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WWWW ' ' I ' IIII IM UMiiii<iijpji|iyipii«|JHUi--.iJuujji iPi|iwi,wu«i>«,p,yi|, jiiiuipuii4iii|iet!<lipi|ip.Wiiy wupy ■KIIU.WiHMW IMI
AD-A008 591
TEMPORAL SETTING AND JUDGMENT UNDER UNCERTAINTY
Baruch Fischhoff
Oregon Research Institute
.
P' spared for:
Office of Naval Research Advanced Research Projects Agency
7 April 1975
DISTRIBUTED BY:
mi] National Technical Information Service U. S. DEPARTMENT OF COMMERCE
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ONR Technical Report
125127
TEMPORAL SETTING AND JUDGMENT UNDER UNCERTAINTY
Baruch Fischhoff
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This research was supported by the Advanced H^mch Projects Agency of thr 8fenso (ARPA Order No. 2^9) ang ^onitired by^NR unde^
Contract No^jg fej3-C-04.td (MR 197-026}.
nt are those of the ssarily represent;« | the the Advanced Research r the U.S. Government
ny purpose of the ites Government.
Research Bulletin Vol. 14, No. K.
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3 RCPOUT TITLE
Temporal Setting and Judgment Under Uncertainty
4. DCSCniPTi VC NOT«» (Typ* ol topotl ond In
Technical Report S. «uTHORItl (Flnl nmir; mlddl* Inlllml, Imtt nmato)
Baruch Fischhoff
• REPORT DATE
April 7, 1975
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13 ABSTRACT
In a series of experiments, subjects judged the likelihood of events set either in the past or the future. No consistent differences were found in either the central tendency or the dispersion of subjects' likelihood judgments regarding past and future events which differed solely in their temporal setting. Temporal setting was, however, found to affect the pro- duction of possible event outcomes. These results contradict a "sure past" hypothesis, which has been advanced by a number of observers according to which judges are more confident in dealing with past than future events. They also eliminate a possible source of methodological difficulty in existing judgmental studies and provide some insight into the use of judg- mental heuristics. Belief in the "sure past" hypothesis is discussed as the result of confusion between temporal setting and its ecological correlates.
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OREGON RESEARCH INSTITUTE
TEMPORAL SETTING AND JUDGMENT
UNDER UNCERTAINTY
Baruch Fischhoff
Oregon Research Institute
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Oregon Research Institute Research Bulletin
Vol. 14 Number 14
1974
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Temporal Setting
2
Temporal Setting and Judgment Uider Uncertainty
Are likelihood Judgments affected by :he temporal setting of
the events being judged; i.e.. by whether those events are set in the past
or future. Aside from its obvious suUtantive interest for the psychology
of time and the study of judg.ent, the answer to this question has methodo-
logical implications for both fields.
Research In Judgment hns typically Ignored the temporal aettlng of the
stlMuli uaed in experimental taaks. A suhstantlal temporal netting effect
„ould »eggest a need to review existing findings with sn eye to the setting
of the stimuli used, and at the extreme, the develcpmant of diatinet pay
chologles of predictive and poetdlctive Judgment. Similarly, atudenta of
peraonal time perapectives (e.g.. Bortner S Hnltach. 1972) have typically
assumed that the past-future differences which they have observed are
exciuaively due to changing persona! and aocia! realities. Eeintarpretation
of their results «ould clearly be called for if temporal aettlng alone were
found to affect judgment.
Considering the many waya in which people's perceptions of past and
future eventa have been found to differ (e.g.. gratfisch. Ekman. lundberg. *
Kruger, 1971; Cohen, 1967, Ekman S Lundberg, 1971, Koriat 4 Fischhoff,
1974), an effect of temporal setting on Judgment seems far from implausible.
Although this possibility has drawn little attention from psychologists.
It has been considered by philosophers and othera concerned with the study
of history. Probably the moat fre,uently raised contention in this prlmsrily
anecdotal literature ia that Judges sre more confident in desling with past
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Tetrporal Setting
3
than with future events. Perhaps the most succinct expression of this
"sure past" hypothesis may be found in Seignobos and Langlois' classic
histuiiographic text, Introduction to the Study of History (1898):
The natural tendency is to forget in [the] reconstruction [of past
events] the results yielded by [scholarly] criticism, to forget the
incompleteness of our knowledge and the element of doubt in it. An
eager desire to increase to the greatest possible extent the art of
our information and the number of conclusions impels us to seek
emancipation from all negative restrictions. We thus run a great
risk of using fragmentary and suspicious sources of information for
the purpose of forming general Impressions just as if we were in
possession of a complete record, (p. 281)
Similar sentiments are readily found elsewhere (e.g., Ayer, 1956; De Jouvenal,
1967; Kissinger, Note 1; Pelrce, cited in Danto, 1965; Polak, 1965;
Toffler, 1970).
The source of reported differences in the judgment Df pagt an(}
future events is, however, often unclear. In each of the cases cited above
(see also Doob's, 1970, compendium), the change in the temporal setting of
the events in question is confounded with other changes likely to affect
judgment.
One frequent source of confounding is that the sets of past and future
events being judged contain markedly different members. Different events
should, reasonably, be judged differently. Even when similar events ^re
being considered, the judges Involved frequently possess outcome knowledge
about the past, but not about the future events; i.e., chey know how the
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Temporal Setting
A
former turned out. Such additional infor lation could reasonably affect
their perceptions. Although frequent, this latter type of confounding is
by no means necessary. There are past events whose outcome is unknown
and future events whose outcome is a foregone conclusion.
Even similar past and future events about which equal information is
available may be judged differently for reasons unrelated to their temporal
setting. Consider, for example, how the following events change in meaning
if they are set twenty years ago or twenty years hence: a trip to your
dentist, a parade of lesbians in the streets of New York, an earthquake on
Alaska's North Slope, writing ycur New Year's resolutions, or being unhappily
married in Italy (before or after enactment of the divorce law).
It is, of course, not changes in temporal setting which are responsible;
for these changes in meaning, but contemporaneous changes in relevant social
and personal realities. The world will be different in 1995 than it was
in 1955 and we, ourselves, will be different people in it. Temporal
relocation is no more responsible for changes in a mismatched Italian
couple's prognosis than geographical relocation per se would be responsible
for changes due to shifting the setting from Italy to New York.
The present study asks whether likelihood judgments for past events
differ from those for otherwise similar future events, with all these
sou-ces of confounding undone. Subjects in Past and Future groups were
presented with identical descriptions of events and asked to judge the
likelihood of possible subsequent developments, or "outcomes." For Past
subjects, the evaluated outcomes were set in the past; for Future subjects,
they were set in the future. These events were constructed so that temporal
setting-related changes in meaning were minimal.
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Temporal Setting
5
Formally, deductive Inferences of this type are invariant with regard
to the temporal setting of the outcome judged. Thun, it should make no
difference to the judge whether the fate of a possible outcome (its occurrence
or non-occurvence) has already been decided (past events) or has yet to be
decided (future events)—unless, of course, temporal setting alone affects
his perception.
Two explicit hypotheses were tested: (a) past events are judged to be
more likely than equivalent future events; and (b) oast events are judged
more ex' -emely than equivalent future events. The former might be called
the "likely past" hypothesis, H.. , and the latter, the "extreme past" hypo-
thesis, H . H. refers to an increase in the central tendency of likelihood
judgments for past events; H refers to an increase in the dispersion of
likelihood judgments for past events. They e examined with outcomes
provided both by the experimenter (Experlmenu 1) or by the judge himself
(Experiment 2).
Experiment 1
Method
Design. In order to assess the effect of temporal sercing on judgment,
subjects were asked to evaluate the likelihood of a series of fifteen event
outcomes, each in the light of an accompanying event description. Theae
outcomes were set either in the past or future. The event descriptions were
always set in tue past. One outcome was evaluated for ea^h event description.
A specimen event description is:
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Temporal Setting
8
A French artist, Dollard St. Laurent, recently submitted a claim
to the government patent office. In this claim, he demanded a patent
for his artistic style. St. Laurent Is a well-known figure In
opposition circles.
The corresnondlne Past outcome question was:
In the light of these data, what. In your opinion, are the chances
that he received a patent?
The corresponding Future outcome question was:
In the light of these data, what. In your opinion, are the chances that
he will receive a patent?
In Experiment la, Past-Future differences were minimal, frequently
amounting to no more than a change in a single verb (as in the examples
given). No mention of temporal setting appeared in thr. instructions.
Experiment lb was identical to Experiment la except that the strength of the
manipulation was increased by a change of instructions and by adding details
which included tl;ue-related references. For example, the outcome presented
above was changed from ". . . he (the French artist) received a patent"
to ". . .he received a patent, and his success began a wave of similar
claims for receipt of patents from known and unknown artists alike."
Stimulus construction. The event descriptions dealt with a variety
of reasonably interesting content areas. The adjoining outcomes were
selected to evoke a full range of responses, from very likely to very un-
likely, over tasks. Several additional examples appear in Table 1. Nine
Insert Table 1 about here
of the 15 event descriptions which produced greatest inter-subject agreement within
groups and greatest inter-subject disagreement between groups in Experiment la
were reused.
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Temporal Setting
7
The success of the experimental manipulation depends, of course, on the
independence of temporal setting changes from changes in accompanying social
realities. Among the precautions taken to guarantee this independence
were: (a) specifically setting events and outcomes in the near future or
recent past to eliminate possible differences caused by secular trends, such
as a rising crime rate or increasing sexual freedom; and (b) attempting to
equate the past and future time periods between the event and outcome, in
case probability of occurrence was related to the length of time allotted.
Each event appeared on a separate page. The different events were collated
into booklets with a standard order which varied the likelihood of sequential
outcomes.
Procedure. For each of the two experiments, the test booklets were
distributed to a single class of subjects from a pile in which booklets belonging
to the two conditions alternated. Given the minimal differences between the
versions and the minimum of disturbance during the administration, there is
little reason to believe that subjects were aware of the differences. This
procedure allowed distribution of the booklets to a fairly homogeneous group
of subjects in an unsystematic fashion ensuring fairly equal numbers of
subjects in each experimental condition.
instructions. In Experiment la. where every effort was made to obscure
the temporal setting variably the general instructions were identical for
all conditions. They read. "A number of short descriptions of social and
personal events appear below. Some are factual, others Imaginary. For each
description you will be asked to evaluate the likelihood of a possible outcome
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Temporal Setting
8
In the light of the data. Indicate your answer with an 'X' In the appropriate
space." The twenty-one point response scale was labelled at three points:
20 = greatest possible chances; 10 = medium chances; 0 = least possible
chances. All Instructions and materials were in Hebrew.
For Experiment lb, they were changed to read: "A number of descriptions
of social and/or personal events which recently occurred (are about to terminate—
for Future subjects) appear below. For each description, you will be asked to
evaluate the chances that the event terminated (will terminate) in a particular
fashion."
Subjects. For Experiment la, the subjects were A8 students in an Intro-
ductory Statistics class at the University of the Negev, Beer-Sheba, Israel,
with 24 in each group. For Experiment lb, the subjects were 82 students
in an Intermediate Statistics class at the University of the Negev; 40 were
in the Past group and 42 in the Future group.
Results
H . Two measures used both here and in Experiment 2 are the "overall
media7 response" and the "median median response." The former Is the tLedian
of all responses by all subjects In a condition. The latter Is computed by
finding the median of each individual subjects' 9 or 15 likelihood judgments
and then finding the median of these medians. The median median is free of
the intra-subject dependence found in the overall median (to which each
subject contributed 9 or 15 responses).
The "likely past" hypothesis predicts higher likelihood assignments
to past outcomes. For both experiments, overall medians and median medians
were identically 10 for all conditions. Nor was there any tendency for Past
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Temporal Setting
9
outcomes of individual events to be judged more likely than the corresponding
Future outcomes.
H . The "extreme past" hypothesis predicts the assignment of more e
extreme (i.e., more disperse) likelihood values to Past outcomes. The mean
(absolute) deviation of each subject's responses from his median likelihood
assignment was calculated. The means of these mean deviations appear In
Table 2. Contrary to H , there is no appreciable difference in the dispersion
of Past and Future likelihood responses. Nor were there any consistent
Insert Table 2 about here
differences in the extremity (distance from 1.0) of the medi,--« likelihood
assignments to the Past and Future outcomes of individual events.
Discuaaion
Temporal perspective clearly fails to affect either the central tendency
or the dispersion of likelihood Judgments on the tasks used in Experiments la
and lb. If not completely illusory, the temporal setting effect must be
sought in more restricted and more carefully specified circur.stances. One
aspect of the present task which could have obscured such an effect is the
fact that subjects evaluated outcomes which they themselves had not produced.
Possibly, the act of production, absent in these experiments, elicits or
focuses attention upon critical differences between prediction and postdiction,
while the temporal setting of prepared outcomes is ineffectual. An analogy
with some appeal might be a difference between past (historical) and future
(science) fiction. Production of the two may evoke and require rather different
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Temporal Setting
10
"frames of mind." Once prodaced by others (authors), however, examples of
both genres may be Judged in much the same fashion by readers. Indeed, in
an unpublished study, Condry (Note 2; cited in Toffler, 1970) did find
differences in the length and imaginativeness of past and future outcomes
which pubjects had produced. Tversky and Kahneman (1973) have both hypothesized
and shown that likelihood judgmants may depend upon ease and conditions of
outcome production, with more ivailable outcomes judged more likely. Thus,
any temporal setting effect on production could lead to changes in likelihood
judgments.
Experiment 2 was designed to explore the possibility that outcome pro-
duction is necessary to evoke temporal setting-related differences in judg-
ment.
Experiment 2
Method
Design. For each of several event descriptions, subjects were asked to:
(a) produce a number of possible outcomes, and (b) evaluate the likelihood
of each outcome produced on a scale from 0 to 20. The Past group was asked
to.produce outcomes which may have happened, the Future group to produce
outcomes which possibly will happen. The event descriptions were identical
for both groups.
As little is known about how the conditions under which outcomes are
produced affect the way in which their likelihood is judged, several variations
on this basic design were included. In Experiments 2a and 2b subjects were
instructed to produce as many outcomes as possible; in Experiment 2c to
produce a fixed number of outcomes (four)—in the event that there were
effects which only emerge or vanish when subjects have exhausted their
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Temporal Setting
11
imaginations for possible outcomes. Experiments 2a and 2b differed in the
number of possible cutcomes which subjects could have produced, considering
the nature of the event in question. In Experiment 2a, this number was
extremely large (i.e., very many things could happen), whereas In Experiment
2b no more than ten or twelve outcomes were possible. It was thought that
the size of the set of possible outcomes might affect subjects' outcome
production and evaluation proeesses.
Each event appeared on a separate page. For Experiments 2a and 2b,
there were 12 numbered spaces for inserting and evaluating outcomes, along
with unnumbered space for an additional five or six outcomes. Following
the Instructions was a sample problem for which two possible outcomes were
affixed (In the proper tense) with likelihood estimates obtained from an
informal poll of ten students. The order of the events was randomized in
test booklets.
Stimulus construction. One of the event descriptions used in Experiment
2a was:
A well-known sculptor returned to his studio following a short vacation
and found that his former wife had burst into his studio during his
absence and destroyed statues which constituted all of his work for a
period of more than a year.
The second event was a Hebrew adaptation of that used by Condry (Note 2)
and concerned parents'handling a problem confronted by their adopted daughter;
the third appeared In Experiment 1 and dealt with a family crisis. Two
examples of the event descriptions used in Experiments 2b and 2c appear
in Table 1.
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lemporal Setting
12
The events used in Experiment 2b also appeared in Experiment 2c. In
Experiments 2a and 2b subjects responded to three different event des-
criptions, in Experiment 2c to seven. Each spent approximately a half an
hour at the task.
Procedure. Same as Experiment 1.
Subjects. Sixty undergraduates in an Introductory Psychology class at
the Hebrew University of Jerusalem participated in Experiment 2a; 27 were
in the Future group, 33 in the Past group. Eighty-nine Introductory
Psychology students at the Hebrew University of Jerusalem participated in
Experiment 2b; 42 were in the Past condition, 47 in the Future. Forty-six
students in an Introductory Methodology class at the University of the Negev
participated in Experiment 2. They were equally divided be .ween the two
conditions.
Results
Power of manipulation. In Experiment 1 it was impossible to ascertain
whether subjects had actually attended to the temporal setting of the outcomes
they judged. The present design, however, affords a simple and effective
test: noting the tense of the verbs appearing in the outcomes produced.
Table 3 shows the proportion of subjects who used the wrong tense in each
condition. For each experiment, although most subjects did respond properly
Insert Table 3 about here
to the temporal setting instructions, there was a clear tendency to transform
poatdictive into predictive tasks (i.e., to use the future tense for possible
past outcomes). In each case, wrong tense responses were randomly distributed
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Temporal Setting
13
over 8ub|ects, indicating that they were not produced by any subset of subjects
who "missed" the instructions but by a large number of subjects who tended
to "lapse" into prediction when .^ostdiction was required.
Rp Experiment 2a produced uome slim support for H . The overall
medians for Past and Future, respectively, were 12 and 10, 14 and 10, and
15 and 10, for the three events, ihe corresponding median medians for Past
and Future subjects were 12 and 10, 12 1/2 and 12, and 14 and 10. Thus,
in each case. Past outcomes were on the whole more likely than Future
outcomes. For the third event, this difference was significant (x2(l) = 7.38;
p < .01; median -est).
This support vanished in the remaining experiments. For both Experiments
2b and 2c, the overall medians and medians medians were essentially indistinguish-
able on the bcsis of temporal setting.
He. He predicts greater dispersion for past outcomes, indicating Past
subjects' greater confidence in their ability to distinguish degrees of
likelihood in the outcomes which they have produced. The most relevant
measure of the dispersion of subjects' likelihood judgnents is the mean
(absolute) deviation of individual subjects' likelihood judgments for the
various outcomes he had produced for each event. The means of individual
subjects' mean within-event dispersion appears in Table 4. As can be readily
seen, there are no consistent differences. Within-event dispersion was
Insert Table 4 about here
slightly larger for Past than for Future subjects in Experiment 2a, and
slightly smaller in Experiments 2b and 2c. None of these differences are
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1 empora] Setting
14
significant. Combining these results as suggested by Winer (1962, p. 44) k
yields z = -.65 ( -E t./Jk ; where k. •= number of groups), also Insignificant. 1-1
In no case does restricting attention to those events which had the
largest proportion of correct tense responses, restricting attention to correct
tense responses or treating future tense responses of Past subjects as having
been produced by Future subjects, and vice versa, provides any additional
support for either H, or H . 1 e
Effect of production. A number of analyses showed the Judged livelihood of
outcomes to depend upon the conditions under which they were produced. For
example, the later an outcome is produced, the less likely it is judged,
(the rank order correlations between likelihood and position of production
for individual subjects had a mean of -.26 over groups). The same relation-
ship was found within categories of similar outcomes produced by different
subjects (see below). Subjects who produced any given outcome earlier tended
to find it more likely (mean rank order correlation over outcome categories ■
-.17). In addition, the more outcomes subjects produced, the lower the median
of their likelihood judgments (mean rank order correlation between number
of outcomes produced and median likelihood judgment = w.27). The latter
relation suggests a possible artifactual source of the small Past-Future
difference which emerged in Experiment 2a. Future subjects might have assigned
lower probabilities as a result of having produced mbre outcomes. This is
not, howevrr, the case, as Future subjects actually produced slightly fewer
outcomes in both experiments where they were asked to produce as many outcomes
as possible (2a and 2b).
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Temporal Setting
15
Outcome content. Outcomes were categorized according to content in
order to obtain further insight into Papt-Future differences. Two questions
asked were: (a) Do Past and Future subjects evaluate the likelihood of
similar outcomes similarly? an-l (b) Do Past and Future subjects tend to
produce different outcomes? The answer to the first question ..is a solid
"no," to the second a tentative "yes."
Regarding question (a), for the event in the example above, there was a
marked tendency for the medians of corresponding outcome categories to be
more likely and more extreme for Past than for Future groups. There were,
however, no systematic differences for the remaining two events of Experiment
2a, nor for the events of Experiments 2b and 2c. Regarding question (b),
the distributions of Past and Future responses over the outcome categories
were compared by chi-square tests following elimination of very small categories.
The two distributions were significantly different (p < .001) for all three
events In Experiment 2a, for one of the three in Experiment 2b, and for four
of the seven in Experiment 2c. Impressionistic analysis of these differences
indicated that t'ast outcomes tended to be more complex and imaginative than
Future outcomes.
Discussion
Contrary to the sure past hypothesis, there is no consistent evidence
that temporal setting affects either the central tendency (H.) or the
dispersion Oy of likelihood judgments, either for subject- or experlmenter-
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Temporal Setting
16
produced outcomes, for any of the varied events and tasks used here. The weak
effects obtained in Experiment 2a must, then, be considered a chance result in
light of the mass of contradictory evidence.
There is, however, evidence that temporal setting does affect the pro-
duction of possible outcomes—as reflected in: (a) the tendency to transform
postdictive tasks to predictive (i.e., the production of future tense Past
outcomes); and (b) the differing distributions of Past and Future outcomes
over categories for eight of the 13 events used. Temporal setting did not,
however, affect the number of outcomes which subjects were capable of
producing (Experiments 2a and ?b).
Aside from the evidence they provide on the effect of temporal setting
on likelihood judgments, these results provide some general insight
into how people perform such judgments. Tversky and Kahneman (1974) have
suggested two heuristics which judges might use in likelihood estimation
tasks like those used here; "availability" and "representativeness." The
availability-guided Judge deems an outcome likely according to the ease
with which it is produced or imagined. The representativeness-guided judge
evaluates the likelihood of an outcome by the degree to which it appears to
be a natural outgrowth of the situation described.
The fact that temporal setting affects outcome production without
affecting likelihood Judgments suggests that these likelihood judgements
rely on representativeness rather than availability—which should
be sensitive to changes in production. It is, in turn, highly plausible
that representativeness-guided judgment would be insensitive to temporal
setting. Not only is there no obvious way in which temporal setting would
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Temporal Setting
17
change the perceived evenc description-possible outcome fit, but it has
been found that reliance on npresentativeness obscures such selient and
normatively important aspects of event descriptions as sample size and
base-rate probabilities (Kahr.eman & Tversky, 1972, 1973),
What remains to ba explained is why some people believe in the ''sure
past" hypothesis. The simplest explanation is that pastness is confused
with its ecological correlates, concomitants which do, in fact, generally
lead to greater judgmental confidence. One correlate of temporal setting
which may contribute to a "sure past" illusion is contemporaneous changes
xn social realities. If human behavior is perceived to have been more
predictable and stable in the past than it will be in the future (another
claim advanced by Toffler), then pastness might well be misidentified as
allowing Judgmental sureness.
A second, possibly more significant, correlate of temporal setting
is outcome knowledge. Judges looking at the past typically know "how it
turned out." With this additional knowledge, and the hindsight it confers.
Judges are able to see and show the relative "inevitability" of past
events (Carr, 1961; Flschhoff, 1974; Fischhoff & Beyth, 1975; Nowell-Smith,
1970). Outcome knowledge seems to enable people to impose upon the past a
degree of certainty which they would not aare to imposa upon the future.
The relative prevalence of outcome knowledge for past events may create
the mistaken Impression that pastness alone is a sufficient condition
for uncertainty Judgment. Past and Future subjects here, however, were
equally Ignorant of the outcomes of the events they Judged.
A third variable related to temporal setting may be degree of control.
One can do something about the future, but very little about the past.
Virtually all of the literature concerning perception of past and future
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Temporal Setting
18
events (Dcob, 1970) deals with events In the Judges' personal rjaet or future.
Such personal Involvement may give the future a feeling of openness or con-
trollability which rnduces Judgmental confidence as it encourages phenomena
like "magical thinking" (Rothbart & Snyde., 1970). Again it would not be
pastn^ss, but a correlate which produces greater confidence.
In conclusion, it may be worthwhile to consider the general paradigm
which underlay the p.resent studies and which seems to offer possibilities
for fruitful interaction between psychology and other disciplines. A
common sense observation routinely put forth and used by a number of scientists
and Bhilosophers of science has provided the Impetus for investigation of a
systemir variable of general psychological interest. Empirical analysis
has, in turn, shown the inaccuracy of these anecdotal observations and
suggested needed refinements. It had also been found, anecdotal reports
to ':he contrary, that the temporal setting of events is a variable which
does not have to be considered in the design and comparison of judgmental
studies.
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1.
2.
Temporal Setting
19
Reference Notes
Kissinger, H. Opening speech at the Geneva convention, December, 1973.
Condry, J, Personal communication, October 3, 1973.
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Temporal Setting
20
References
Ayer, Ä. J. The problem of knowledge. London: MacMillan, 1956.
Bortner, R. W., & Hultsch, D. F. Personal time perspective in adulthood.
Developmental Psychology, 1972, 7, 98-10:.
Bratfisch, 0., Ekman, G., Lundberg. U., & Kruger, K. Subjective temporal
distance and emotional involvement. Scandinavia Journal of Psychology,
1971, 12, 147-160.
Carr, C. E. What is history? Hammondsworth: Penguin, 1961.
Cohen, J. Psychological time in health and disease. Springfield, 111.:
Thomas, 1967.
Danto, A. Analytic philosophy of history. Linden: Oxford, 1965.
DeJouvenal, B. The art of conlecture. New York: Basic Books, 1967.
Doob, L. The patterning of time. New Haven: Yale, 1970.
Ekman, G., & Lundberg, U. Emotional reaction to past and future events
as a function of temporal distance. Acta Psychologica, 1971, 35, 430-441.
Fischhoff, B. Hindsight and foresight: The effects of outcome knowledge
on judgmer-- under uncertainty. Oregon Research Institute Research Bulletin.
1974, 14, No. 14.
Tischhoff, B., & Beyth, R. I knew it would happen—remembered probabilities
of once-future things. Organizational Behavior and Human Performance,
1975, in press.
Kahnet.an, D., & Tversky, A. Subjective probability: A judgment of repre-
sentativeness. Cognitive Psychology, 1972, 2» 430-454.
Kahneman, D. , & Tversky, A. On the psychology of prediction. Psychological
Review. 1973, 80,237-251.
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PlW^^jllW^^JiJ^IM-ll^lPMIIllUW. jpj^WjJW.JilllP^PPpW'! mmmmmismmmjm'm ■ppppipww
l.^.-,.-. :..L ._,,,
Temporal Setting
21
Korlat A., & Fischhoff, B. "What day is today?" An Investigation of the
process of temporal orientation. Memory and Cognition. 1974.. 2, 201-205.
Nowell-Smith, P. Historical explanation. In H. Kiefer & K. Munltz (Eds.).
Mind, science, and history. Albany: State University of New York Press,
1970.
Poiak» F- Prognostics. Amsterdam: Elsevier, 1965.
Rothbart, M., i, Snyder, M. Confidence in the prediction and ppstdiction
of an uncertain event. Canadian Journal of Behavioral Science. 1970,
2, 38-43.
Seignobos, C, & Langlois, C. Introduction to the study of history. New
York: Holt, 1898.
Toffler, A. Future shook. New York: Random House, 1970.
Tversky, A., & Kahneman, D. Availability: A heuristic for Judging frequency
and probability. Cognitive Psychology. 1973, 5, 207-232.
Tversky, A., & Kahneman, D. Judgment under uncertainty: Heuristics and
biases. Science. 1974, 185, 1124-1131.
Winer* B- J- Statistical principles in exEerimgntaj design New York:
McGraw-Hill, 1962.
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npünp mvimimmmmmmmmmm muMmmimiimmm, mmM^mm.-Mwmmmwm.,'-'j'.*&^*mmmfi*i'^
Temporal Setting
22
Footnotes
This study was supported by the Advanced Research Projects Agency
of the Department of Defense (ARPA Order No. 2449) and was monitored by
ONR under Contract No. N00014-73-C-0438 (NR 197-026). The research reported
constituted a portion of a doctoral dissertation submitted to the Hebrew
University of Jerusalem, May, 1974. Consultation with Amos Tversky, Paul
Slovic, and Sarah Lichtenstein contributed substantially to this research
and is gratefully acknowledged. Reprint requests may be sent to the author
at Oregon Research Institute, P. 0. Box 3196, Eugene, Oregon 97403.
A third group which received future outcomes (as above) with future
event descriptions (e.g., "A French artist is about to submit a claim . . .")
was also included in this study. It allowed evaluation of the effects of
changing the temporal setting of the event description as well as the
outcome. Results for this group are not reported in detail here as it was
eliminated from further experiments because of subjects' reported discomfort
with future tense f^vent descriptions. Responses to these items were in-
distinguishable from responses to the corresponding Past and Future Items.
2 Additional evidence of the dependence of likelihood judgments on
aspects of outcome production emerged in Experiments 2b and 2c below. It
is omitted for the sake of brevity here, but is available upon request.
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Table 2
Mean Between-Event Dispersion
Experiment
la lb
Condition Past
Future
3.18
3.57
4.76
4.57
t
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Temporal Setting
25
Negative sign for t test for difference indicates
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Temporal Setting
26
Table 3
Tenses of Outcomes Produced
Tense Required (condition)
Experiment 2a Experiment 2b Experiment 2c
Past Future Past Future Past Future
Past 92.9% 0% 78% 4% 89.9% 9.2%
Future 7.1% 100% 22'* 96% 10.1% 90.3%
a z 1.96 3.97 0.66
aThe difference In the proportion of subjects using the wrong tense
In each condition.
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