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ARI Research Note 87-43

EFFECTS OF STRESS ON JUDGEMENT AND DECISION MAKING IN DYNAMIC TASKS

Kenneth R. Hammond

University of Colorado

(V~ for

00 Contracting Officer's Representative

00 Judith Orasanu

Islas I

BASIC RESEARCH LABORATORY

Michael Kaplan, Director

DTIC _ _ LECTE0 NOV 2 4 1987D

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U. S. Army

Research Institute for the Behavioral and Social Sciences

October 1987

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Technical review by toyJustif~ication

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to comply with regulator requirements. 1t ho% been given no Primary distribution other than to OTIC be availablie only through OTIC of Other reference services such as the National Technical information Service (NTIS. The victis. cPiniens. and/or findings contained in this rispon are those of the author Wi en'd should not be consitue as an ofcia, Cipaiment of the Army position. policy. or decision. unless so designated by other official documentation.
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I. REPORT NUMBER 12. GOVT ACCESSION NO 3. RECIPIENT'S CATALOG NUMBER

ARI RESEARCH NOTE 87-43

4. TITLE (.mdSubte) S. TYPE OF REPORTA PERIOD COVERED

Effects of Stress on Judgement and Interim Report

Decision Making in Dynamic Tasks September 86 - August 87

6. PERFORMING ORG. REPORT NUMBER

7. AUTHOR(&) S. CONTRACT OR GRANT NUMBER(*)

Kenneth R. Hammond MDA903-86-C-0142

9. PERFORMING ORGANIZATION NAME AND ADDRESS 10. PROGRAM ELEMENT, PROJECT. TASK

Center for Research on Judgement and Policy AREA & WORK UNIT NUMBERS

Campus Box 344, University of Colorado 2QlllO2B74F

Boulder, CO 80309-0344

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U.S. Army Research Institute for the Behavioral October 1987

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19. KEY WORDS (Continue on revere side it necee ry and Identify by block number)

Judgement Uncertainty, 1A(Arb ,if4 .

Experts Dynamic Task)

06Cognition) Problem Solving)

21LAuSTRACT fVindowe an eveno @gg N noewesy md lgewnty by block nuabet)

>. Expert weather forecasters were observed as they attempted to forecast hail,

microbursts, and severe storms. Studies of judgement policies were also conducted with representations of storms. Modest agreement among forecasters was

found in all three cases, but hail forecasts were found to be of low accuracy.

Judgement models, an AI expert system, and seven forecasters showed about the

same degree of accuracy. Current psychological theory concerning judgement and

decision making was found to be insufficient for these circumstances. L,.,<1./.,

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TABLE OF CONTENTS

Goals.............................................................1I

Initial Plan of Work................................................ 1

Current Efforts.................................................... 1

tMicroburst Forecasting............................................ 2

Field observations.............................................. 2

Laboratory-type studies ......................................... 2

H al............................................................ 3

Severe Weather ................................................... 3

Theoretical and Conceptual Work...................................... 4

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EFFECTS OF STRESS ON JUDGMENT AND DECISION MAKING IN DYNAMIC TASKS

I September 1986 - 31 August 1987)

Kenneth R. Hammond (University of Colorado, Boulder), Principal Investigator

EXECUTIVE SUMMARY

Goals

The principal goals of this research project are to: (a) discover the

nature of judgment and decision making in dynamic tasks; (b) study the effects

of stress on judgment and decision making TVisuch1 tasks. Neither project has

bee-nundertaken previously by researchers in this field.

Initial Plan of Work

We had intended to (a) study college sophomores and others in laboratory

situations (Year I), (b) move to the study of professional experts in dynamic

tasks (Year II) and (c) study experts under stress in dynamic tasks (Year

III). This plan was changed midway in the first year when it became apparent

that we would have an excellent--and rare--opportunity to move directly to the

situation planned for Year II; that is, to the study of weather forecasters

coping with dynamic tasks (forecasting microbursts, hail, and severe weather)

with a clear possibility of working with these same experts (and same tasks)

under stressful conditions, thus providing continuity in moving us directly

toward our principal goals. Because of the recognition of the importance of

research of this sort, the Center for Atmospheric Research (NCAR) and the

National Oceanic and Atmospheric Administration (NOAA) not only offered us the

cooperation of their expert forecasters, but offered supplemental funding for

the ARI project. As a result we were able to employ additional staff members

(an expert Ph.D. level judgment researcher and a research assistant). As our

Quarterly Reports have indicated, we moved quickly to take advantage of these

unusual circumstances and midway in the first year began work planned to begin

in Year II, that is, direct study of experts coping with dynamic tasks.

Current Efforts

We have undertaken three projects (the study of meteorologists' efforts

to forecast microbursts, hail, and severe weather). Each is described in

turn.
J/DM in Dynamic Tasks

Hammond

Microburst Forecasting

The invitation to participate in this project (sponsored by the Federal

Aviation Administration) offers the unusual opportunity to study experts who

are attempting to (a) understand a type of dynamic environmental activity

(weather phenomena of critical importance to air travel) and (b) forecast its

occurrence. Moreover, the meteorologists who are undertaking thi's work are

provided with the most sophisticated state-of-the-art information gathering

and display devices available (e.g., Doppler radar), thus providing us with

laboratory conditions ordinarily unimaginable. And because of the full

cooperation of the project manager and staff meteorologists, we have been able

to make field observations as well as laboratory-type studies of these

experts' efforts to understand and predict the behavior of complex dynamic

systems. Each effort is described in turn.

Field observations. During these observations we acquainted ourselves

with the complicated computer hardware and software available to the

meteorologists, and observed the meteorologists' activities under real time

conditions. These observations led us to the conclusion that several sources

of information and several display modes are available to the meteorologists.

In these conditions, the meteorologists (a) are active seekers of information

that changes over time, (b) are active hypothesis generators about what has

happened, is happening, and will happen, (c) employ both deductive and

inductive inferences, (d) rely partially on scientific principles and

partially on empirical regularities and thus employ both functional analyses

and pattern matching strategies, and (e) make judgments and decisions about

dynamic environmental events under considerable uncertainty that is created by

incomplete and imprecise data, and incomplete physical, chemical, and

climatological principles. In our view, this situation is far from those

ordinarily studied in laboratory situations by psychologists, but highly

representative of the vast majority of conditions under which judgments and

decisions, military and otherwise, are made. This situation, therefore, is

ideal for the present research project. We also concluded that our studies

must follow from a new and much more complex psychological theory of judgment

and decision making than has thus far been advanced by anyone.

Laboratory-type studies. Our first steps were to discover to what extent

the experts would exhiblt inter- and intra-observer agreement with regard to

the forecasting of microbursts when given (a) perfectly reliable measurements

of weather data (assumption that observers of the radar screen and other

instruments should show perfect inter- and intra-observer agreement) and (b)

perfectly reliable (as observed) interpretations of those data, as for

example, interpreting the wind velocities to signify such microburst

precursors as "descending core, collapsing storm, etc. Only modest agreement

among the experts was found. This result (including the finding that one

meterologist's judgments were far different from the others) was new

information to the forecasters. We then investigated the question of whether

2
J/DM in Dynamic Tasks

Hammond

the forecasters could translate profile information about storms (as described

above) into mental images of the storms, and to what extent the storm images

would be similar across forecasters. Although it was found that the

forecasters could easily draw schematic diagrams of storms depicted in the

profiles, only modest agreement among the forecasters was found with regard to

the similarlity of storm images. And when asked to transform their storm

images back into profiles only a rough translation appeared possible (though

analysis is continuing on this question). A Technical Report on the above

project is in preparation.

Hail

This project differs from the microburst project in that actual data

including a criterion for evaluating the accuracy of forecasters were

available. Cue data (from Doppler radar scans of thunderstorms) and criterion

data (observation of hail by chase teams on the ground) were provided by NOAA

for 453 cases. Since an expert system for hail prediction has been developed

by NOAA, it was possible to set up a competition among forecasters' forecasts,

the AI expert system's forecasts, and-forecasts based on judgment models of

the forecasters. It was found that the three methods of forecasting produced

roughly the same accuracy (rather low, because of the inherent uncertainty in

predicting hail from the available data). The judgment model, however, is by

far the least costly and simplest to employ, and thus the most efficient. We

know of only one previous study that made such comparisons; similar results

were found. Work on this project continues. The analysis of the data are

nearly complete and a Technical Report on this project is in preparation.

Severe Weather

This study examines weather forecasters' judgments in a dynamic task of

critical importance. NOAA provided access to an advanced interactive computer

graphics weather forecasting workstation for this experiment, thus providing

us with a laboratory of great complexity and representations. Real weather

data were replayed in simulated forecasting sessions. Three forecasters,

working individually, were asked to think aloud as they decided when and where

to issue warnings and alerts for thunderstorms. Their deliberations were tape

recorded and a record was kept of their concurrent actions. Comparison of

severe weather warnings and alerts issued by different forecasters for the

same day indicate that forecasters generally focus on the same storms (of the

several apparent), but the actions taken with regard to those storms vary

substantially among forecasters. Transcripts of the forecasters' verbal

descriptions of their forecasting strategies are being analyzed. They suggest

that differences among forecasters are due to differences in (a) selection of

information, (b) strategies for integrating information, (c) implicit criteria

or thresholds for issuing warnings or alerts. A Technical Report on this

project is in preparation.

3
J/DM in Dynamic Tasks

Hammond

Theoretical and Conceptual Work

Our study of weather forecasters making judgments in dynamic tasks under

actual conditions where instrumentation of considerable complexity is used has

led to a definite conclusion about present theory in judgment and decision

research, namely, it is far too simple to be of use in dynamic tasks of any reasonable complexity. Therefore we are developing a general theory to

account for the cognitive activity of these experts under these complex

conditions. A Technical Report is in preparation.

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