Experiments with Drugs. Studies in the Relation between Personality, Learning Theory and Drug Action

413 Pages·1963·7.326 MB·English

by  H. J. Eysenck (Eds.)

EXPERIMENTS
WITH DRUGS
Studies in the relation between Personality,
Learning Theory and Drug Action
Edited by
H. J. EYSENCK, Ph. D.
PROFESSOR OF PSYCHOLOGY, UNIVERSITY OF LONDON
DIRECTOR, PSYCHOLOGICAL LABORATORIES,
INSTITUTE OF PSYCHIATRY
PSYCHOLOGIST,
MAUDSLEY AND BETHLEM ROYAL HOSPITALS
PERGAMON PRESS
OXFORD «LONDON · NEW YORK- PARIS
1963
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Copyright © 1963
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Library of Congress Card No. 61-11548
Set in Times New Roman 10/12 pt and
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LIST OF CONTRIBUTORS
S. AffiA, Ph. D., R. N. GOOCH, M. D.,
M. CHOPPY, Ph. D., R. N. HERRINGTON, M. D.>
G. S. CLARIDGE, Ph. D., H. C. HOLLAND, Ph. D.,
C. G. COSTELLO, Ph. D., J. B. LURIA, M. A.,
J. EASTERBROOK, B. SC, R. LYNN, Ph. D.,
H. J. EYSENCK, Ph. D., E. RODNIGHT, Ph. D.,
B. N. GOMEZ, M. A., J. SYLVESTER, M. A.,
ACKNOWLEDGEMENTS
THIS book would not have been written, nor the work reported in it completed, without
the support we have received from the Wallace Laboratories, and specifically their Presi-
dent, Dr. F. M. Berger. We have received additional support for various investigations
from the U.S. Army, under contract DA-91-591-EUC-1458; and from the National
Institute of Mental Health. To them, and to the many subjects who took part in these
experiments, our sincerest thanks are due.
FOREWORD
THIS book is a report of a series of experiments, designed to test a theory regarding the
behavioural effects of certain groups of drugs. These are the so-called "depressant" and
"excitant" Cor "stimulant") drugs, which may be represented by sodium amytal, alcohol
and meprobamate on the one hand, and caffeine, Dexedrine and Meratran on the other.
The theory contends that these drugs act in such a fashion as to change the level of activity
of certain fundamental psychological mechanisms, which are derived from, and defined
in terms of modern experimental psychology, particularly modern learning theory. In
particular, it is suggested that depressant drugs increase inhibitory potentials and decrease
excitatory ones, while stimulant drugs have the opposite effect. In view of the fact that
the concepts of "excitation" and "inhibition" are operationally defined by means of certain
clearly demarcated experiments, the more or less rigorous deductions from a general
theoretical framework which constitute the hall-mark of the hypothetico-deductive method
can easily be transformed into experimental tests of the theory in question. It is the purpose
of this book to bring before the reader a number of such experiments, together with the
theoretical rationale underlying their development. It not may be entirely erroneous to state
that this mode of procedure has not usually been characteristic of modern psycho-
pharmacology, which has relied to an exaggerated extent upon blind empiricism, and has
abjured as almost sinful all dalliance with psychological theory (Trouton and Eysenck,
1960).
It is of course very likely, and may almost be taken as axiomatic, that these molar
psychological concepts of "excitation" and "inhibition" will have recognizable physio-
logical counterparts. If no such isomorphism could ever be demonstrated, even after
lengthy and determined study, then the writer at least would feel very doubtful about the
continued usefulness of the psychological concepts. At the present time no confident
physiological identification can be undertaken, although certain suggestive speculations
may occur to many readers familiar with the more recent studies o fthe ascending reticular
formation. A special chapter has been devoted to a discussion of these issues, but it should
be emphasized that interesting and promising as these links between psychology and physi-
ology appear, they have not yet reached the stage where they can be regarded as anything
but suggestive. For the time being, the psychological concepts must stand on their own
feet, and prove their worth, or lack of it, by the time-honoured test of all theories: the
prediction of facts previously unknown. It is by this test that the hypotheses put forward
in this book should be judged; we believe that the ratio of successful predictions is suf-
ficiently high to make further work along these lines distinctly worth while. It is our hope
that this feeling will also be shared by psychologists in other departments, and that
they will replicate our experiments, and extend them so as to bring into the net other,
hitherto untested, predictions; in order to be widely acceptable, a theory should receive
experimental support from a broader base than can be provided by a single department.
It has often been pointed out that scientific reasoning and argumentation resembles
a net or web, rather than a chain; the notion of the "nomological network" recently advo-
cated as providing a superior method of validation for psychological theories has found
adumbrations among logicians and philosophers of science at least since the time of
IX
X FOREWORD
Galileo - as will be seen by the quotation from Haller which opens this book. Three strands
in this network which constitutes our theory have already been indicated; modern learning
theory, psycho-pharmacology, and neuro-physiology. There is, however, a fourth strand
which may require special mention because it has not hitherto played much part in the
experimental study of drug effects, but which is quite central to our own approach to this
problem; that is the concept of personality. It is our belief that the main dimensions of
personality are related closely to the main physiological systems of the body, and if
excitation and inhibition are indeed as fundamental conceptions as modern learning
theory would have us believe, then it would seem to follow that there should be a corre-
sponding dimension of personality the two parts of which would be characterized, re-
spectively, by high excitatory and low inhibitory potential (the introvert), and by low
excitatory and high inhibitory potential (the extravert). The theory anticipates, of course,
continuous gradation between these extremes, but it does insist firmly on the close relation
between personality (as indexed by behaviour) and excitation/inhibition balance (as
indexed by laboratory test performance). Taking this hypothesis together with those
already discussed, we see that it must follow that depressant drugs have an extraverting
effect, while stimulant drugs have an introverting effect (Eysenck, 1957).
The relationships between these various concepts, all apparently lying at different
levels of discourse, are discussed in the first chapter, which takes up the task of "setting
the stage"It discusses the general way in which deductions can be made and predictions
v
derived from the various parts of the underlying theory; it also shows some of the diffi-
culties and dangers involved in too simple-minded and uncritical a reading of the theory.
It summarizes many of the experimental studies which have preceded the present volume,
and in which we have tested a wide variety of deductions. The remaining chapters each
deal with a single, clearly demarcated subject and state the logic of the reasoning, as well
as the general supporting evidence available for the various steps involved in the argument.
Sometimes it has been necessary to perform several experiments before the drug experiment
itself could be undertaken or interpreted; this usually happened when the chain of argu-
ment had in it a weak link which required additional work to be performed before we
would be reasonably sure in our own minds that the drug experiment could with advantage
be performed. This is one of the features which distinguish the hypothetico-deductive
approach from the less theory-oriented type of work that is perhaps more common in the
psycho-pharmacological field; much could be said about the relative advantages and
disadvantages of these different approaches.
It remains to state that while the Editor was responsible for the general theory which was
being tested in each of the studies here reported, and while he was always available to give
advice and help when requested, nevertheless each chapter represents the independent work
and thinking of the author, who alone is responsible for the deductions made and the con-
clusions drawn. In most cases the Editor would be in full agreement with what has been
written; in some cases he would be able to see arguments both for and against the contri-
butor's opinion; in one or two cases he would tend to disagree. It seemed much more
desirable to leave each contributor complete freedom to present his own case, even at the
risk of ending up with several unresolved differences (as in the case of the effects of drugs
on apparent movement, where the views of Costello and Sylvester are by no means in
full agreement!), than to try and enforce some monolithic uniformity by arbitrarily laying
down canons of interpretation. The reader, of course, may disagree with both Contributor
and Editor, and that is as it ought to be; the contribution made by a set of experiments
such as those discussed here lies in the experimental findings, and these may easily fit
FOREWORD Xi
in with theories quite different from those which inspired the work. Theories in science
are expendable; facts are not. Theories are useful in so fas as they lead to the discovery
of facts; as J. J. Thomson once said: "A theory in science is a policy rather than a creed".
We hope that the reader will agree with us that our policy has been a fruitful one; we
have no wish to impose a creed upon him, or upon ourselves.
H. J. EYSENCK
Natura in reticulum sua genera connexit, non in catenam: homines non possunt
nisi catenam sequi, cum non plura simul sermone exponere.
A. VON HALLER (1768)
xii
Chapter 1
PERSONALITY AND DRUG EFFECTS
H. J. EYSENGK
As pointed out in the Foreword, the experiments described in this book are
all concerned with the testing of deductions from a quite general theory,
and consequently a thorough understanding of this theory is important
if the empirical studies are to be properly evaluated. The more specific
theorems and hypotheses underlying the work described in the following
chapters are stated there, but it seemed necessary to discuss in some detail
the more general propositions, as well as some of the unresolved problems
and difficulties to which they give rise. This seemed particularly important
because the uses and abuses of theory in scientific work are not always
properly understood by workers in the fields of psychology and psychiatry;
much useless discussion may be avoided by clearly stating at the outset
just what our contentions are.
The first point to be made in an outline of our theory concerns the
postulation of two processes, entitled "inhibition" and "excitation". The
first writer to use these terms and concepts in roughly the way here intended
was of course Pavlov (1927); among those who have clarified their meaning
and added experimental content Hull (1943) must be particularly singled out.
Many other writers, from Dodge (1928; 1931) to Teplov (1959), have
contributed to the gradual clarification of these notions, but it would not
be correct to say that any agreed and unambiguous definition of these two
terms would be possible even now. To expect such a definition at this
moment would indeed be to misunderstand the way in which science
works and progresses. As Louis Pasteur has put it in his classic Études sur
la Bière, "Science is built up by successive solutions given to questions of
ever-increasing subtlety, approaching nearer and nearer towards the very
essence of phenomena." Advance is therefore gradual, and perfection is
not likely to characterize early or even intermediate stages of development.
It is one of the aims of this book to help in the slow and arduous process
which may ultimately lead to the proper understanding of the concepts of
"excitation" and "inhibition"; none of the contributors would imagine for
a single instance that such understanding had already been achieved.
Such an avowal of ignorance does not, however, imply that the use of
these terms, and the theoretical developments outlined below, are of little
or no value in guiding experimentation. Theories stand near the beginning
of the long road that leads to scientific laws, and their main value is that
of being guide-posts for the discovery of new facts which in turn will
enable better theories to be built. Just as bad maps are better than no map-
at all, so even a poor theory may be useful in leading to a better under-
standing of a given field of knowledge, through leading to more thorough
1
2 H. J. EYSENCK
exploration of the least well known parts, or those where discrepancies
are discovered between theory and fact. Near the end of the road, where
maps and theories are well-nigh perfect, they do not serve the purposes
of exploration any longer, because there is no further need for exploration;
theories have become laws, and serve only as memory aids summarizing
experimental results.
Granted, then, that we cannot define "inhibition", we can at least say
what kind of phenomenon is responsible for the postulation of a concept
of this kind, and we can give a rough-and-ready statement of the sort of
thing we shall intend by the use of the term. In its broadest meaning, then,
inhibition refers to a process within the C.N.S. which interferes with the
ongoing perceptual, cognitive and motor activities of the organism. The
type of interference intended can best be clarified by reference to the two
main types of inhibition, which may be called temporal inhibition and spatial
inhibition (Eysenck, 1957). Temporal inhibition refers to the accumulation
of a performance decrement as the result of the performance itself; it is
usually associated with massed practice, and can be elicited experimentally
in those situations giving rise to what Pavlov has called "internal inhibition"
and Hull "reactive inhibition". Spatial inhibition refers to the production
of a performance decrement through some other form of action occuring
simultaneously, or almost simultaneously; it is sometimes called "distrac-
tion" in common parlance, and is similar to Pavlov's notion of "external
inhibition". The terminology here suggested is preferred to that of Pavlov
or Hull because these authors have given to their own terms excess meaning
by incorporating them in a wider theoretical system, so that the use of
Hullian or Pavlovian terms might seem to imply acceptance of that system
as a whole*. Much as we admire the work of both scientists, we cannot
believe that at the present time the unchanged use of their theories could
properly be defended, so that more neutral terms seemed preferable.
We may now turn to the experimental paradigms which could be used
to define operationally the concepts of temporal and spatial inhibition.
Only a few of these will be mentioned here as no complete account of the
general theory could possibly be given within the confines of this chapter.
Consider then as one example the facts relating to the well-known phe-
nomenon of reminiscence (McGeoch and Irion, 1952). If a motor or perceptual
task is carried out by the subject under conditions of massed practice, i.e.
without or with minimal rest pauses, then the theory demands that he
should develop temporal inhibition; this inhibition, being a fatigue-like
state, should interfere with performance, and should dissipate during
rest after the termination of the scheduled performance. If, then, the
subject were asked to resume practice after the rest pause, then his per-
* The objections to Pavlov's physiological notions are too well known to require
restatement here (Konorski, 1940). Hull's concept of reactive inhibition is peripheralist
and tied to the idea of actual physical work done by the organism; neither of thes eviews is
tenable any longer (Eysenck, 1957; Broadbent, 1958). Our formulation escapes many of
the strictures which Broadbent has levelled against the Hullian theory; his own "filter"
type of hypothesis to account for the facts of inhibition, while plausible when perceptual
data alone are considered, breaks down when we attempt to explain reminiscence and
other similar phenomena.