Electrodermal Activity THE PLENUM SERIES IN BEHAVIORAL AND MEDICINE Series Editor: William J. Ray, Pennsylvania State University, University Park, Pennsylvania

BIOLOGICAL BARRIERS IN BEHAVIORAL MEDICINE Edited by Wolfgang Linden

ELECTRODERMAL ACTIVITY Wolfram Boucsein

HANDBOOK OF RESEARCH METHODS IN CARDIOVASCULAR BEHAVIORAL MEDICINE Edited by Neil Schneiderman, Stephen M. Weiss, and Peter G. Kaufmann

INTERNATIONAL PERSPECTIVES ON SELF-REGULATION AND HEALTH Edited by John G. Carlson and A. Ronald Seifert

PHYSIOLOGY AND BEHAVIOR THERAPY Conceptual Guidelines for the Clinician James G. Hollandsworth, Jr.

THE PHYSIOLOGY OF PSYCHOLOGICAL DISORDERS Schizophrenia, Depression, Anxiety, and Substance Abuse James G. Hollandsworth, Jr.

THE PSYCHOLOGY AND PHYSIOLOGY OF BREATHING In Behavioral Medicine, Clinical Psychology, and Psychiatry Robert Fried with Joseph Grimaldi Electrodermal Activity

Wolfram Boucsein University of Wuppertal Wuppertal, Germany

Springer Science+Business Media, LLC Llbrary of Congress Cataloglng-ln-Publlcatlon Data

8oucsein, WolfraN. Electrodermal activity I WolfraN 8oucseln. p. CN. -- (The Plenum series in behavioral psychophySiology and medicine.> Includes bibliographical references and index. ISBN 978-1-4757-5095-9 ISBN 978-1-4757-5093-5 (eBook) DOI 10.1007/978-1-4757-5093-5 1. Galvanic response. 2. Galvanic skin response• -Measurement. 3. Psychophyslology. 1. Tltle. II. Ser les. [DNLM: 1. Galvanic Skin Response. WL 106 8755el QP372.9.868 1992 612.7'91--dc20 DNLM/DLC for Library of Congress 92-49890 CIP

ISBN 0-306-44214-0

© 1992 Springer Science+Business Media New York Originally published by Plenum Press, New York in 1992

Ali 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 Foreword

Electrodennal activity was observed for the first time more than 150 years ago in Gennany where, a quarter-century later, the scientific study of psychology also origi• nated. Well into the 20th century, English-speaking psychologists alI read Gennan and, if they could, made pilgrimages to Leipzig and Heidelberg and other seats of Gennan scholarship. Then gradually the focus of psychological research, including the new field of psychophysiology, shifted to the United States and Britain. Studies of electrodermal activity in particular originated mainly in North America. As a student in the early 1950s, 1 leamed about what we then called the Galvanic Skin Response or GSR by reading C.W. Darrow, G.L. Freeman, R.A. Haggard, R.A. McCleary, and H.G. McCurdy, all in American English. The current renaissance of Gennan science has made it necessary for psychologists, once again, to attend to and leam from the work of their Teutonic colleagues. Fortunately for us monolingual Americans, English has become the lingua franca of our field; Gennan scholars speak our language fluently when they visit the United States and understand us when we go to them. The return of Gennan scholarship 10 what 1 shall loftily call the high table of psychophysiology is exemplified by this fme book, the most comprehensive treatise on the electrodermal system 10 appear in any language and now available in English. In 1971, in the eighth volume of the journal Psychophysiolo gy, Lykken and Venables commented, "Of a11 psychophysiological variables, the GSR can lay reasonable claim to being the most popular in current use. In spite of years of searching study, we are still surprisingly uncertain about the function, not 10 say the mechanism of this phenomenon. . . . Nevertheless, the GSR seems 10 be a robust sort of variable since, in hundreds of experiments, it continues s10utly 10 provide useful data in spite of being frequently abused by measurement techniques which range from the arbitrary 10 the positively weird." Now, more than twenty years later, the findings collected and integrated by Professor Boucsein should make it possible for future investigators 10 address this "robust sort of variable" with standardized technique and the respect that it deserves. Wolf Boucsein was educated at the University of Giessen and is now Professor of Physiological Psychology at the University of Wupperta1. He has published extensively in the areas of psychophysiology and differential psychology. In the present volume he

v vi has provided what should become the standard reference on the topic of electroclennal activity. David T. Lykken

University of Minnesota Preface

Since the discovery of the galvanic skin response over one hundred years ago, recording of electrodennal phenomena has become one of the most widely used meth• ods of measurement in various fields of psychophysiology. This book provides, for the fust time, a comprehensive summary of perspectives and histories from different sci• entific disciplines as well as a complete outline of methodological issues, and a review of results from the different areas of electrodermal research. The book is divided into three parts. Part 1 (Chapters 1.1-1.5) focuses on the anatomical, physiological, and biophysical origins of electrodermal phenomena. Pe• ripheral and central nervous system mechanisms are discussed, and fundamental bio• physical principles are provided together with an extensive discussion of the current electrical models of electrodermal activity. Part 2 (Chapters 2.1-2.6) outlines principles and methods of electrodermal record• ing, scoring techniques, and the action of intern al and external influences on the signal, and describes statistical properties of the different electrodermal parameters. It ends with a summary of recent discussions of the advantages and disadvantages of the dif• ferent methods. Part 3 (Chapters 3.1-3.6) reviews applications of electrodermal recording tech• niques within psychophysiology, personality research, clinical and applied psychology, and medical disciplines, for example, dermatology and neurology. Areas such as ori• enting and habituation, classical and instrumental conditioning, information processing and storage, multidimensional , sleep, and stress research are considered with respect to the theoretical modelling of vegetative concomitants of central nervous sys• tem phenomena. Aspects of specific validity of electrodermal measures are discussed within the framework of neurophysiological and psychophysiological systems. The present volume is conceptualized as a handbook. A reader who is not especially interested in the signal 's origins may start with Part 2, after having read the introductory Section 1.1.1 and the summary in Chapter 1.5. Readers having fundamental knowledge in electrophysics may skip Section 1.4.1, and aiso Sections 2.1.1 and 2.1.2. Since the book contains numerous cross-references to the different sections, starting from any point is possible without loss of content. Several chapters and sections end with summaries that provide the appropriate highlights (Chapters 1.5 and 3.6, and Sections 2.1.6,2.2.7, and 2.3.5). vii viii

Appreciation for adding to the book's content is given to my co-workers Riidiger Baltissen, JBm Grabke, Peter Kirsch, and Florian Schaefer as well as to Mik:e Dawson, Bob Edelberg, and John Furedy. I would like also to thank Ulrike Hillmann, Marlies Knodel, Brigitte Kapanke, and Boris Damke for doing the text editing, and Sebastian Boucsein, Katrin Boucsein, Martina Promeuschel, and Timothy Skellett for helping with figures, references, and language editing. In addition, I would like to thank Cecilia Secor, Judith Ray and especially Alex Vincent, who helped tremendously to improve my English, the latter one also for making several proposals that added to the content. Finally, appreciation is given to the series editor, Bill Ray, who performed agreat job getting the present volume published. Wolfram Boucsein Wuppertal, Germany, August 1992 Contents

1 Principles

1.1 Introduction ...... 1 1.1.1 Definitions and terminology ...... 1 1.1.2 Early history of electrodennal research ...... 4 1.1.3 Recent developments in electrodennal research ...... 6

1.2 Anatomy ...... , 7 1.2.1 Vertical structure of the skin ...... 8 1.2.1.1 The epidermis ...... 8 1.2.1.2 Dennis and subcutis ...... 12 1.2.1.3 Vascular system ofthe skin ...... 13 1.2.2 Horizontal structure of the skin ...... 13 1.2.3 Distribution and structure of sweat glands ...... 14 1.2.4 Other effector and sensor organs in the skin ...... 16

1.3 Physiology ...... 16 1.3.1 Efferent innervation of the skin ...... 17 1.3.2 Innervation of sweat glands ...... 18 1.3.2.1 Peripheral aspects of innervation ...... 20 1.3.2.2 Central aspects of sweat gland innervation ...... 21 1.3.2.3 Questions of double innervation and resting activity in sweat glands ... . 24 1.3.2.4 Specific innervations of sweat glands in different regions of the skin .. . 24 1.3.3 Functions of sweat gland activity ...... 26 1.3.3.1 Mechanism of sweat secretion and contents of sweat ...... 26 1.3.3.2 Thennoregulatory function of sweating and skin blood flow ...... 27 1.3.3.3 Other functions and more specific properties of ...... 28 1.3.4 Specific physiological mechanisms underlying electrodennal activity .. 30 1.3.4.1 Central origins of electrodennal activity ...... 30 1.3.4.2 Properties of skin and sweat glands influencing electrodennal activity .. 36 1.3.5 Suggested biological relevance of electrodennal phenomena ...... 40

1.4 Biophysics ...... 42 1.4.1 Resistor- and capacitor-based systems ...... 42 1.4.1.1 Some fundamental electrical dimensions ...... 43 1.4.1.2 Changes in RC circuits when DC is applied ...... 44 1.4.1.3 Changes in RC circuits when AC is applied ...... 49 1.4.1.4 Determining system properties of unknown RC systems ...... 54 ix x Contents

1.4.2 E1ectrophysical properties of skin and sweat glands ...... 56 1.4.2.1 Resistive properties of skin and sweat glands ...... 58 1.4.2.2 Capacitative properties of skin and sweat glands ...... 59 1.4.2.3 Origins of active electrical properties in the skin and sweat glands .... . 61 1.4.3 Models of the electrodermal system ...... 65 1.4.3.1 Models based exc1usively on resistive properties ...... 65 1.4.3.2 Models additionally inc1uding capacitative properties ...... 67 1.4.3.3 Specific advantages of AC methods in model building ...... 71

1.5 Summary of mechanisms ...... 76

2 Methods

2.1 Basic issues ...... 79 2.1.1 Principles of measurement ...... 80 2.1.2 Measuring with operational amplifiers ...... 83 2.1.3 Separating electrodermal reactions from levels ...... 86 2.1.4 Specific electrodermal recording problems ...... 88 2.1.5 Measuring electrodermal activity with AC ...... 90 2.1.6 Summary of recording principles ...... 95

2.2 Recording ...... 95 2.2.1 Recording sites ...... 96 2.2.1.1 Choice of sites ...... 96 2.2.1.2 Pretreatment of sites ...... 100 2.2.2 Electrodes and electrolytes ...... 101 2.2.2.1 Forms of electrodes and their attachment ...... 101 2.2.2.2 Bias potentials and polarization of electrodes ...... 103 2.2.2.3 Choice of electrodes and set up ...... 105 2.2.2.4 Cleaning, maintenance, and storage of electrodes ...... 106 2.2.2.5 Electrolytes and electrolyte media ...... 106 2.2.3 Measurement devices ...... 109 2.2.3.1 Endosomatic recording ...... 109 2.2.3.2 Exosomatic recording with DC ...... 110 2.2.3.3 Exosomatic recording with AC ...... 116 2.2.4 Methods of storage and evaluation of the electrodermal signal ...... 119 2.2.4.1 Paper recording and evaluation by hand ...... 119 2.2.4.2 Off-line computer analysis ...... 121 2.2.4.3 On-line computer analysis ...... 123 Contents xi

2.2.5 Sources of artifacts ...... 123 2.2.5.1 Artifacts stemming from recording ...... 124 2.2.5.2 Physiologically produced artifacts ...... 124 2.2.6 Techniques of electrodermal recording in specific contexts ...... 126 2.2.6.1 Long-term runs ...... 126 2.2.6.2 Recording simultaneously with different techniques ...... 128 2.2.6.3 Measuring with dry electrodes or liquid electrolytes ...... 129 2.2.6.4 Other specific electrodes and site arrangements ...... 130 2.2.7 Summary of recording techniques ...... 131

2.3 Scoring ...... 132 2.3.1 Parameters of phasic electrodermal activity ...... 132 2.3.1.1 Latency times and windows ...... 133 2.3.1.2 Amplitudes ...... 134 2.3.1.3 Reaction shape ...... 139 2.3.1.4 Area measurements ...... 146 2.3.2 Parameters of tonic electrodermal activity ...... 147 2.3.2.1 Electrodermallevel ...... 147 2.3.2.2 Tonic parameters derived from phasic changes ...... 148 2.3.3 Transformation of electrodermal parameters ...... 150 2.3.3.1 Taking the electrode area into account ...... 150 2.3.3.2 Transforming resistance into conductance units ...... 151 2.3.3.3 Improving distributional characteristics of EDA ...... 152 2.3.3.4 Reduction of interindividual variance ...... 153 2.3.4 Removing artifacts and treatment of missing data ...... 157 2.3.4.1 Identification of artifacts during measurement ...... 157 2.3.4.2 Missing data treatment and EDR magnitude ...... 158 2.3.4.3 Correction for EDL drift ...... 160 2.3.5 Summary of scoring techniques ...... 161

2.4 External and internat inftuences ...... 162 2.4.1 Climatic conditions ...... 162 2.4.1.1 Ambient temperature ...... 162 2.4.1.2 Other environmental conditions ...... 164 2.4.2 Physiological variables ...... 165 2.4.2.1 and skin blood flow ...... 166 2.4.2.2 Evaporative water 10ss and skin moisture ...... 167 xii Contents

2.4.3 Demographic characteristics ...... 169 2.4.3.1 Age differences ...... 169 2.4.3.2 Gender differences ...... 172 2.4.3.3 Ethnic differences and heritability ...... 174

2.5 Statistical properties ...... 178 2.5.1 Characteristics of endosomatic measurements ...... 178 2.5.1.1 Skin potential reactions ...... 178 2.5.1.2 Skin potentiallevels ...... 179 2.5.1.3 Relationship between endosomatic and exosomatic measurements . . .. . 180 2.5.2 Characteristics of exosomatic DC measurements ...... 181 2.5.2.1 Results of skin conductance measurements ...... 182 2.5.2.2 Results of skin resistance measurements ...... 185 2.5.2.3 Latency and rise time parameters ...... 187 2.5.2.4 Measures of recovery ...... 190 2.5.2.5 Relationship between measures of amplitude and shape ...... 191 2.5.3 Characteristics of exosomatic AC measures ...... 194 2.5.3.1 Recordings with sinusoidal current ...... 194 2.5.3.2 Recordings with square wave current ...... 196 2.5.4 Level dependence ...... 197 2.5.4.1 Dependence of treatment recordings on baseline recordings ...... 198 2.5.4.2 Dependence of phasic EDA on tonic values ...... 201

2.6 Summary of conceptual discussions ...... 205 2.6.1 Endosomatic versus exosomatic recording ...... 206 2.6.2 Constant current versus constant voltage recording ...... 208 2.6.3 Using direct versus alternating current ...... 211 2.6.4 DC versus AC coupling ...... 212 2.6.5 Resistance versus conductance units ...... 213

3 Applications

3.1 Stimulus-related psychophysiological paradigms ...... 217 3.1.1 Electrodermal indices of orienting and habituation ...... 218 3.1.1.1 EDR as an indicator of orienting responses ...... 219 3.1.1.2 EDR in differentiating orienting from defensive reactions ...... 222 3.1.1.3 Electrodermal indices of habituation ...... 225 Contents xiii

3.1.2 Conditioning of electrodermal reactions ...... 23Z 3.1.2.1 Classical conditioning of electrodermal reactions ...... 233 3.1.2.2 Instrumental or operant conditioning of the EDR ...... 239 3.1.3 Electrodermal indices of information processing ...... 244 3.1.3.1 Neurophysiological considerations on EDA and information processing 244 3.1.3.2 EDR and processing capacity ...... 248 3.1.3.3 EDR and information storage ...... 253 3.1.3.4 Hemispheric asymmetry and electrodermallateralization ...... 254

3.2 Generalized psychophysiological states ...... 260 3.2.1 Electrodermal indices of arousal ...... 261 3.2.1.1 EDA as an indicator of general arousal ...... 261 3.2.1.2 EDA during states of motivational arousal ...... 264 3.2.1.3 EDA during sleep stages ...... 273 3.2.2 Electrodermal indices of emotion and stress ...... 277 3.2.2.1 EDA in emotional states ...... 277 3.2.2.2 EDA as an indicator of stress ...... 284

3.3 Personality and individual differences ...... 292 3.3.1 General traits ...... " ...... 292 3.3.1.1 EDA and extraversion-introversion ...... 293 3.3.1.2 EDA and emotionallability ...... 297 3.3.2 Specific traits ...... 299 3.3.2.1 Traits based on questionnaire data ...... 299 3.3.2.2 Electrodermallability as a trait ...... 302

3.4 Psychopathology ...... 305 3.4.1 EDA in the assessment of anxiety, , and depression ...... 306 3.4.1.1 EDA in patients with generalized anxiety and phobias ...... 306 3.4.1.2 EDA in psychopathic or antisocial disorders ...... 310 3.4.1.3 EDA in depressive patients ...... 316 3.4.2 Electrodermal indices in schizophrenia research ...... 320 3.4.2.1 Electrodermal recovery and vulnerability for schizophrenia ...... 321 3.4.2.2 Electrodermal nonresponding in schizophrenics ...... 325 3.4.2.3 Other issues in schizophrenia research related to EDA ...... 332 3.4.3 EDA as an indicator in psychopharmacological treatment of anxiety .. . 335 3.4.3.1 Studies with benzodiazepines ...... 337 3.4.3.2 Studies with beta-blockers and neuroleptics ...... 340 xiv Contents

3.S Miscellaneous applications of EDA ...... 343 3.5.1 EDA in various fields of applied psychology ...... 343 3.5.1.1 EDA in engineering psychology ...... 343 3.5.1.2 EDA in detection of deception ...... 349 3.5.2 EDA in medicine ...... 359 3.5.2.1 EDA in dermatology ...... 359 3.5.2.2 EDA and neurological disorders ...... 363 3.5.2.3 EDA in other medical disciplines ...... 369

3.6 Summary and outlook ...... 372

References ...... 375

Subject Index ...... 421

Appendix ...... 432