Table Of ContentEXPERIMENTAL
SLIPS AND
HUMAN ERROR
Exploring the Architecture of Volition
COGNITION AND LANGUAGE
A Series in Psycholinguistics • Series Editor: R. W. RIEBER
Recent Volumes in this Series
THE COLLECTED WORKS OF L. S. VYGOTSKY
Volume 1: Problems of General Psychology
Volume 2: The Fundamentals of Defectology (Abnormal Psychology and
Learning Disabilities)
Edited by Robert W. Rieber and Aaron S. Carton
DEVELOPMENTAL PSYCHOLINGUISTICS: Three Ways of Looking at a
Child's Narrative
Carole Peterson and Allyssa McCabe
THE DISCURSIVE SOCIAL PSYCHOLOGY OF EVIDENCE
Symbolic Construction of Reality
Salomon Rettig
EXPERIMENTAL SLIPS AND HUMAN ERROR: Exploring the Architecture of
Volition
Edited by Bernard J. Baars
LANGUAGE AND COGNITION: Essays in Honor of Arthur J. Bronstein
Edited by Lawrence J. Raphael, Carolyn B. Raphael, and Miriam B. Valdovinos
MEANING AND CONTEXT: An Introduction to the Psychology of Language
Hans Hormann
Edited and with an introduction by Robert E. Innis
UNDERSTANDING MEXICANS AND AMERICANS: Cultural Perspectives in
Conflict
Rogelio Diaz-Guerrero and Lorand B. Szalay
THE USE OF WORDS IN CONTEXT: The Vocabulary of College Students
John W. Black, Cleavonne S. Stratton, Alan C. Nichols,
and Marian Ausherman Chavez
VYGOTSKY'S SOCIOHISTORICAL PSYCHOLOGY
AND ITS CONTEMPORARY APPLICATIONS
Carl Ratner
A Continuation Order Plan is available for this series. A continuation order will bring delivery of each
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EXPERIMENTAL
SLIPS AND
HUMAN ERROR
Exploring the Architecture of Volition
Edited by
BERNARDJ. BAARS
The Wright Institute
Berkeley, California
Springer Science+Business Media, LLC
Library of Congress Cataloging-in-Publication Data
Experimental slips and human error : exploring the architecture of
volition / edited by Bernard J. Baars.
p. cm. — (Cognition and language)
Includes Indexes.
ISBN 978-1-4899-1166-7
1. Speech errors. 2. Will. 3. Psychology, Experimental.
I. Baars, Bernard J. I I. Series.
P37.5.S67E97 1992
401'.9—dc20 92-23100
CIP
ISBN 978-1-4899-1166-7 ISBN 978-1-4899-1164-3 (eBook)
DOI 10.1007/978-1-4899-1164-3
© Springer Science+Business Media New York 1992
Originally Published by Plenum Press, New York in 1992
Softcover reprint of the hardcover 1st edition 1992
All rights reserved
No part of this book may be reproduced, stored in a retrieval system, or transmitted, in
any form or by any means, electronic, mechanical, photocopying, microfilming, recording,
or otherwise, without written permission from the Publisher
Contributors
BERNARD J. BAARS, The Wright Institute, 2728 Durant Avenue, Berkeley, Cal
ifornia 94704.
JACK W. BERRY, The Wright Institute, 2728 Durant Avenue, Berkeley, Cali
fornia 94704.
LAWRENCE BIRNBAUM, The Institute for the Learning Sciences, Northwestern
University, Evanston, Illinois 60201.
GORDON H. BOWER, Department of Psychology, Stanford University, Stanford,
California 94305-2130.
JENN-YEU CHEN, Department of Child Psychiatry, New York State Psychiatric
Institute, New York, New York 10032.
JONATHAN COHEN, Department of Psychology, Carnegie-Mellon University,
Pittsburgh, Pennsylvania 15213.
GREGG COLLINS, The Institute for the Learning Sciences, Northwestern Uni
versity, Evanston, Illinois 60201.
GARY S. DELL, Department of Psychology, University of Illinois at Cham
paign, Champaign, Illinois 61820.
DONALD G. MACKAy, Department of Psychology, University of California at
Los Angeles, California 90024.
MARK E. MATTSON, Social Sciences Division LL916, Fordham University, New
York, New York 10023.
v
vi Contributors
DONALD A. NORMAN, Department of Cognitive Science, University of Califor
nia at San Diego, La Jolla, California 92093.
JAMES T. REASON, Department of Psychology, University of Manchester, Man
chester, M13 9PL, United Kingdom.
RENEE J. REPKA, Department of Psychology, University of Rochester, Roches
ter, New York 14627.
ABIGAIL J. SELLEN, MRC Applied Psychology Unit, 15 Chaucer Road, Cam
bridge CB2 2EF, United Kingdom and Rank Xerox Ltd. Cambridge Euro
PARC, 61 Regent Street, Cambridge, CB2 lAB, United Kingdom.
JOSEPH PAUL STEMBERGER, Department of Communication Disorders, Uni
versity of Minnesota, Minneapolis, Minnesota 55455.
Preface
Whereas most humans spend their time trying to get things right, psycholo
gists are perversely dedicated to error. Errors are extensively used to in
vestigate perception, memory, and performance; some clinicians study errors
like tea leaves for clues to unconscious motives; and this volume presents the
work of researchers who, in an excess of perversity, actually cause people to
make predictable errors in speech and action.
Some reasons for this oddity are clear. Errors seem to stand at the nexus of
many deep-psychological questions. The very concept of error presupposes a
goal or criterion by comparison to which an error is an error; and goals bring in
the foundation issues of control, motivation, and volition (Baars, 1987, 1988;
Wiener, 1961). Errors serve to measure the quality of performance in learning,
in expert knowledge, and in brain damage and other dysfunctional states; and
by surprising us, they often call attention to phenomena we might otherwise
take for granted. Errors also seem to reveal the "natural joints" in perception,
language, memory, and problem solving-revealing units that may otherwise
be invisible (e.g., MacKay, 1981; Miller, 1956; Newell & Simon, 1972; Treisman
& Gelade, 1980). Thus errors show how the nervous system copes with failures
of its own goals and constraints; they clearly reveal the limits of our immediate
memory and conscious capacity, but they also show the price to be paid for the
many unconscious automatisms that come to the fore when people are absent
minded or distracted (Reason, 1982, 1983, 1984, 1992). In the world outside the
laboratory, human error is thought to be a major contributor to industrial
disasters, airplane crashes, medical malpractice, and automobile accidents.
And even in the psychology clinic, dysfunctional symptoms appear as persis
tent, unwanted errors in the actions, thoughts, and perceptions of clinical pa
tients (see Baars, 1988, and Chapter 1, this volume; also Spitzer, 1979).
These points are especially applicable to inadvertent errors, or slips,
which are generally defined as errors that violate their own governing inten
tions. Such errors are known to be errors by the person who commits them, but
they are made nonetheless. Slips differ from errors made out of ignorance or
vii
viii Preface
forgetfulness of a goal; they are especially revealing of the control problems we
encounter in carryng out our voluntary intentions.
SLIPS IN MODELS OF LANGUAGE
It may seem obvious that an adequate theory of language should explain
speech errors as well as fluent, correct speech. But this view is not universally
held. For example, Chomsky's widely accepted goal for linguistic theory (1957,
1965) is to generate "all and only the grammatical strings" of a natural lan
guage like English. This definition excludes errors. It has taken some time and
effort to persuade modem linguists that nongrammatical utterances are worth
studying (Fromkin, 1968, 1973). Even today few proposals in the Chomsky
tradition venture to account for errors (but see Fay, 1980; also Chen & Baars,
Chapter 9, this volume).
Likewise, some artificial-intelligence language simulations do quite a
good job of analyzing and generating meaningful sentences, but they do not
make humanlike errors (e.g., Winograd, 1972). Of course one could always add
an error-generating mechanism to these models, but that would be artificial
and unparsimonious. To simulate real human speech, a model should produce
both correct and erroneous output in a natural way, without extraneous theo
retical baggage.
A third type of theory has begun to fill this gap. Parallel distributed
processors (PDPs) treat the cognitive system as a society of specialized net
works, in which activation can spread from node to node in a parallel-inter
active fashion. Dell (1985, 1986) has developed a model of sentence production
in which several levels of representation exist, including phonemic and lexical.
Activation numbers are assigned to lexical and phonemic nodes, and the acti
vation spreads to adjacent nodes both within and between levels. (In "true"
PDP models, connections between the nodes are also assigned strength levels,
a very important theoretical modification.) When simulations are run with a
range of plausible parameters, it appears that this type of network generates
correct lexical output as well as spoonerisms and displacements of single
phonemes. The model demonstrates the same preference for lexical over non
sense spoonerisms that has been shown to exist in both induced and sponta
neous slips (Baars, Motley, & MacKay, 1975; Dell, 1986). Along similar lines,
MacKay (1982, 1987) has proposed a spreading-activation model of the serial
order issue in speech and action. The general properties of PDPs have been
worked out in considerable detail by Grossberg, Rumelhart, McClelland, and
others, and the PDP approach has been used quite successfully to model other
well-studied phenomena in perception, memory, language learning, and action
control (Grossberg, 1982; Hinton & Anderson, 1981; Rumelhart, McClelland,
& the PDP Group, 1986; see also Arbib, 1980; Baars, 1980a,b, 1983, 1987, 1988;
Gel'fand, Gurfinkel, Fomin, & Tsetlin, 1971; Greene, 1972).
Distributed models suggest a new way of thinking about human beings.
We normally think of ourselves as guided by an executive "self': ''we'' have
Preface ix
control over our actions. But distributed systems are strongly decentralized.
The intelligence of such systems resides in its independent components and in
the interactions between them, so that the whole system behaves much like a
market economy, in which thousands of individual transactions take place
without centralized intervention, and fundamentals like supply, demand, and
price emerge from the system as a whole. Details of processing are generally
handled by specialized networks in the processing "society." A decentralized
system does not rule out executive control, just as the existence of market
forces does not rule out a role for government. But it limits the purview of
executive systems and creates possibilities for a reciprocal flow of control
between executive and subordinate elements. Such systems have some distinct
virtues (e.g., Greene, 1972).
Thus, there has been notable progress in understanding and modeling
both correct and erroneous language. However, almost no current theory at
tempts to explain the involuntary character of slips, an issue that is explored
in some detail in Chapters 1 and 4. Indeed, it is argued in Chapter 1 that ''local''
theories of speech and action are in principle unable to explain some of the core
issues raised by slip phenomena, such as the clear psychological differences
between voluntary and involuntary acts (viz. Baars, 1988, and Chapter 4, this
volume).
PRACTICAL ASPECTS OF SLIPS
While the study of slips is contributing to scientific theory, it also has
important practical implications. Inadvertent errors can apparently cause se
rious accidents. Reason (1984, 1992) has analyzed several catastrophic acci
dents in which fatalities were apparently caused by slips: a London bus driver
who crashed a double-decker bus into a low overpass, killing 6 passengers
(perhaps because he was in the habit of driving the same route in a single
decker bus); a train collision killing 90 people because the driver made a
habitual turn, but this time onto the wrong track; and the notorious runway
collision on the island of Tenerife in 1977, in which a KLM Boeing 747 taxied
into the path of a landing jumbo jet, killing 577 passengers and crew. The very
senior KLM pilot failed to obtain clearance from the control tower before
takeoff, perhaps because he had just finished a different assignment involving
hundreds of hours of training pilots in a cockpit simulator, in which runway
clearance was not required. In all three cases, Reason suggests that the fatal
errors may reflect a ''habit intrusion," that is, an inadvertent substitution of a
highly habitual and automatic action for the correct one (see also Langer,
1989).
A similar pattern of accidents may have occurred in flight training with
the B-29 bomber in World War II. The B-29 was a four-engine aircraft designed
to fly on only one engine in an emergency. As a routine part of flight instruc
tion, three of the four engines were shut off in midflight, to prove to student
pilots that the aircraft would indeed continue to fly on just a single engine. For
