thaler
points out, arises in the Ultimatum Game. The empirical results of this
experiment deviate rem arkably from the predictions of game theory, and can
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be explained neither by the size of monetary stakes involved nor by the
cultural background of the subjects.
Whereas game theory foresees self-interest w ith the proposer offering
the smallest allowable increm ent and the responder accepting, the reality is
that offers tend to gather around 50%, with offers below 20% largely refused.
Fairness rather than self-interest seems to be the operative rule, as even w hen
one subject plays the dictator whose offer m ust be accepted, the responder
receives a substantially larger chunk than the infinitesimal increment
conventional economics suggests.
Thaler's conclusion is that the idea of fairness m ust be incorporated
into the game theoretical fram ework to make it more viable. For although
models devoid of this concept can predict fair offers made by the proposer
(who learns to make them as stingy ones are repeatedly turned down), no
such model can account for unfair offers being rejected.
The importance of a m ore expansive approach to economic modeling,
particularly one inclusive of psychology, can be seen even outside the
pseudo-reality of experiments. Richard Thaler, in " Psychology and Savings
Policies," addresses a very specific policy concern, the low savings rate of
Americans, by proposing an overhaul of the life-cycle hypothesis of saving
(186-193). This hypothesis assum es that people, having perfect foresight and
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an infinite capacity to process even complex problems, can optim ize their
life-time consum ption by actually solving the "problem" of saving. Thaler
points out the difficulty of conceiving of m an w ith unbounded cognitive
abilities required by this framework, and instead proposes using some
psychological principles to get people to act as though they are optim izing
rationally. Self-control, he suggests, is the problem facing m ost savers,
because they lack enough of it.
Observing the several ways in which this problem distorts saving
behavior, Thaler concludes that, to be effective (elicit behavior more in line
with life-cvcle predictions) a good saving policy should a) provide
immediate rew ard to saving, b) be simple to use and to understand, c) have
the money be perceived as off-limits, and d) encourage experts to consider
the program a good deal. In this case, psychology does not serve so much to
replace the given economic model, as to take advantage of the way people
behave and respond to certain cues to produce actions the given model
considers rational. Optimization, Thaler states, is a result m ore descriptive
of people's behavior in Tic-tac-toe than in chess.
Continuing in this vein, Daniel Kahneman and Richard Thaler tackle
the question of how to increase worker satisfaction with pay packages (341-
347). They "argue for a richer and more psychologically realistic
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characterization of the quality of experiences that includes the following
additional factors: adaptation, contrast, interpersonal comparisons, loss
aversion, and fairness." Advocating an early concept of utility, which they
refer to as experienced utility (that associated with the pleasures of
consumption) as superior to that used more frequently in economics,
decision utility, the authors put forth suggestions to deal w ith each of the
problems noted above. They conclude that, using psychological principles
and without substantially altering costs to firms or requiring extraordinary
measures, not only can worker satisfaction be increased, but the economy as
a whole may benefit. The simple act of labeling certain pay a bonus, for
instance, makes it less onerous to reduce or eliminate during recessions,
thereby allowing firms the ability to lower costs w ithout increasing
unemployment.
Do Experts Succumb to Bias Like the Rest of Us?
The finding that psychology has applications in real-life economic
situations is a significant one. Of perhaps greater interest, however, is the
necessity of augm enting economic theory with psychology to explain even
the behavior of experts in the real world because, as it turns out, they too
display "irrationality". W orking on the finding that stock m arkets tend to
"overreact", Richard Thaler and W erner De Bondt found that "investors were
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reacting to each other during these crashes, rather than to hard economic
news (52-57)." They conducted an experiment to test the judgm ent of
security analysts whom , because their jobs and reputations are at stake, they
rightly deem to have become "experts" in their field. The question w as if
people better educated in economic realities w ould display the same biased
judgments of outcome probabilities as naive subjects recruited for college
experiments do. As it turns out, security analysts are extremely likely to
overinflate their confidence in the performance of companies based on
information too shaky to merit such strong conviction. In the words of the
authors, the analysts are also "decidedly human".
Do Children Exhibit the Same Biases as Adults?
An im portant benchmark in the support of any theory is
dem onstrating its use by children. The reason is that applicability to adult
behavior, while still very useful and interesting, raises the question of
whether the behavior in question might be acquired through socialization.
The assum ption that underlies testing children is that they have had much
less time to be socialized. As such, the behaviors they exhibit are more likely
part of an evolutionarily hardw ired process.
Mary Davies and Peter White, although not draw ing this latter
conclusion, did perform such an experiment testing for use of availability in
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young children (503-505). Using a version of Kahneman and Tversky's
famous names paradigm that substituted cartoon characters for celebrities,
the authors found that children recalled a majority of names from the more
"famous" character list and subsequently found these, erroneously, to be
more common (Availability 163-179). Interestingly, although this paper does
seem to lend credence to availability, it is not entirely clear how robust the
results of the research are.
In the pilot study, children were sam pled to compile lists supposedly
constituting more and less fam ous characters for use in the study. Because
such characters exist only in television programs, they actually possess a
frequency of occurrence defined by how many times they appear on
television. The names on the lists used for adults in this names experiment,
in contrast, are famous in more vague ways than cartoons, perhaps because
of achievements or a high-profile event they were involved in. Because of
this, in the adult version of "fam ous names", subjects would not confuse the
fame of the individual with his or her frequency of occurrence.
But, in the child's version, young subjects might have guessed names
on one or another list to be more com m on because they actually are, that is
because they do in fact occur m ore often for the children, on television.
Because the fame of cartoon characters is so closely tied to actual frequency
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of occurrence in the daily life of child subjects, children guessing the m ore
"famous" nam es on a given list to have occurred m ore frequently w ould, in
some sense, have given the right answ er to the w rong question.
Kahneman, Knetsch, and Thaler take up the question of irrationality
in the marketplace in their paper "Fairness as a Constraint on Profit Seeking"
(728-741). Carrying out a carefully w orded survey, they undertook to
discover how people's notions of fairness m ight explain one of the most
important economic phenomena being scrutinized today: why "patterns of
sluggish or incomplete adjustm ent [are] often observed in markets." While
their main conclusion is that firms perceived as dealing "unfairly" are
sanctioned economically in the long run, the story is actually far more
intricate.
Making use of the psychological concept of adaptation, touched on
earlier in this review, the authors found that judgm ents of w hat is unfair
hinge on reference prices or wages that have little to do with objective justice
and more to do with what people are used to. That is, a price rise for a snow
shovel in a blizzard is seen as unfair because it is not accompanied by an
equivalent increase in costs for the firm and denies consumers their "right" to
the reference price.
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W hat's more, the authors found that firm s could alter these reference
prices based on how they 'fram ed' them, another psychological
phenomenon. For instance, the people polled alm ost unanimously decried a
5% pay cut as unfair, even during an economic dow nturn. But, if the
company said it w ould raise wages by 5% instead of the usual 10%, this was
acceptable, even though it involves the same m agnitude of loss. Firms that
refrain from raising prices even in the face of backlogged dem and or which
decline to reduce employee wages under conditions of high unem ploym ent
may be even more savvy than if they held strictly to neoclassical economic
rationality. The authors' finding that "fair behavior is instrumental to the
maximization of long-run profits" suggests that rationality in firms' m arket
behavior may not be absent so m uch as different from what economics
predicts.
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Chapter 3
What Is Availability?
Already one sees the value of extending the dom ain of economic
theory to encompass the psychology of decision making. This inclusion
allows for certain behaviors typically dismissed by neoclassical economists
as "anomalies" to be explained and extend our understanding of w hat
constitutes human rationality. O f course, to simply review a num ber of
instances when psychology lends a hand in explaining deviations from
m ainstream economic predictions is not the point of this paper. Rather, the
focus is on one aspect of hum an cognition that has been show n to lead to
some important judgmental biases. This key figure in economic decision
making is the availability heuristic.
The Preeminence of Availability
Why study the availability heuristic and not some other such as
representativeness or anchoring and adjustment? In a recent paper on
"Availability Cascades and Risk Regulation" Timur Kuran and Cass
Sunstein explain the preeminence of the availability heuristic as follows: "In
social contexts where people, lacking reliable information of their own, look
to others for interpretations of events... information does not influence
individual perceptions unless it becomes available in the public dom ain (683-
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768)." Because, as the authors insist, the other heuristics (representativeness,
anchoring and adjustm ent, etc.) depend in their functioning on social
interaction, "the availability heuristic necessarily interacts with all the other
heuristics and biases."
Moreover, the im proper use of availability, the primary topic of Kuran
and Sunstein's paper, can lead to dram atic and costly misallocation of
resources, some historical instances of which include the Alar scare and the
implementation of the Superfund following the Love Canal incident. In both
cases, substantial loss of money resulted from erroneous claims of toxins in
the environment, claims perpetuated by repetitious and overwhelming, but
false, public statem ents that became highly available to a critical mass of the
populace.
According to Daniel Kahneman and Amos Tversky, heuristics are
mental shortcuts, which the mind has at its disposal to lighten the task of
otherwise daunting mental calculations a person faces every day (Judgment
3-23). The availability heuristic in particular is heavily involved in
judgments of frequency or class size. An appealing example of how this
heuristic operates shows up in the recent film "Scream". One of the
characters says to another, "You can only hear that Richard Gere gerbil story
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so many times before you have to start believing it." The implication here is
that the more often one hears something, the likelier it becomes.
The actual m echanism supposed to be at w ork can be sum m arized as
follows: the more readily experienced instances of an event come to mind,
the greater the frequency of that event is judged to be. Or, for an event that
has never been experienced, the more easily instances of its occurrence can
be imagined, the greater the subjective frequency becomes. Availability is a
complex process including such manifestations as biases in effectiveness of
search (e.g. when a person believes w ords beginning with 'k ' are more
common than those w ith 'k ' in the third position, though the converse is
true) and illusory correlation. But, in every instance, the action of this
heuristic distills to the two forms listed above, the only significant difference
being whether or not the event whose frequency is being judged has been
experienced by the agent or not.
Limits of the Availability Concept
How careful does one have to be using the term 'availability heuristic'
or even accepting its existence? John Jonides et al., in their paper
"Availability Heuristic in Judgments of Set Size and Frequency of
Occurrence", were concerned with just this question (448-475). Specifically
the authors sought to clarify the legitimacy of behavioral explanations based
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on availability in light of experimental evidence that another mental process
might be operating.
Referring to a review by Hasher and Zacks, the researchers note that,
when estimating frequency of occurrence, subjects may not use actual recall
of instances in the way typically associated with availability (106-116). W hen
tested using a variant of the famous names experiment, subjects m ade
estimates of the proportion of male to female names highly correlated w ith
the actual num ber of male or female names they had heard, even though
they were unable to specifically recall a significant num ber of the nam es
themselves (Availability 163-179). The researchers speculate therefore, that
subjects did not use availability to determ ine the proportion of male to
female names in a numerical tally sense (i.e. actually recalling the exact
names and dividing them into two columns to mentally observe which had
more "tallies"), but instead used availability to "feel out" which class of
names was the larger.
The distinction here is subtle but important. In the first case, we could
ask subjects to write dow n the names they recalled and w ould expect more
of the famous ones to occur and then for the subject to guess there were more
such names. In the second, subjects m ight not actually recall any names or
even have a good idea how many of each there might be, but would guess
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that the set of all male or female names (and we w ould predict which it
would be according to which we had biased with greater fame) to be larger
than the other. In short, one could say this is akin to looking at two jars of
coins and, w ithout actually being able to say how m any cents are in a given
jar, guessing that the fuller one was more valuable. The authors stipulated
that this effect would be even more pronounced w hen more a n d /o r less-
easily defined categories (to which names or other exemplars could be
assigned) were used because subjects would be increasingly dependent on
recall (through which availability operates).
To be perfectly accurate then, the scope of availability's effects should
only be said to affect judgments of class size rather than frequency per se.
But, this difference is more likely to matter if subjects are pressed to give
responses according to a strict definition of frequency than when asked
generally how likely some event is or how often it occurs.
Concerned with the robustness of the availability concept, Colin
MacLeod and Lynlee Campbell undertook a rigorous clarification of the
operation of this heuristic in their paper "M emory Accessibility and
Probability Judgments" (890-902). They propose three criteria, which can be
derived from the basic definition of the availability heuristic and must serve
as the m inim um proof of its functioning. Essentially these criteria condense
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to the idea that anything done to alter the availability of something in
memory must correlate and be proportional to any alterations found in
probability judgments based on that memory. It should be noted here that
these authors assert that the typical definition of availability actually refers to
accessibility of memories as opposed to absolute quantity of information in
the brain. Naturally that is the definition used here.
The reason MacLeod and Cam pbell chose to verify availability
according to more stringent criteria is the questionable nature of earlier
associations of experimental results w ith the action of this heuristic. In the
original famous names experiment by Kahneman and Tversky, although it
was dem onstrated that memory m anipulation could alter subsequent
probability judgments, it remained unclear w hether this occurred because of
a change in the relative ease of recall (accessibility) or some other m echanism
(Availability 163-179). Additionally, experim ents such as that of Shedler and
Manis, in which subjects were given tw o different kinds of information about
two different groups of exemplars to see how this affected frequency
estimates, left unanswered the possibility that memory manipulations m ight
influence recall and judgment independently (26-36).
The real problem with previous experiments is that, contrary to
recommendations by Tulving and Pearlstone, the conditions of the
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experiment were not held constant up until the m om ent of recall (381-391).
Some of the confusion may very well have to do with semantics of the
definition of availability versus accessibility: in Shedler and Manis' study,
accessibility may have been m anipulated, but so was availability, the actual
am ount of information in memory. Because som e exemplars had w ritten
and photographic associations, this could have constituted greater
availability of these in the encoding phase of m em ory so that one could not
say that probability judgm ents based on them w ere influenced because of
ease of recall or because they had in some sense been experienced more.
Keeping these problems in mind, the authors constructed a recall
experiment based upon the famous names m odel but modified in several
ways to control for availability alone and not som e other mediating factor.
They used mood m anipulation to enhance exam ples' salience because this
would not add any information to the object itself to be memorized and
hence would not make it m ore available. Rather it should be more
accessible. What they found was that indeed m anipulated samples were
recalled more readily (judged by speed of recall). More importantly,
however, the manipulation of recall was correlated with subsequent
probability judgments (happy mood led to faster recall of positive events
which led to higher subjective likelihood of such events, etc.).
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Interestingly, MacLeod and Campbell found this correlation to be less
significant than anticipated and suggest that this may have to do with the
m easure they chose for availability. Specifically, they use recall speed
whereas other researchers have used recall accuracy or a different criterion.
The importance of this for future experimental design cannot be trivialized.
As the authors suggest, just exactly how different types of memory
accessibility affect judgm ent is ripe ground for exploration.
In a 1996 paper, "On the Reality of Cognitive Illusions", Kahneman
and Tversky were compelled to address a more fundam ental attack on the
use of the terms 'heuristic' and 'bias' (582-591). According to G.
Geigerentzer, "biases are not biases and heuristics are m eant to explain what
does not exist (83-115)." His essential claim is that judgm ents of probability
(on which the concepts of availability and other heuristics depend) have no
m eaning because probability is subjective and so cannot be generalized or
applied to unique events. He also insists that if probability is interpreted as
"long-run relative frequency, then cognitive illusion disappears."
In plain English, Geigerentzer is implying that one could not, say, give
the probability of the 49ers winning the Super Bowl, because such an event
never occurs the same way twice, and so there is no basis for definitive
frequency of winning or losing. And, he claims that if people are asked to
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make estimates by saying, "H ow many times out o f is this likely to
occur?" instead of, "W hat is the probability of this?" then the biases
researchers observe them making will disappear.
With a convincing discourse, Kahneman and Tversky reject
Geirgerentzer's critique. Generally, they state, people do have a common,
shared understanding of probability and find it meaningful to communicate
with it. They can and do also make predictions, such as that a person is less
likely to die within a week than within a year, which are predicated on
Baysian rules that Geigerentzer rejects. More im portantly though, the
authors point out the large body of research in which subjects were found to
be prone to predictable judgmental biases that did not disappear even when
problems were formulated in terms of frequency.
Salience; Availability's Partner in Crime
What makes an event more or less available is clearly integral to the
predictive power of theory based on this heuristic. M. Durham and Clark
McCauley believe that vividness or salience is a key factor in enhancing the
availability of a memory (138-148). W orking on the premise that personal
experience would provide a relatively high degree of salience, they sought to
demonstrate bias in the frequency judgments of dialysis patients regarding
the success rate of kidney transplant surgery. It is im portant to note, as these
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researchers did, that the personal experience of the patient alone (n = 1) does
not constitute an appropriate random sample from which statistically
meaningful conclusions can be draw n. They insist that, if the patients'
thinking were unbiased, there should be no difference in the success rate
judgments between successful and unsuccessful transplant patients. In fact,
quite a different result was obtained.
Controlling for selective exposure (i.e. successful patients spending
most of their time with other successful patients), Durham and McCauley
found successful transplant patients giving significantly higher estimates of
the success rate for such an operation than unsuccessful patients gave.
Ostensibly personal experience made the outcome of surgery for the patient
him /herself the most accessible in memory, which skewed estimates of
frequency of success in the direction of the outcome of their ow n operations.
The researchers emphasize the non-trivial nature of the frequency estimation
task for these "subjects"; because transplant surgery had an immediate
impact on their lives, an accurate assessment of the risk involved would be a
major factor in their decision to undergo it. A bias in this judgm ent could
clearly lead either to unnecessary risktaking or to refusal to undertake a
reasonable risk.
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Continuing the focus on salience, Rodney Triplet provides another
example from the realm of medicine (303-322). Conducting a survey of
attitudes tow ard patients with various symptoms of disease, Triplet
speculated that the notoriety of AIDS in the media and the sheer
commonness of influenza would bias subjects to find these more indicative
of the sym ptom s they read about than Leukemia, even when either disease
was equally likely. Moreover, Triplet sought to show how the ultimate
choice of which disease subjects believed a patient had led to biases in their
actual behavior.
When AIDS was contrasted with Leukemia or influenza, subjects were
much more likely to choose AIDS if the patient in question was homosexual.
Heterosexuality made influenza the likelier diagnosis. Then, contrasting
AIDS with influenza, subjects were much more likely to hold AIDS victims
personally accountable for their condition than influenza sufferers. Believing
these results to stem from the availability of instances of AIDS associated
with homosexuality in the media, Triplet bolstered this hypothesis by
showing that even lesbians were seen as more likely having AIDS, when in
fact they are not a known risk group. The media, believes Triplet, which
uses the term 'homosexuals' generally, could have caused this bias by not
specifying males.
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A final piece of research by Dollinger, Greening, and Pitz on
"Adolescents' Perceived Risk and Personal Experience W ith Natural
Disasters" brings up an im portant point about salience (27-38). These
authors tested subjects in a real-life setting, which they felt to be significant
because, unlike in an experimental environm ent, "daily experience varies far
more dramatically in memorability than experimentally induced stimuli", so
availability may show up in recall of som e events and not others. W hat the
authors seemingly found was that, natural disasters personally experienced
resulted in much greater clarity of m em ory than those that people had
simply heard about. This in turn led to the finding that only those disasters
personally experienced showed evidence of the operation of availability on
subjects' judgments of the likelihood of these events occurring again. For
disasters subjects had experienced second hand, the authors cite the effects of
the "sim ulation heuristic" on biasing likelihood judgments compared w ith a
control group.
While this suggests a fascinating possibility of salience cutoffs for the
use of the availability heuristic, it also begs further inquiry into one aspect of
the definitions of the various heuristics. The operation of the so-called
"sim ulation heuristic" is so similar to the second of the two ways availability
is said to operate (the creation of relevant instances when the answer cannot
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be known by definition or personal experience) that it could possibly be
subsumed under the umbrella of availability. In that case, availability would
have factored into all probability judgments of experimental subjects in this
research. It is only that, in the case of the personally experienced natural
disaster it was observed operating in the first of its tw o modes, through
actual recall and not construction of exemplars.
Availability and Imagination
Stephen J. Hoch, in his article "Availability and Interference in
Predictive Judgm ent", returns to the question of how, exactly, availability
operates tlirough recall to influence likelihood estim ates (649-662). In this
case, Hoch focused on the second mechanism of availability, the construction
of relevant instances in memory w hen the "answ er is not known by
definition." In a m anner similar to that in research presented earlier, Hoch
studied the effects of imagining self-relevant scenarios on perceived future
likelihood of the event. The unique spin of his particular article, however,
was the emphasis on how pro-instances may have interfered with con-
instances generated in memory.
Questioning subjects as to the reasons they could conceive of to buy a
camcorder, Hoch found that this thought process inhibited the ability to
immediately come up with reasons not to buy the camcorder. This, he
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hypothesized, had at least two possible explanations. One is that the act of
recall itself is a source of forgetting, creating w hat he terms response
competition whereby the first thoughts that occur have their association with
the object strengthened through the sheer act of generating them. The
second possibility is that subjects may be attem pting to maintain cognitive
consistency, only "willing to interpret relevant information from one
perspective," and so not contradict themselves.
Though Hoch's experiment, which show s that introducing a delay
between generation of one type of reason (pro or con) and the other
practically eliminated inhibition of the second type of reason, suggests the
first hypothesis is likely correct, it does not obviate the need to look into the
second. It may be that the two work hand in hand, with initial generation
strengthening associative bonds causing the subject to settle on one reason as
his or hers to defend, and cognitive consistency compelling the subject to
subsequently bias judgments to be in line with this initial hypothesis.
This second of the two ways in which the availability heuristic
operates is the cornerstone of this research. In a paper titled "Support
Theory: A Nonextentional Representation of Subjective Probability", Amos
Tversky and Derek Koeler make perhaps the m ost significant observation
about this correlation between availability and imagination (547-567). They
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state, "that probability judgments are attached not to events but to
descriptions o f events." Kahneman and Koeler find that subjective likelihood
increases with the "explicitness" of such descriptions, a phenom enon we
have already learned to call "salience."
It is this very aspect of hum an cognition that leads to vivid
charaterizations of some events being more available even than others which
logically subsum e them (as w hen a person believes it is more likely their
car's battery will die than any part of the "electrical system" because the
former term is m ore explicit than the latter), the essential premise of support
theory. The prominence of this relationship between descriptions of events
and their availability will be m ade clearer shortly.
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Chapter 4
The Social Implications of Availability
Looking at the mechanics of the availability heuristic as a mental
process, it is easy to lose sight of the fact that it is more than a quirky
theoretical construct. That being the case, it is im portant to take a brief look
at some of the substantial and socially relevant implications of availability
and bring the discussion back into the realm of perceptible happenings that
affect the reader.
An intriguing question about availability is raised by Russel
Eisenman's paper on the "Belief that Drug Usage in the United States is
Increasing When it is Really Decreasing" (249-252). The conclusion he draw s
from a fairly basic survey of perceptions of drug usage is that people tend to
believe drug usage in the U.S. is on the rise when in fact, he states, it is
declining. Eisenman implicates the media as the likely culprit of enhanced
availability of drug usage in the U.S. Comically, it may well be that the
perception that the media is responsible for this effect is also the result of an
availability heuristic, since this is a popular explanation in the scientific
community studying this area. If the conclusion is robust, it has significant
implications for governm ent policy.
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Availability may be m ore pronounced in some situations than in
others. For instance, in Robert Agans' and Leigh Schaffer's research on the
Hindsight Bias, it seems availability use is m uch more difficult to avoid
when people know the outcomes of events whose probabilities they are
asked to estimate (439-449). That is, w hen people are given a description of
the characteristics of an event and told that it did occur and then are called
on to predict the likelihood of that event occurring under similar
circumstances, they tend to overestimate this likelihood. W hen they are only
given a description of an event and not told whether or not it occurred,
people make likelihood judgm ents much more in line with actuarial data.
Agans and Shaffer sought to show that outcome data m ade the
occurrence of a given event a certainty in the minds of subjects, which
prevented a further search of memory. Thus, the events said to have
occurred became the most available, and their subjective probabilities
increased. The danger with this, as the authors see it, is that a) decision
makers may wrongly be deem ed incompetent for not having seen w hat
subsequently became obvious and b) people may not learn m uch from the
past. Perhaps more appropriately for economics though, is the serious
misallocation of resources that can occur because of this bias. Specifically,
the authors determined that people's perceptions of the risks of three life
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threatening events were exactly opposite the statistical evidence. This may
mean that people expend a great am ount of time and money avoiding a
relatively less likely homicide and very little dodging the bullet of heart
disease.
A very high-profile instance of availability's application in the legal
arena came not long ago. In their article "What Are Nice Feminists Like You
Doing on the O.J. Defense Team?", Geraldine Stahly and Lenore W alker
discuss how availability and group identity conspired to make the O.J.
Simpson m urder trial a battle of black versus white versus wom en (425-439).
The authors stipulate that the vastly different historical experiences
blacks and whites have had with institutions such as the police, and the
prominence of such personal experience in their memories led each to weigh
opposite aspects of the evidence in deciding O.J.'s guilt or innocence.
Harassment by police led blacks to focus on the possibility of police
misconduct, w hereas white wom en saw the racism issue as a ploy to take
attention off of a know n batterer who, in their eyes, was unw orthy of a legal
defense. Interestingly, the authors found this latter belief so pronounced that
even statistical evidence showing low likelihood of battering behavior
leading to later m urder was going to be brushed aside.
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A brief work by Thomas Young and Laurence French even found the
availability heuristic inside the boxing ring (310). Using a Wilcoxian rank-
sum test, the authors discovered that, in ranking the "greatest boxers of all
time", the availability of more recent boxers in m em ory may have led to a
significant overrepresentation of these in the final tally.
Even religion has been scrutinized for intriguing decision patterns. In
the paper "Invoking Naturalistic and Religious Attributions", Michael
Lupfer and Elizabeth Layman dissected subjects' "explanations of behavioral
events" to determine w hat cognitive strategies m ight be at work (55-76).
Subjects, it seems, are able to reach conclusions about the nature of an event
much more rapidly when its salient features are either highly representative
or highly unrepresentative of a possible explanation. When an event's
classification as either naturalistic, religious, or non-religious
supem aturalistic was more opaque, subjects took longer to decide.
Of particular note is the authors' finding that, when subjects
ultimately settled on a religious explanation, they did so in much less time
than when choosing a naturalistic one, which, incidentally, they did most
often. The authors only speculate at why this m ight occur, but the fact that
the subjects, from most to least conservative, favored religion most to least,
respectively, may offer insight. It could be that m any people are conditioned
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in their youth to automatically attribute some events to divine influence
unquestioningly. This would cause an imm ediate response of "religion"
when prom pted w ith the right target questions. With inquiries they are
untrained in, however, a longer process of com parative analysis is required.
Those subjects who rated themselves as m ost conservative and who
subsequently found religious explanations relatively more compelling, m ight
be expected to have a larger, and so more available, store of events which
they have been conditioned to associate w ith religious forces.
In "Differential Use of the Availability Heuristic in Social Judgment",
Rothman and H ardin take for granted that people are conscious strategic
users of their mental faculties in judgm ent tasks and seek to enliven the
debate over the role of applicability of information in mediating use of the
availability heuristic (123-138). Identifying three different target groups for
social judgment, the self, the in-group (relatively more like the self), and the
out-group (relatively less like the self), their general results show a curious
peak-vallev-peak pattern of heuristic use in social judgment. They find
heavy reliance on subjective ease of recalling behaviors (i.e. availability use)
to rate the self and the out-groups as possessing these behaviors, but
virtually zero reliance on ease of recall and instead reliance on sheer volume
of information in judging in-groups.
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Rothman and Hardin found that for close friends num ber of behaviors
recalled became more im portant than ease of recalling them and vice versa
for casual acquaintances. The authors suggest that this occurs because
heuristic use (ease of recall) is m ore heavily associated w ith feeling-based
judgments, something they say is more characteristic of interactions w ith
close friends than with casual acquaintances. The astute reader will notice a
seemingly paradoxical flip-flop here. Namely, why is it that the type of
judgment used with close friends should differ from that used w ith the in
group? It seems almost too obvious that close friends should be the
quintessence of in-group, though the evidence contravenes this notion.
Clues as to what might be behind the strangeness have been
identified. The authors suggest that heuristic use is characteristic of
judgments of close acquaintances because it is closely linked w ith emotional
reaction. It may likewise be the case that emotional reaction is m ore
characteristic of out-group judgm ent than in-group judgm ent because out
groups tend to provoke prejudice and stereotyping, things which help
separate the two types of people. That being the case, heuristic use would
show up in both out-group and close friend judgments largely because of
emotional factors absent in judgm ents of casual acquaintances and in
groups.
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Because the research presented in this paper makes a point of
validating the results obtained by m anipulating diagnosticity of ease to the
judgm ent task, a possible explanation for w hat helps define a person as part
of an in- or out-group and more precisely w hat decides if availability is or is
not used in evaluating them may be suggested by this process. That is, the
authors found that, w hen the ease of recall was rendered non-diagnostic to
judgment, number of behavioral instances recalled was used to evaluate
everyone, regardless of the group they had previously belonged to.
Rothman and H ardin intimate that it is habitual use of either ease or
num ber in recall with regard to the various groups that normally decides
whether or not ease is diagnostic in judging them. So we could say, that
differences in how a person evaluates a close friend versus a casual
acquaintance, or the self versus the in-group versus the out-group is a m atter
of habit. We could further determine that this habit facilitates differences in
judgm ent of close friends versus the in-group and casual acquaintances
versus the out-group by observing to whom a certain form of judgm ent is
habitually applied.
This piece of work raises all sorts of questions and is clearly repleate
with important issues to be resolved. The shift in the type of information
and way it is used between the in-group and out-group is a dram atic one
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and has potentially major consequences for social perceptions and later
interactions. As such, one expects a pressing question to be w hat exactly
defines someone as part of an in- or an out-group. And, more fascinatingly,
at w hat point in repeated, long-term interaction does a person shift from one
category to the next? One w onders also if this shift and the corresponding
change from ease to numerical recall devices in judging the person changing
categories is a gradual one or happens suddenly.
At this point it should be more obvious to the reader why the study of
availability is significant, not only for the scientific comm unity, but to the
community at large. While som e of the topics noted above are only
tenuously related to the discipline of economics, there are many that are very
intimately entw ined with it. Nevertheless, the point of the latter digression
was to show the transcendence of this heuristic beyond the boundaries of
any one field of study and dem onstrate its relevance in a num ber of social
areas.
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Chapter 5
Experimental Caveats
The reason some economists dismiss attempts at incorporating
psychology into their field as a waste of time is the same reason those of us
who try to do this anyway m ust be careful in formulating o ur experiments.
That is, it is very difficult to quantify, specifically to use mathem atical
equations to model, hum an thought processes. Therefore, the procedures of
any experiments used to study such processes must be very tightly
constrained lest they be left open to extremes of interpretation. Indeed, as
will be seen in the brief discussion below, even some very prom inent
experiments have, despite seem ingly simple and well-controlled design,
been left open to reinterpretation.
What Controls Subjects' Perception of Experiments and H ow Important is
this Perception in Determining the Results of a Study?
That the availability heuristic operates in hum an judgm ent rarely
comes under fire. But, there is an intensifying assault on the soundness of
experiments that have ostensibly dem onstrated this action. It seems some
researchers are all too ready to make attributions to availability in their own
work based upon paradigm s that, at best, only coincidentally gave results
substantiating availability. Reicher, Stapel, and Spears look to the famous
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names experiment as the basis for their case on behalf of im proved
experimental design (141-158).
The original notion of availability posits that "classes whose instances
are easy to imagine or recall will be perceived as relatively frequent." In
their updated studies, Reicher et al. em ploy a num ber of creative devices to
ensure that the results confirm this specific definition. For in exam ining the
seminal work of Kahneman and Tversky, they discovered that the w ay in
which the experiment was presented, m ore than biased use of an
inappropriate judgmental shortcut under uncertainty, m ight have been the
reason for the results obtained.
In their discussion, the authors point out evidence that in fact subjects'
perception of what the task will be as m uch as or more than its complexity is
a determ inant of whether or not subsequent judgments will be biased and
how. They point out that one flaw in previous experimental design has been
ambiguity in the definition of uncertainty suggesting that, at the same time
researchers are defining it as sensory load, they are also introducing a second
form of uncertainty as to the m eaning of the task at hand and that it is this
latter definition which may cause the bulk of biased judgment.
The authors go so far as to suggest that subjects' use of availability'
may be less automatic than a calculated reactive application to maximize
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information uptake for w hatever they believe to be the task. The puzzle
arising from this w ork is not only multifaceted but controversial in the
heuristics and biases school. In particular, it challenges some researchers'
belief that people by and large are at the mercy of mental shortcuts like
availability rather than deliberate users of them.
More than suggesting the disappointing possibility that as much of
the value of availability experiments like famous names is in dem onstrating
that people can be sw indled into inappropriate use of heuristics as in saying
anything about the existence of the heuristic itself, subsequent reanalysis has
revealed a num ber of features of such early research that lead to much
sounder experimental design.
To begin with, Stapel et al. found through interviews that most
subjects' initial perception of the task in the famous names experim ent was
that it was a test of general memory in which they focused on fame as a hook
to assist in recalling as many names as possible. This raises two questions.
First, why were subjects convinced that the experiment w as concerned with
memory? Though the authors suggest that the instruction "listen
attentively" may clue subjects into the possibility that they may be asked to
later recall w hat they hear, other explanations seem equally plausible. Listen
attentively might just as easily be a command indicative of a hearing test, for
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instance. Perhaps subjects' previous experiences w ith various kinds of tests
dispose them to approach a judgm ental task in a certain way. Because of the
seeming preeminence of this phase of the experim ent in determ ining the
results, it seems imperative that the nature of the m echanism that controls
task perception should be uncovered.
The second question raised concerns the subjects' focus on fame as the
memory hook they would use to increase their chances at recall. Looking at
the famous names paradigm, two obvious categorizations of the items on the
list come to mind: gender and fame. In Stapel et al.'s studies, which repeat
the experiment several times, it becomes clear to subjects that one of these
categories is, in fact, a red herring, and they go on to revise their approach to
recall. What is curious, however, is why they chose to focus on fame rather
than gender in the first place. Every name on the list w ould have a definite
gender, but might not be considered to possess m uch fame. That is, gender
is a definite, but fame is a m atter of degree. It w ould be interesting to
uncover whether it was this or some other nuance of definition that made
fame the more appealing memory enhancer than gender.
Exactly when subjects formulate their strategy for w hatever they
guess the task to be would be a valuable discovery as well. For example, if
subjects are told "listen attentively to the following list of m en's and
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wom en's names," then the category of names had already been read off.
Then perhaps people use the given information, prior to the onset of the
judgmental problem, as a baseline and look for w hat is unusual am ongst the
characteristics possessed by items on the lists to assist in storing and using
information to make judgments or predictions. An obvious choice m ight be
those things, like fame, only revealed after the experiment is underw ay. It
may well be that people are disposed to categorize, and the trick of
experiments such as the famous names one is m anipulating hoiv people
categorize and what information they see as relevant to the task.
Whereas Reicher et al. made attem pts to mediate the misuse of
availability by making people aware of categories like fame they might
wrongly attach themselves to, I believe a more drastic alteration of the
experimental procedure is in order to really witness judgmental mechanisms
in the raw. Such revamped design might modify the famous names
experiment by eliminating fame, using absolutely generic male and female
names and then moderating w hat information about the task is given up
front to see if people's choice of recall cues does in fact depend on differences
in information. That is, experiments could say simply "listen attentively", or
"listen attentively to this list of m ale/fem ale names" to see if in the latter
case gender does become the recall hook.
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Alternatively, categories could be completely elim inated by m aking
lists comprised of som e names of people, some of objects, some of concepts
(e.g. love, beauty, etc.). Then one could uncover more about w hy certain
features (as fame) seem more readily used to assist memory than other
alternatives (as gender). A variation of this might seek to more clearly reveal
if the decisive factor in choosing a recall hook is whether or not the class is
yes/ no (again as gender) or has some sense of degree (again as fame).
But, perhaps the most significant remake of the famous names
experiment would give no instruction at all to subjects before simply leading
into playing the names on the tapes. In such a case, experimenter dem and
would not be a factor at all, and interviews asking what subjects' perception
of the task was and how they approached it could shed a great deal of light
on whether or not people do indeed strategically employ judgmental tools
according to perception of task as these interviews would generate a 2
column table of task/response, which w ould be used to evaluate
appropriateness of the latter for the former.
Despite the num erous opportunities for extended research stemming
from the reexamination of the famous nam es experiment, the point being
made is that these arise from the reality that many facets of the original
research were not appropriately controlled for. Though it naturally is not
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alw ays possible, the ideal would be to try to account for the various
contingencies of an experiment, such as those uncovered by Reicher, Staple,
and Spears, before carrying it out. Then, all the exciting extensions to the
w ork can be made immediately or at least acknowledged from the outset so
they do not become problematic when others notice their absence.
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Chapter 6
Explanations. Availability, and Frequency Bias
"I used to wonder," says Robert Ciaidini, "Why big com panies such
as Proctor & Gamble and General Foods are always running those '25-, 50-,
or 100 w ords or less' testimonial contests (Commitment, 57-113)." H e was
talking about those events, basically essay contests, in which a com pany
solicits people to write a statem ent praising one of its products. W hat was
especially perplexing to Ciaidini was that these companies invariably
rew arded the winners of these contests with pretentiously huge prizes,
sometimes worth tens of thousands of dollars. Moreover, they are often
open even to non-consumers of the product, as no purchase is required to
enter an essay.
Likening these product testimonials to an interrogation tactic used by
the Chinese on American POWs during the Korean War, Ciaidini finally hit
on the purpose of them. W hat these essays accomplish is to get hundreds of
thousands of people to "go on record" as liking the product. Amazingly, it
doesn't seem to matter that m any of the people entering the contest do not,
in fact, like the product or at least are indifferent about it. As will be show n
momentarily, the act of explaining why you believe som ething tends to bring
your actual beliefs strongly in line w ith this explanation, even w hen they
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started off contrary to it. Moreover, as your beliefs change, your actions are
very likely to follow.
The economic significance of this phenom enon are well known to the
firms m anipulating it. Despite the daunting odds contestants face against
winning the prize being offered, they nevertheless participate in droves,
because the cost of w riting an essay is usually quite small when com pared
with the potential return in the form of a luxurious reward. W hat many of
these people do not realize, however, is that it is not the essays companies
like Proctor & Gamble are after, but rather the significantly higher likelihood
that contest entrants will buy their product after having described how good
it is. This expanding business more than makes up for even very costly prize
offerings!
Although several studies suggest a strong link between availability in
recall and subsequent estimates of frequency, the possibility that availability
ultimately influences behavior remained undeterm ined. A carefully crafted
experiment conducted by Kathleen Carpenter, W. Larry Gregory, and Robert
Ciaidini shows, in addition to num erous other significant findings, that it is
indeed the case; availability can ultimately alter one's actions (89-99).
Following the structure of earlier research by J.S. Carrol, these authors
had subjects imagine themselves in scripted scenarios and then give
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estimates of the likelihood they would really enact such a scenario (88-96).
Going even further, Carpenter et al. then observed actual behavior of
subjects who were placed in the scenarios they had vicariously experienced
through imagination. The experiments conducted show that indeed, not
only does imagining oneself in a scenario increase the subjective likelihood
of it occurring, but increases the actual likelihood of it occurring as well.
Similar to Agans' and Shaffer's explanation for the hindsight bias,
Carpenter et al. conclude that imagining an event occurring may make its
occurrence a certainty in the minds of subjects, precluding a search for
alternative explanations, and ultimately m aking that event's occurrence the
most available scenario that comes to m ind (439-449).
The other results obtained in assuring the validity of this series of
experiments are at least as interesting as the conclusion. The authors
questioned if possibly imagining anything m ight make the likelihood of a
specific event more likely. So, controlling for this in one variant, they found
that only the event imagined influences the self-relevant likelihood of that
event occurring. In a second variant, the authors controlled for the effects of
experimenter demand. Here too, they found that the experimental setting
alone cannot account for the results obtained. All of this strengthens the
validity of the availability explanation.
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In a follow-up to the paper "Does Imagining Make It So?", (89-99)
Robert Ciaidini, Steven Sherman, and others discuss the role of availability in
perceptions of the likelihood of contracting a disease (Imagining, 118-127).
Ciaidini et al. focused on the second of 2 mechanisms by which availability is
believed to operate. That is, rather than look at ease of retrievability of
memories already formed, they studied the effects of ease of constructing
images of events with which subjects were unlikely to have had experience.
The hypothesis is that people use the ease or difficulty of constructing an
image of an event as an indication of that event's likelihood.
Indeed, the results in this paper indicate that subjects who w ere asked
to imagine contracting a disease with very concrete, easy to visualize
sym ptoms rated such a disease as relatively more likely than a disease whose
sym ptoms were quite vague. That subjects in the difficult to imagine
condition gave lower likelihood estim ates than the controls again show s that
the simple act of imagining anything cannot account for enhanced
availability of a specific scenario; imagining a difficult concept actually
suppresses likelihood estimates for that concept.
The implications of this paper are again more profound than the basic
findings. For instance, the researchers point out that, "Because unlikely
events are typically difficult to retrieve or explain, subjects may infer that if
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an event is difficult to explain or imagine, then it m ust be unlikely. " This is
a similar source of bias for several judgm ent scenarios (see Robert Cialdini's
book "Influence: The Psychology of Persuassion, especially pages 5-6 and 10-
11 for a good elaboration of this topic). The mind takes a life lesson, valuable
w hen applied in one direction, and reverses it, introducing a sometimes-
faulty reasoning. The point most relevant to this thesis, though, is that "the
availability of any outcome should increase if one has recently predicted,
imagined, or explained it" and that "once a plausible cause for an outcome
occurs, subjects no longer engage in search procedures that m ight implicate
other causes."
Further insight into the mechanics of the explanatory act is offered by
Craig Anderson, Mark Lepper, and Lee Ross (1037-1049). Intrigued by the
observation that people seem to draw conclusions from scanty evidence and
to stick to their guns even when their ideas have been thoroughly
discredited, the authors sought to uncover the workings of this process.
They used two fictional case studies dealing with applicants for the job of
fireman. For each, subjects were told either that the applicant's propensity to
take risks had made him a successful candidate or had been the cause of his
lack of success as a fireman. The subjects were then asked to write out an
explanation of why this connection between risk-taking behavior and later
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success (or lack thereof) should exist. Following this explanation, the
subjects were asked to evaluate several additional applicants for the position
of fireman and judge the likelihood of their success considering their own
tendency to take risks.
The crux, of course, is that even though subjects knew the information
in the case studies was fictitious before m aking their judgments, the
subjective likelihood assigned to the success of candidates for firemen was
biased in the direction their experimental condition suggested. That is,
results were biased up when subjects were told risk-taking behavior was a
positive factor in their case study's career as a fireman and biased dow n
when they had been told it was a negative factor for the case study in the
same job.
Substantially the same results are found from a study by Lepper et al.
in which subjects were asked to write explanations identifying "potential
antecedants" to a given behavior on the part of an individual described in a
case study (817-829). When asked to estimate the likelihood of similar others
performing this behavior, subjective likelihood was observed to increase
relative to a control. This effect again persisted even when the hypothetical
nature of the case studies was made explicit from the outset of the
experiment.
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Several intriguing findings arise from these latter experiments. First,
subjects are shockingly ready to make serious generalizations from the barest
minimum of data, i.e. one or two cases! Second, it does not m atter at all
which side of the argum ent subjects are asked to endorse, that willingness to
take risks makes one a successful or unsuccessful fireman, the results are the
same. This second observation is particularly striking w hen one considers
that different groups w ere looking at exactly the same case studies and were
simply told to draw different conclusions from them.
Again in the second study, though the case studies read were the
same, regardless of experimental condition, subjects seem ed able to draw
from them whatever conclusion they were instructed to find, leading them to
alter frequency judgm ents for vastly different behaviors ranging from
donating to the Peace Corps to committing suicide. Looking at exactly the
same biographical information, subjects were able to convince themselves
that this information w ould lead to even mutually exclusive events.
When Harriet Shaklee and Baruch Fischoff undertook a variant of the
above experiments, they found that bias exists also w hen events described
are mutually sufficient (520-530). The significance of this is that, when a
person is deciding between m utually exclusive causes of an event, once one
of them has substantial support, it is reasonable to stop searching for
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confirmation of the opposite alternative because it is already ruled out by the
occurrence of the first. W hen possible causes of an event are mutually
sufficient, however, proving that one such cause is very likely does not allow
a person to stop searching for evidence of the others, because they all could
play a hand.
Despite this logic, when subjects in this study were presented w ith an
event and several possible sufficient causes, one of which was implicated by
a certain fact, the subjects preferred to gather more information about the
implicated cause than any of the others. Branded "truncated search," this
pattern of thinking about information was observed even when one of the
possibly sufficient causes was said to be a certain factor in an event's
occurrence. In that case, gathering more information about that cause does
not reveal anything more about w hat specific possible cause resulted in the
event. Nevertheless, subjects continued to prefer to gather more information
even about this strongly implicated cause than about the others, som ething
which could have helped them confirm or disconfirm their choice.
Each of these papers leaves room for m ultiple possible explanations.
According to Anderson, Lepper, and Ross, these include a "classic
dissonance or self-perception process," whereby subjects attem pt to m ake
self-consistent statements in the form of biased frequency judgments
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following the explanation they had given and mentally embraced as their
ow n (1037-1049). Scripting, in which an explanation of a social process leads
a person to create a "script" of events, which they use to anticipate how the
social process will unfold in future encounters, is also implicated. And,
finally, there is the possibility that the act of explanation increases the
availability of the mechanism described such that it is easier to retrieve than
unexplained alternative mechanisms and leads to the belief that the form er is
likelier than the latter.
Clearly it is this final possibility that I endorse in my own research.
The experiments to follow are in part concerned with establishing the role
availability plays in frequency bias through explanation. There is, however,
more to be said than simply w hat mental process is involved in the bias
observed. There may, it will be recalled, also be a physical m echanism
involved. In the first two papers noted above, the procedure involved
writing explanations of a certain event. This is extremely im portant because
earlier research suggests that w ithout the act writing, the key experimental
manipulations do not work. None of these latter papers establishes w hat
format explanation must take to produce the results they all deal with.
Moreover, in the Anderson, Lepper, and Ross paper, the authors
discovered something very perplexing in the writing procedure they
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em ployed (1037-1049). Namely, they found that som e of the subjects did not
actually describe a pathw ay from willingness to assum e risk to success as a
fireman, but instead simply stated that willingness to take risk led to such
success (or lack thereof). They did not supply a line of reasoning why this
should be so. Nevertheless, the biasing effect was observed in the predicted
direction for these subjects as well. This, according to the authors, should
not technically have occurred since the subjects did not really do what they
were asked to do. Rather, it would appear that subjects may not need to
write out a logical causal path from some action to some consequence; they
may simply have to believe they are constructing such a path in their
writing.
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Part II
Experimentation
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Chapter 7
Experimental Procedures and Results
The research here encompases two experim ental procedures, the first
consisting of two control and four experimental groups, the second
comprising one control and one experimental group. Moreover, the first
experiment is concerned with establishing the physical mechanism, which
explanation m ust employ to be effective, as well as m easuring the potential
influence of availability in the explanatory act. The second experiment deals
with expounding on Anderson, Lepper, and Ross's finding, that logical
explanation does not seem to be a prerequisite for biasing frequency
judgments.
Experiment 1: Procedure
This first experiment used six groups of 10 subjects each. All groups
were given two excerpts to read from a case study of Yanomamo Indians by
Napoleon Chagnon, one describing a passive male nam ed Kaobawa, and a
second describing an aggressive male named Rerebawa. Each group was
named according to the excerpt they read first, e.g. aggressive control.
In all groups, the subjects were ultim ately given an eight item
questionnaire to fill out at the experiment's conclusion. These questionnaires
asked about the likelihoods of various scenarios involving both aggressive
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and passive Yanomamo males, w ith all aggressive or all passive questions
coming first depending on w hether the subjects had read the aggressive or
passive excerpt first. Each question was followed by a visual analog scale,
essentially a line exactly 10 cm long and ranging from "not likely" to "very
likely". Subjects were instructed to m ark along this scale their belief in the
likelihood of the scenario described in the preceding question. It was
intended that such a scale would allow subjects more freedom to express
their feelings than would a discrete num ber scale, although practical
m easurem ent limitations compelled rounding subjects' marks to the nearest
millimeter.
In the 4 experimental groups, following the reading of the excerpts
but preceding the questionnaire w as a statem ent that either Kaobawa or
Rerebawa had become chief of the tribe. The experimental subjects were
then instructed to explain how either Kaobawa's passive or Rerebawa's
aggressive behavior had allowed him to achieve the position of chief. The
key variable distinguishing the 4 groups was the form that this explanation
assum ed. For two groups it was written, while for the other two it was
verbal explanation that was requested. The control groups were sim ply told
that one or the other man had become chief of the tribe and were then given
the questionnaire straightaway.
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For all six subject groups there were two key observations to be made.
First, I was interested in the ratings each subject gave on one of the eight
questions, the third one, which asked, "How likely do you think it is that a
Yanomamo male w ith a passive (an aggressive) nature would become chief
of the tribe." The expectation w as that, for those subjects who had m ade an
explanation of how Kaobawa's passive or Rerebawa's aggressive nature had
led him to become chief w ould find it much m ore likely that another passive
or aggressive male, respectively, would become chief of the tribe than would
the corresponding control.
The second key observation involved m easuring the speed w ith which
subjects came to their likelihood decision on this third question. I postulated
that this speed was intimately linked with the speed with which subjects
could recall the explanation they had made, a ready response that would
allow them to make a faster judgm ent call on the questionnaire than would a
control subject who had no such explanation handy. To pursue this
observation, all subjects in the 6 groups were timed on every question from
they time they began reading the questionnaire.
After answering all questions, subjects were thanked for their
participation and informed that they would be debriefed fully the following
week. Because of the order in which subjects volunteered for the
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experiments, some groups consisted alm ost entirely of females or males, so
demographics were ignored.
Experiment 1: Results
Using independent sam ple t-tests, I com pared the measures of
subjective likelihood in the critical question, "H ow likely do you think it is
that a Yanomamo m an w ith a passive (an aggressive) nature will become
chief of a village?" Looking at the m ean subjective likelihood values, both
the passive and aggressive written explanation experimental groups showed
significant difference from the corresponding controls (t(18,12.685)=-5.329
p=0.0001 and t(18,15.270)=-2.948 p=0.01, respectively).
Effectively, w hat was dem onstrated here is that those who explained
an event were more likely to believe that it w ould occur than those who
m ade no explanation. In fact, because of the level of significance (the tests
were conducted at the 5% level so there is a 95% that the results obtained are
accurate) we can be confident in the biasing effect w ritten explanation
induces.
For the subjects in the aggressive verbal explanation experimental
group (values for the passive verbal group were unavailable for this analysis)
there was also a significant difference in mean subjective likelihood (t(18,
16.988)=-3.551 p=0.002) relative to the control. The difference in the mean
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subjective likelihood values between written and verbal experimental groups
was, however, not significant.
In the latter case, we can see that not only is verbal explanation
effective in biasing peoples beliefs in the likelihood that the event they
explained will occur, it is equally so effective as w ritten explanation. The fact
that there was no significant difference in the m agnitude of subjective
likelihood bias caused by written and verbal explanation confirms this latter
supposition. The idea of a sliding scale for the strength of the biasing effect
can be dismissed at least for written versus verbal mechanisms.
Looking at the mean differences in speed of recall (as measured by the
time each subject required to reach a conclusion on the subjective likelihood
of the event in the critical third question), only the passive written
explanation group was significant (t(18,17.021 )=2.3 p=0.034).
The above finding is som ewhat more difficult than the others to
interpret. Because there were no substantial differences in the subjective
likelihood bias generated in the passive and aggressive conditions, it is hard
to surm ise why one would show up for speed of recall measures. While
significant, the speed of recall differences even for the passive written
explanation group were not as robust as the subjective likelihood bias.
Recalling Lvnlee Campbell and Colin MacLeod's speculation that the less-
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than-anticipated level of significance from their ow n m em ory accessibility
experiments m ay have stemm ed from their choice of "speed of recall" as the
measure of availability, I propose that my use of this m easure combined with
the relatively small size of my subject pool facilitated the am biguous findings
discussed above (890-902). Given at least a larger sample population, I
expect there would be significant differences in speed of recall for all
experimental groups.
Experiment 2: Procedure
The second experiment was designed to answ er a question raised by
Anderson, Lepper, and Ross's study (which used a similar case
study/questionnaire format). In that study, several subjects, failing to follow
instructions (to actually explain how the behavior of the people described in
the case studies they read led them to become successful or unsuccessful
firemen), still showed the same bias as those subjects who perform ed as the
researchers had intended. Specifically, some subjects in Anderson, et al/s
study wrote something to the effect of, "Risk taking behavior makes a person
a successful (or unsuccessful) fireman," a mere restatem ent of the question
rather than a coherent explanation of hoxv risk taking behavior m ade for
success or lack thereof.
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This second experiment thus sought to determine if subjects could
indeed show biased subjective likelihood estimates regardless of w hether
their explanation ought to merit it logically. Since I could not count on
subjects failing to follow instructions as had some of those in Anderson, et
al.'s experiment, I had to force some subjects to write an inappropriate
explanation and try to convince them that they were in fact w riting one that
ought to lead to the bias observed in the first experiment.
In this case I used only the description of the aggressive Yanomamo
male, Rerebawa. Following the reading of the excerpt, subjects w ere asked
to write an explanation (the verbal group was discarded for this variant) of
how Rerebawa's behavior could be taken as aggressive (the control group) or
as passive (the experimental group). Following this explanation, subjects
were told that, among Rerebawa's people, passive males typically become
chief of the tribe. Finally, subjects were asked to mark along a visual analog
scale, identical to those in the first experiment, their belief as to how likely it
was that Rerebawa would become chief of the tribe.
The observation of interest was the likelihood subjects in the different
groups assigned to the outcome that Rerebawa became chief of his tribe. For
the control subjects, who had described Rerebawa's behavior in the obvious
way, as aggressive, I presumed they would find this rather unlikely. If the
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Yanomamo select principally passive m ales as their chiefs, then someone as
blatantly aggressive as Rerebawa should be an obviously poor choice for this
position. I hoped the experimental group subjects, however, w ould find the
contrary to be true. If the pow er of explanation is truly great, then it will
override even the description of Rerebawa so patently averse to being
labeled passive. In that case, the subjects will be able to draw a confirmatory
decision from disconfirmatory information.
Experiment 2: Results
Again using independent sample t-tests on the mean differences of
subjective likelihood, it was found that these differences were significant
(t(18,10.774)=-3.250 p=0.006). Interestingly, several subjects in this
experimental variant also failed to follow the instructions exactly giving the
opposite results expected. Despite this fact, the results were significant
overall, and when these subjects were excluded from the analysis, the
significance was simply stronger (t(13,11.071)=-13.339 p=.0001).
For written explanation then we can, again with (95%) confidence, say
that there is a very powerful biasing effect. Indeed, what has actually been
dem onstrated is that people need not even be provided with legitimate
evidence from which they could logically draw a certain conclusion to go
ahead and draw that conclusion anyway. T hat is, even w ithout an iota of
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passivity in the description subjects were given of Rerebawa, they were,
following their w ritten explanation, able to conclude that he was passive
enough to become chief of his tribe. Subjects' belief in the integrity of their
argum ent was enough to allow explanation to bias their belief in the
subjective likelihood that Rerebawa would ascend to be chief of a tribe
clearly sanctioning people with personal qualities nothing like his own.
G eneral D iscu ssion
The first experiment m ade two interesting clarifications to the
previous research on biases resulting from explanation. Namely, I found
that both written and verbal explanation suffice to produce frequency bias.
But, more importantly, there seems to be no substantial difference in the
effectiveness of one form of explanation vis a vis the other.
Looking at Cialdini's example of product marketing, it is likely verbal
testimony would produce much the same sort of results as the essay contests
typically employed. Noteworthy in this is the fact that subjects in the verbal
conditions spent m uch less time (roughly half as much) formulating their
explanations than did those in the written condition while still producing
comparable effect on their beliefs in the likelihood of the event in question.
Why any sort of biased belief occurs at all was clearly the question of
greatest import in this first experimental procedure, but unhappily remained
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largely a question since the results were conflicted. There did appear to be a
increase in the speed with which subjects in the passive written condition
were able to answer the question regarding the likelihood of the passive
Yanomamo becoming chief relative to the passive control. This could
indicate that an answer to the question was more readily available to them,
facilitating an easy and rapid response.
The observation that the aggressive written and verbal experimental
groups did not show a significant increase in speed of answering the target
question is perplexing. A possible variable affecting the successful
measurement of speed differences was the procedure used for timing
subjects' responses. Because it was not feasible to use a one-way m irror or
some other discrete procedure, the tim ing was unfortunately invasive (the
stopwatch beeped noticibly every time a response to one of the questions
was clocked). Occassionally a subject would stop at the critical question to
laugh or make a comment about the timing, thereby throwing off its
accuracy. A few times this occurred in the aggressive experimental groups,
which could account for the insignificance obtained in the t-tests for these
subjects.
One finding, which is expeciallv difficult to interpret is the lack of
correlation between bias and speed of recall even for the passive written
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group that had show n a significant increase in this speed (Spearm an's rho
Correlation Coefficient = 0.432 p=0.213). Because we expect the explanations
to lead to positive bias in subjective likelihood and also for that bias to be
indicated relatively more rapidly by those making the explanations, we
likewise anticipate a correlation here. Probably this boils dow n to difficulties
in tim ing and the som ewhat small num ber of subjects available for each of
the 6 groups being timed.
In any case, there are clearly some suspicious findings here that, given
a larger subject population and a less invasive timing mechanism, are ripe
for clarification. A speculative suggestion would be that under m ore
favorable conditions a correlation between speed of recall and bias does
indeed emerge and, more generally, that we would witness significant
differences in speed of recall for the aggressive group when com pared with
the control.
The performance of the second experim ent was obviously m ore
agreeable, even considering the num ber of subjects who failed to follow the
directions exactly- That subjects were able to develop biased subjective
likelihood from explanations so clearly opposed to this outcome, is full of
implications.
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This procedure was designed to have people draw conclusions not
simply about a scenario only tenuously related to the explanations they
wrote, but in fact to draw conclusions about a scenario diametrically
opposite w hat they explained. Using the aggressive stimulous excerpt,
which hasn't even a modicum of modest behavior in it, subjects were
nonetheless able to conclude that it was in fact passive behavior being
described. And they went on, in half the cases, to show the appropriate bias
based on this conclusion.
As a nod to those who complain that psychological experiments are
out to prove hum an beings the hapless slaves of ingrained mental processes,
it should be noted that half of the subjects did not do what they were told.
Looking at the explanations of this group, it was found they had all said
som ething to the effect of, "This m an's behavior m ight be taken as passive
because of some cultural nuance, but objectively he was really very
aggressive." They thereby contaminated the process by explaining to
themselves that aggressiveness was the m ain characteristic evinced in the
excerpt and so were in line with the controls in finding it unlikely for the
Yanomamo man described to become chief of the village.
There is certainly a great deal of room for im provem ent both in the
scope and quality of the experimental procedures undertaken in this
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research. Apart from a more discrete timing procedure and a generally
larger applicant pool, there are several other changes that would enrich the
topic of interest here.
To begin with, Anderson, Lepper, and Ross note three possible sources
of the bias inherent in explaining an event (1037-1049). Scripting and
cognitive consistency were not tackled in my work. Since the m ost that can
be done in looking at the working of availability as I have is to disprove its
role, because this did not occur, it is im portant to look at the action of the
other two possible mechanisms of bias to weed out the real culprit. A clever
experimental setup m ight incorporate two of the three (or even all three
together) mechanisms in such a way that the results would clearly determ ine
that availability and not scripting or cognitive consistency was causing the
bias apparent in my experiments.
Then, since part of the reason for the som ew hat blase findings on
availability's role in my experiments might, as Campbell and MacCleod
suggest, have to do with my choice of speed of recall as the m easure of
availability, it would be a good idea to run the tests again substituting other
likely measures such as accuracy of recall (890-902).
A more varied subject pool might also be as much of interest as a
larger one. Particularly, since all of the participants in my experim ent had at
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least one year of college education, it seems im portant to look for differences
in how vulnerable individuals w ith less and more schooling were to
succumbing to bias. O ther dem ographics such as gender and age could also
contain intriguing trends.
Part or all of the results the experiments presented here may have
depended on experimenter dem and. There is really nothing w rong w ith this
in the sense that many of the scenarios in the market place where
explanatory bias does come into play also make use of someone consum ers
recognize as an authority figure making the request for an explanation.
Nevertheless, it would be a significant finding that revealed just how m uch
coaxing a person needed to subject himself or herself to an action that could
substantially alter their beliefs and behavior. Judging by the impersonal
nature of General Mill's essay contests and their implied success, it seems
that the presence of the authority figure is probably not important.
Finally, because as an economist I am chiefly interested in the
economic ramifications of the availability heuristic, the next logical step
would be to revise the format of the experiments to deal directly with
specific economic scenarios. For this research, I was after the effects of
general principles of likelihood bias derived from availability use, therefore I
deem ed it unnecessary to use experim ental stimuli based on economic
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examples and instead chose my topical material from anthropology. In
subsequent experiments I should choose rather to test for the action of
availability, subjective likelihood bias, speed of recall, etc. as they apply to
precise economic circumstances such as saving behavior, investment
management, and macropolicy. Such experiments need not deal solely with
revealing the presence of an availability induced bias, but could also test the
effect of some of the remedies for economic problems discussed in the next
section.
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Chapter 8
Conclusion
Being a m ultidisciplinary study, it is easy to lose sight of the economic
roots and implications of the research presented here. It is thus im portant to
return to these at the conclusion of the paper and suggest w hat role the
results of these experiments m ight play in some im portant economic
problems discussed earlier.
In the first chapter, I m entioned the dual trend of heuristic decision
making, one aspect of which was that some judgm ents we, as normal
humans, make are legitimately biased toward inefficient outcomes. In these
cases there is room for intervention to improve our choices. One of the
examples of this kind of faulty decision-making is the low savings rate of
Americans studied by Richard Thaler.
Thaler's argum ent was that it was lack of self-control that led
consumers to put so little away and suggested, as two of the characteristics
necessary to remedy this, having the money be perceived as off-limits and
encouraging experts to consider the new savings program a "good deal."
One way of achieving these aims, in light of the research presented in this
paper is to make use of the bias inherent in explanation as a m edium to
achieve self-control and a belief that the savings program is a good deal.
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Consumers could be asked to write (or even form ulate verbally, as we
have seen) an explanation of w hy putting more of their income away for the
future is a good idea. They could even be m ade to give a very explicit
account of just how they planned to achieve this goal of higher saving. These
consumers would then be m uch m ore inclined to agree that higher savings
rates are indeed a good idea and, as several research papers covered earlier
in this paper have m ade clear, are much more likely to actually save more.
The explanatory process w ould produce the necessary shift (bias) in
consumers' propensity to believe that they are more likely to save, while the
effect demonstrated by Carpenter, Cialdini, and Gregory would lead to the
necessary bias in consum ers' propensity to actually save more (89-99).
If later research does dem onstrate solidly that availability increases as
a result of explanation, then investm ent experts would do well to intervene
and ensure that the explanations consumers gave of how they planned to
achieve higher savings were, in som e objective sense, the correct ones. Then,
w hen planning financially, consum ers would have a viable program readily
available in their memory and w ould access this easily and preferentially in
their savings decisions.
As for the experts, they too could be asked to explain, only in this case
their explanations would focus on the merits of this approach to bettering
7!
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consum er savings habits. This would encourage them to endorse the policy,
which is something essential to providing the confidence consum ers need to
undertake the policy for their ow n financial activities. One im portant aspect
of this approach to experts is that, if the reasons they could provide for why
they thought the policy would w ork were not w hat the policymaker had in
mind, they w ould still experience the positive bias sought to encourage them
to see the policy as a "good deal" nonetheless, as the second of my two
experiments established.
A similar approach could be used with security analysts, the subject of
the study by W erner De Bondt and Richard Thaler, to innoculate them
against the overconfidence that may lead to coresponding overreaction in the
stock m arket (52-57). W hat De Bondt and Thaler were concerned with was
that, "investors [are] reacting to each other during these crashes, rather than
to hard economic news." One of the problems the authors found at the root
of this was that these analysts were overinflating their confidence in
companies based on very scanty information, so there was no way for them
to predict accurately the direction they would take. Thus, w hen a company
took an unexpected turn for the worse, they had nothing to do but watch
how other analysts responded to the news and react.
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Explanatory bias could be used with these analysts by having them
describe how valuable a m ore thorough study of the companies they track is,
before they invest in them. Moreover, they could be m ade to explain the
minimum and ideal criteria for making im portant investm ent decisions
before they actually undertake this activity. They w ould then be relatively
more likely to follow up on these criteria, being m ore cautious before
engaging in im portant transactions. Also, they w ould be encouraged to
deflate their confidence in their investm ent decisions w hen only the minimal
and not the ideal investm ent conditions had been met.
In Timur Kuran and Cass Sunstein's paper on "Availability Cascades
and Risk Regulation," several instances of costly resource misallocation
attributed to availability are mentioned (683-768). One of these is the Love
Canal incident in which residents of a New York housing com m unity
discovered that the land they were living on had once been used to dispose
of toxic chemicals. Subsequently, they began a cam paign protesting their
living conditions in which every m inor illness from cold to upset stomach
was attributed to environm ental toxins. The culm ination of this activity was
the expensive relocation of all the families in the Love Canal area and the
passage in Congress of the billion dollar Superfund.
Reproduced with permission of the copyright owner. Further reproduction prohibited without permission.
W hat was ironic about the latter situation is that, throughout the
whole episode, num erous EPA tests were conducted of the ground and
water in and around Love Canal, none of which uncovered dangerous levels
of toxins. Yet this reality w as dismissed by reactionary parents and w hat
Kuran and Sunstein call "availability entrepreneurs," as governm ent
propaganda to cover a heinous crime.
In fact, there was nothing at all dangerous about Love Canal, and
whatever merits Superfund m ight be seen to have in retrospect, it began as a
remedy for a non-existent ailment, essentially a superfluous waste of
taxpayer money. Rather than insinuate that my research again has a place in
resolving such a complex problem as was Love Canal, I instead stipulate that
it may elaborate the problem.
Basically, the panic that ensued over the alleged contam ination of the
canal began with one woman, Lois Marie Gibbs. After reading some
senstationalist stories appearing in a local newspaper, Gibbs became
convinced that the area she lived in was contaminated and she w ent on to
organize the fateful protests noted above. Kuran and Sunstein point out that
Gibbs eventually developed a "set speech" that she em ployed in her door to
door solicitations for petitions signatures.
Reproduced with permission of the copyright owner. Further reproduction prohibited without permission.
W hat I am suggesting is that, in the process of formulating this speech
and w hatever other explanations Gibbs used in describing the situation she
believed she was living in, and m oreover in giving this speech, she became
more and more deeply convinced of a cover-up and pollution. Every time
she gave the speech and certainly also if she ever put it to paper, Gibbs
would have biased upw ard her convictions and, at some point, w ould have
found it incredibly difficult to back dow n from them in light of other
evidence, evidence she would have heard or read but not had a hand in
explaining herself and so would not have found as credible.
A similar phenomenon could have affected many of the initial critical
mass of people it eventually required to push Love Canal into the public
discourse, after which point it w ould have been practically self-sustaining.
An obvious proposition to help to control against such a scenario is to make
as m any people as possible aw are of w hat occurs in the mind when
explanations of events are undertaken. The hope, then, would be that,
knowing they are likely to be subjected to biased beliefs, people attem pting
to account for a situation in which they find themselves would carefully
account for this and try to keep in m ind alternative explanations.
This brings us back to the exam ple with which the experimental
section of this paper opened, Cialdini's essay contests. As a consumer, one
75
Reproduced with permission of the copyright owner. Further reproduction prohibited without permission.
can be reasonably certain that General Mills is not the only com pany aware
of the powerful effect explanation can have on our buying tendencies.
Moreover, even if one lived their entire life w ithout coming across an essay
contest like those described by Cialdini, one could be alm ost certain they
would still not have avoided a sim ilar attem pt to influence them using the
principles studied in the experiments of my research.
It is not unheard of for salesmen to request of their prospective
customer that she write dow n all the good qualities or uses that could be
associated with this television or that camcorder, which the salesman is
trying to sell. The unwary consum er need not, as has been shown in the
second experiment, even come up w ith realistic good qualities or uses, for as
long as she believes they are the byproduct of purchasing the item in
question the outcome is the same: a m arkedly higher tendency to buy it.
Being aware of this phenom enon is a good start in protecting oneself
from m anipulative sales pitches like that above. But, there is probably even
more that can be done. Imagine w hat would occur if, instead of immediately
explaining all the good uses that could be found for a new television or
camcorder, the consumer first wrote dow n all those other things for which
the money could be used. It may well be that she still decides to acquire the
item in question, but at least it will not be entirely an impulse-buv since other
76
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options will have been considered. And indeed, a person taking this
precautionary step will have been m uch more likely to postpone their
purchase because of bias favoring alternative uses for the money.
Let me close by reiterating a premise set forth in the introduction to
this paper. Once we take into account the power heuristics have in assisting
man to conserve the precious resources of time and energy, we can see the
advantage of a model of economic rationality that incorporates them. It is
important to keep in mind that this line of reasearch does not so much
challenge the usefulness of neoclassical economic assum ptions as it does the
scope of their implications. The evidence explored above does not point to a
new theory of rationality. Rather, it points to a more expansive one.
Reproduced with permission of the copyright owner. Further reproduction prohibited without permission.
Works Cited
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Heuristic and Perceived Risk." Basic and Applied Social Psychology 15.4:
439-449.
Anderson, C., Lepper, M., Ross, L. "Perseverance of Social Theories: The
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and Hypothetical Explanations on Subjective Likelihood." loum al of
Personality and Social Psychology 61.2:195-202.
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Imagery." Personality and Social Psychology Bulletin 11.1:118-127.
Davies, M., and White, P. "Use of the Availability Heuristic by Children."
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7 8
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De Bondt, W., and Thaler, R. "Stock M arket Volatility: Do Security Analysts
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Durham, M., and McCauley, C. "Patients' Perceptions of Treatm ent for
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Eisenman, Russel. "Belief that Drug Usage in the United States is Increasing
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7 9
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Hopkins, Ed. "N otes On Labour Supply: Topics in Microeconomics."
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Lepper, M. R., Ross, L., Steinmetz, J. L., and Strack, F. "Social Explanations
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Pearlstone, Z., and Tulving, E. "Availability Versus Accessibility of
Information in Memory for W ords." loum al of Verbal Learning and Verbal
Behavior 5: 381-391.
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Choice: Some Moderators of the Availability Bias." European loum al of
Social Psychology 25.2:141-158.
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loum al of Personality and Social Psychology 39.2: 211-221.
Stahly, G., and Walker, L. "W hat Are Nice Feminists Like You Doing cn the
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Thaler, Richard. "Psychology and Savings Policies." American Economic
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Reproduced with permission of the copyright owner. Further reproduction prohibited without permission.
Appendix
Sample Experimental Stimuli and Questionnaires
Folloxving are tivo excerpts from a case study, done by Napoleon Chagnon, of the
Yanomamo Indians of Venezuela. Read each excerpt. Take as long as you need.
Please indicate when you are finished reading and you will receive fiirther
instructions.
"Kaobawa is a quiet, intense, wise, and unobtrusive man. He typically
stayed at the sidelines while others would surround me and press their
demands on me. He instructs more by example than by coercion. He can
afford to be this way at his age, for he gained the respect of the other men in
the village by being honest and humble when he was younger. He also has
five m ature brothers in the village who frequently come to his aid. Kaobawa
has also given a num ber of his sisters to other men in the village and has
promised his young (8 year old) daughter in m arriage to a young man who,
for that reason, is obliged to help him. In short, his natural or 'kinship'
following is large, and partially because of this support, he does not have to
display aggressiveness to rem ind his peers to respect him."
"Rerebawa has displayed his ferocity in many ways, but one incident in
particular illustrates w hat his character can be like. Before he left his own
village to take a new wife in Bisaasi-teri, he had an affair w ith the wife of an
older brother. When it was discovered, his brother attacked him with a club.
Rerebawa responded furiously: He grabbed an ax and drove his brother out
of the village after soundly beating him with the blunt side of the single-bit
ax. His brother was so intimidated by the thrashing that he did not return to
the village for several days. I visited the village shortly after this event with
82
Reproduced with permission of the copyright owner. Further reproduction prohibited without permission.
Rerebawa as my guide. He made it a point to introduce me to this man. He
approached his hammock, grabbed him by the wrist, and dragged him out
on the ground: 'This is the brother whose wife I screwed when he w asn't
around!' A deadly insult, one that w ould usually provoke a bloody club
fight. But, the m an did nothing. He slunk sheepishly back into his
hammock, shamed, but relieved to have Rerebawa release his grip."
Reproduced with permission of the copyright owner. Further reproduction prohibited without permission.
Kaobawa (the man described in the first excerpt) went on to become the chief of the
village in which he and Rerebawa (the man described in the second excerpt) live. On
the paper provided, please describe in writing how you think Kaobawa's passive
nature lead to his success in achieving the position of chief of the village. Feel free to
refer back to the information provided in the excerpts to complete your explanation.
Please indicate when you are finished and you will receive further instructions.
Reproduced with permission of the copyright owner. Further reproduction prohibited without permission.
A t this point you will be asked to answer a few questions about how likely different
outcomes are based on the information you read in the excerpts ab< rve. Each question
is follozved by a scale on which you are asked to place a mark indicating your belief as
to how likely each behavior is. The scale ranges from not likely to very likely and
you may place your mark amjivhere along it or at the ends.
Reproduced with permission of the copyright owner. Further reproduction prohibited without permission.
I. Please mark on the scale heloiv how likely you think it is that a Yanomatno man
with a passive nature would make a good father.
N O T LIKELY [ ________ ] VERY LIKELY
2. Please mark on the scale below how likely you think it is that a Yanomarno man
with a passive nature would commit suicide.
N O T LIKELY [ _______________ ________ _____ _________ ____________________________________ _ _ ] VERY LIKELY
3. Please mark on the scale beloxv how likely you think it is that a Yanomatno man
with a passive nature would become chief o f a village.
N O T LIKELY [ ] VERY LIKELY
4. Please mark on the scale below how likely you think it is that a Yanomatno man
with a passive nature would use drugs.
N O T LIKELY [ _________________________________________________________ VERY LIKELY
5. Please mark on the scale below how likely you think it is that a Yanomatno man
with att aggressive nature would make a good father.
N O T LIKELY [ .___ ] VERY LIKELY
6. Please mark on the scale beloxv how likely you think it is that a Yanomatno man
with att aggressive nature would commit suicide.
N O T LIKELY [ ] VERY LIKELY
7. Please mark on the scale beloxv hoxv likely you think it is that a Yanomatno man
xinth att aggressive nature xvould become chief of a village.
N O T LIKELY [ ________________________________________________ Jv E R Y LIKELY
8. Please mark on the scale beloxv hoxv likely you think it is that a Yanomarno matt
xvith an aggressive nature xvould use drugs.
N O T LIKELY [ ] VERY LIKELY
8 6
Reproduced with permission of the copyright owner. Further reproduction prohibited without permission.
Following is an excerpt from a case study, done by Napoleon Chagnon, o f the
Yanomatno Indians of Venezuela. Read the excerpt. Take as long as you need.
Please indicate when you are finished reading and you will receive further
instructions.
"Rerebawa has displayed his ferocity in many ways, but one incident in
particular illustrates what his character can be like. Before he left his ow n
village to take a new wife in Bisaasi-teri, he had an affair with the wife of an
older brother. When it was discovered, his brother attacked him w ith a club.
Rerebawa responded furiously: He grabbed an ax and drove his brother out
of the village after soundly beating him with the blunt side of the single-bit
ax. His brother was so intim idated by the thrashing that he did not return to
the village for several days. I visited the village shortly after this event with
Rerebawa as my guide. He m ade it a point to introduce me to this man. He
approached his hammock, grabbed him by the wrist, and dragged him out
on the ground: 'This is the brother whose wife I screwed when he w asn't
around!' A deadly insult, one that would usually provoke a bloody club
fight. But, the man did nothing. He slunk sheepishly back into his
hammock, shamed, but relieved to have Rerebawa release his grip."
Reproduced with permission of the copyright owner. Further reproduction prohibited without permission.
On the paper provided, please write an explanation of hoxv Rerebaxva's behavior
could be taken as passive. Take as long as you need. Feel free to refer back to the
excerpt in completing your explanation. Please indicate when you are finished
writing and you xrill be given further instructions.
Reproduced with permission of the copyright owner. Further reproduction prohibited without permission.
A t this point you will be asked to answer a question about how likely a certain
outcome is based on the information you read in the excerpt above. The question is
followed by a scale on which you are asked to place a mark indicating your belief as to
how likely each behavior is. The scale ranges from not likely to very likely and you
may place your mark anyrvhere along it or at the ends.
Reproduced with permission of the copyright owner. Further reproduction prohibited without permission.
Among the Yanomarno Indians, passive males frequently become the chiefs of their
tribes.
1. Please mark on the scale beloxv hoxv likely you think it is that Rerebaxva xvill
become chief of his tribe.
N O T LIKELY [ ] VERY LIKELY
Reproduced with permission of the copyright owner. Further reproduction prohibited without permission.
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Asset Metadata
Creator
Lee, Joshua Christopher
(author)
Core Title
Explanations, the availability heuristic, and biases of subjective likelihood in economics
School
Graduate School
Degree
Master of Arts
Degree Program
Economics
Publisher
University of Southern California
(original),
University of Southern California. Libraries
(digital)
Tag
Economics, theory,OAI-PMH Harvest,Psychology, clinical,psychology, social
Language
English
Contributor
Digitized by ProQuest
(provenance)
Advisor
Kuran, Timur (
committee chair
), [illegible] (
committee member
), Kalaba, Robert E. (
committee member
)
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https://doi.org/10.25549/usctheses-c16-42776
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