Theoretical Issues in Stuttering [2 ed.] 1138640530, 9781138640535

Table of contents :
CONTENTS
ILLUSTRATIONS
PREFACE
ch1 THE SEARCH FOR UNDERSTANDING
ch2 THE ROLE OF THEORY IN THE SCIENCES
ch3 EVALUATING THEORIES
ch4 HISTORICAL PERSPECTIVES ONSELECTED PAST AND PRESENTTHEORIES OF STUTTERING
Influences of the zeitgeist
Psychology (a very brief history)
Psychoanalysis
Cerebral dominance
Neurophysiology
Culture and language
Chaos theory
Conclusion
ch5 WHAT SHOULD A THEORY OFSTUTTERING EXPLAIN?
ch6 THEORIES OF STUTTERING - Speech motor control
Introduction
Sensory-motor modelling theory
The interhemispheric interference model
The variability model
Speech motor skill theory
Speech concatenation theory
The Packman and Attanasio 3-factor model of moments of stuttering
FIGURE 6.1 The Pack111a11 and Attanasio 3-factor model of mo111ents of stuttering
Factor 1: Impaired neural processing for spoken language
Factor 2: Triggers
Factor 3: Modulators
Extended GODIVA model
ch7 THEORIES OF STUTTERING - Cognitive and linguistic processing
The anticipatory struggle hypothesis
The covert repair hypothesis
The vicious circle (cycle) hypothesis
EXPLAN
The variable release threshold hypothesis
ch8 THEORIES OF STUTTERING - Multifactorial models
The demands and capacities model
FIGURE 8.1 A simple linear cause-effect model that emphasizes constitutional factors
FIGURE 8.2 A simple linear cause- effect model that emphasizes environmental factors
FIGURE 8.3 A complex linear cause-effect model that emphasizes relationships between capacity and demand
The dynamic multifactorial model
Commentary on multifactorial models
ch9 THE EVOLUTION OF THEORIES
Evolution of theories of stuttering
Packman and Attanasio 3-factor causal model of moments ofstuttering
Extended GODIVA model
Variable threshold release (VRT) hypothesis
ch10 THEORY AND TREATMENT
Introduction
Therapy based on theory
Effective therapy as confirmation of theory
The proof of the pudding is in the evidence
The necessity of causal theory for treatment
Atheoretical treatment: an example
Theories as potential sources of error in the selection of treatment
From treatment to theory
Postscript
REFERENCES
INDEX

Citation preview

'Theoretical Issues in Stuttering is unique in several ii11portant respects. One distinctive feature of the book is that theories of stuttering are 11ot only described but systematically con1pared with respect to the criteria of testability, expla11atory power, parsimony, and heuristic fruitfi.1lness. 111 this way an integrated vievv 011 quite different theoretical approacl1es is syste1natically developed a11d described. Anotl1er singular featL1re of this book is that the frrst tl1ree cl1apters deal -vvith philosophical questions bellind tl1eo1ies of stutteting. In su1n, tl1is book is exceptionally clearly a11d co111prehensibly vvritten and provides i11sights into the philosophical background of stt1ttering theories, tl1eir developn1ent and evaluation.' Hatis-Georg Boss/1.ardt, retired men1ber of Faculty of Psychology, Ruhr-University Bochu1n, Gern1any 'This second edition of Theoretical Issues i11 St11tferi11g is 111uch anticipated, given the 011going proft1sion of 111odels and theories about the cause of stutteri11g. This book is an indispensable guide to tl1ose wanting to knovv about current causal models and theories of stuttering and how to evaluate then1, written by two authors with extensive experience of treat111e11t, teacl1ing, research and publishing about the disorder. The first half of the book provides guidelines for evaluating theories, such as testability and explanato1y value. The authors draw on philosophy of scie11ce and psychology to develop those guidelines. Seven nevv models and theories have been added to this editio11, along with a 11evv chapter about the evolutio11 of theories. ' Mark Onslow, Director, Australian Stuttering Research Centre, The University of Sydney, Australia

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THEORETICAL ISSUES IN STUTTERING

Despite decades of research into the i1ature and treatment of stutte1ing, the cause and underlying rnechanisms of it are still not well understood. In this unique and comprehensive overvie\v of the numerous theories and models \vl1icl1 seek to understand and explain stutte1ing, the authors of Theoretical Issues in Stuttering provide an invaluable accou11t. Covering an impressive range of topics including past a11d current tl1eories of stuttering, this editio11 provides the reader with an updated evaluatio11 of the literature on the subject of stuttering alongside explo1ing the evolution of ne"\ov theories. Placing each within the relevant historical context, the at1thors explore the contribution of theory to both understanding and managi11g stuttering. Theoretical Issues in Stuttering is a critical account of the models and tl1eories which surround the su bject of stutteril1g, aiming to act as a key resource for students of speech-language pathology as well as for lecturers, clinici a11s a11d researchers within the field.

A nn Packman l1as vvorked for over 35 years in the field of stuttering, as clllrician, teacl1er and researcher. Sl1e has published over 150 articles i11 peer-revie\ved journals and has served two terms as Associate Editor for Flt1ency for jot1rnals of the A1nerican Speech and H eari11g Association. Professor Joseph S. Attanasio has published and presented on the topic of stuttering in national and international research journals and venues duri11g his 45 years as a 1nen1ber of the D epart111ent of Co1n1nu11ication Science & Disorders, M ontclair State University .

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THEORETICAL ISSUES IN STUTTERING Second Edition

Ann Packman and Joseph S. Attanasio

i~ ~~~;~;~~;up LONDON ANO NEW YORK

Second edition published 2017 by Routledge 2 Park Square, Milton Park, Abingdon, Oxon, OX14 4RN and by R outledge 71 1 Third Avenue, N e w York, NY l 0017

Ro11tledge is 1111 i111pri111 qf the Taylor & Frauds Group,

1111

i1!fori11a b11si11ess

© 2017 Ann Pack1nan and Joseph S. Attanasio The right of Ann Pac kn1an and J oseph S Attanasio to be identified as autho rs of this \vork has been asserted by theLn in accordance \Vi th sections 77 and 78 of the Copyright, Designs and Patents Act 1Q88. All rights reserved. N o part of this book rnay be reprinted o r reproduced or utilised in any fonn or by an y electronic, nlechanical, or other 1neans, 110\V kno.,,vn or hereafter invented, including photocopying and recordin g, o r in any infonnation storage o r retrieval syste1n, \Vithout perntission in \vriting fron1 the publishers. Trademark notice: Product or corpo rate na111es n1ay be trade1narks or registe red trade rnarks, and are used only for identification and explanation without intent to infringe. First edition published by Routledge in 2004

British Ubrc1ry Catalog11i11g in P11biicatio11

D11111

A catalogue record for this book is available fron1 the British Library

Ubrary o_f Congress Cataloging in ])1.1/J/ication Data Na111es: Packinan, Ann. I Attanasio, Joseph S. Title: Theoretical issues in stutte1ing I Ann Packn1an and Joseph S. Attanasio. Other titles: Stuttering D escription: Second edition. I Abingdon, Oxon ; N e"v York, NY: Routledge, 2017. I Includes bibliograpltical references. Identifiers: LCCN 20160567871 ISBN 9781138640528 (alk. paper) I ISBN 9781138640535 (alk. paper) I ISBN Q781315636559 (alk. paper) Subjects: LCSH: Stuttering. I Speech disorders. Classification: LCC RC424 .P33 2017 I DOC 616.85/ 54--dc23 LC record available at https:// lccn.Joc.gov/ 2016056787 ISBN: 978- 1-138-64052-8 (hbk) ISBN: 978-1-138- 64053-5 {pbk) ISBN: 978-1-315-63655-9 (ebk) Typeset in B en1bo by Saxon Graphics Ltd, Derby

CONTENTS

•

List of illustratio11s Preface 1

...

Xlll

1

The search for t111derstanding Seeking explanation 2 Causality and stutteri11g 3 Causality: issues of logic 5 A Realist view of causality 6 Establishing cat1se: necessary and sufficient conditions The causal field 9 Distal and proxi111al cause 11 D efmitions 12 Fallacies of causal reasoning 13

2

XL

The role of theory in the scier1ces Theory in the physical sciences 16 Kuh11 and scientific revolutio11s 19 Theory in tl1e hu1nan scie11ces 21 Paradign1s 23 Laws 23 Theories 24 H ypotheses 25 Models 26 Pseudoscience 29 Note 29

8

16

viii Contents

3

31

EvalL1ating theories Testability and falsifiability 32 Explanatory power 36 Parsimony 37 H euristic value 38 SL1nu11ary and discussio11 39

4

Historical persp ectives 011 selected past and present theories o f stL1tteri11g Influences of the zeitgeist 41 Psychology (a very brief histo1y) Cerebral domjnance 45 Neurophysiology 46 Culture and langu age 4 7 Chaos theory 50 Conclt1sion 52

5

41

42

53

What should a theory of stuttering explain? The problem of definitio11 54 Operationalizing stuttering 56 T opography 60 Onset and develop1nent 60 Natural recovery 63 G en etics 63 Variability 65

6

Introduction 6 7 Sensory-n1otor 111odelling theory 69 The interhe11uspl1eric interference n1odel 7 4 The variability 1nodel 80 Speech n1otor skill theory 86 Speech con ca tenation theory 88 The Packma11 and Atta11asio 3-factor model of mo111ents of stutte1i ng Extended GODlVA model 98

7

67

Theories of stuttering

Theories of stL1tteri11g The a11ticipatory struggle l1ypothesis 102 The covert repair hypotl1esis 109 The vicious circle (cycle) l1yp otl1esis 116 EXPLAN 120 The variable release threshold hypothesis 125

93

102

Contents ix

8 Theories of stuttering: n1ultifactorial n1odels

129

The dema11ds and capacities 111odel 129 The dynamic multifactorial n1odel 137 Comrne11tary on n1ultifacto1ial nlodels 146

148

9 The evolu tio11 of theories Evolution of theories of stuttering

149

10 Theory and trea t111e11t Introduction 1.52 Therapy based on theory 153 Effective therapy as co11£i.1mation of theory 154 The proof of the puddi11g is iJ1 the evidence 156 The necessity of theory for treatment 157 Atl1eoretical treat111ent: an exan1ple 157 Theories as potential sources of error ill the selection of treatment Fro1n treat1nent to theory 160 Postscript 161

References Index

152

159

162 176

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ILLUSTRATIONS

Figures

1.1 2.1 2.2 2.3 2.4

2.5 6.1 8.1 8.2 8.3

The three domains of inqt1iry The process of induction, deduction and experi111entation . . 1n science Sin1ple linear cause-effect model Complex linear cause-effect model Interactional model Transactional 111odel The Packn1a11 and Attanasio 3-factor model of n1ome11ts of stt1 ttering A simple linear cat1se-effect n1odel that ei11phasizes constitutional factors A simple linear cat1se-effect n1odel that e1nphasizes ei1vironn1ental factors A con1plex linear cause-effect inodel that emphasizes relationships between capacity and demand

5 19 28

28 28 28

93

132 132 133

Table

3.1

Criteria for evalt.1ating theories and qt.1estions to be asked of theories

39

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PREFACE

It is now at least 12 years si11ce tl1e first edition of this text and a lot has happened in the field of stt1ttering since the11. For example, at the time of writing tl1ere are three research articles on stuttering it1 the current issue ofjournal ef Speech, Language and Hearing Research, one randomized control trial of treat111ent a11d two on the development of meast1re1nent procedures. In terms of searching to clarify causal isst1es, ot1r understanding of the role of the brain in stt1ttering has been greatly enhanced by the plethora of brain itnaging research durmg this time. This is no doubt a result of technical advances in the field. It is now becoming clear that understanding the neural u11derpinnings of stuttering will contribute greatly to understanding why people stutter a11d why so inany things about the disorder are yet to be explained. This growing understanding of the role of the brain in stutterit1g 11as resulted ill the publication of nevv theories, inodels and/ or hypotheses during the last 12 years. We are delighted to include seven new theories in this second editio11. We have selected theories that are syste1natically developed and expansive e11ough to allovv for ciitical analysis to take place. Theories that appear to be sketchy or vague ill their forn'lulatio11s and constructio11s have not been included. W e l1ave dropped a few of the older ones, i1ot because tl1ey have been refuted but because tl1ey 11ave not been 1nentio ned i11 tl1e intervening period or, on the face of it, see111 no lo nger relevant in the curre11t discot1rse about cause. The structure of this seco11d edition is n1uch the sa1ne. It starts with. chapters o n how to evaluate ca usal tl1eory, drawing o n the history and philosophy of science and psychology. W e the11 go on to evaluate current causal theories of stuttering, using criteria developed i11 these chapters. The presence of rival or conflicting causal theories in the literature can be confusing, especially for practitioners ir1 the field, and our pri111ary ai111 in this te)ft is to provide readers \Vith tl1e tools to assess

xiv Preface

the 1nerits of new theo1ies as they a1ise. We have also included a ne\¥ chapter on how theories can evolve over til11e with the publication of 11ew research findings. We vvish to acknowledge here tl1at we have co11tinued to use tl1e term 'stt1tterer' in this text, a tenn that we appreciate can be seen by so1ne as demea11ing. We do so ptimarily becat1se tl1e term is used freqt1ently in historical accounts of stutteri11g tl1at are covered in this text. We are conlforted by the fact, l1owever, that the tern1 is also used by people wl10 stt1tter. We re1nain indebted to Terry McMuller1 for infon1ung our tllinkii1g abot1t cause, to our publishers for tl1eir invitation to write this seco11d ectitio11, and to Brian and Matie for their ongoing patience and support. Ann Packn1an and Josepl1 S. Attanasio Theory helps us to bear our ig11orance of fact. George Santayana

THE SEARCH FOR UNDERSTANDING

In his novv classic text on the nature of stuttering, Charles va11 Riper (1972) described stuttering as 'a puzzle, the pieces of which lie scattered on the tables of speech pathology, psychiatry, neurophysiology, genetics, and many otl1er disciplines ... we suspect that some of the essential pieces are not merely misplaced but still rnissing' (p. 2). Van Riper's \.Vords might aptly be applied to the difficulties we continue to face in understanding stuttering in the early part of the twenty-first century. Stt1ttering has probably existed fro111 the time ht1n1a11s began to speak, it exists in all cultures, and is present in around 1 per ce11t of the population at any one time. Yet, despite the fact that stuttering has been studied exte11sively, elen1ents of its puzzling and enig111atic nature continue to challenge 1nany contemporary students, clinicians, and researchers. What kind of disorder is it that u11explainably manifests itself i11 children after a period of apparently 11orn1al speech development? Why does stuttering take the fo1m, at least in its early presentation, of the repetition of speech sou nds a11d syllables? How is it that a cllild wl10 stutters can speak witl1out stuttering for 11ours, days, weeks - even mo11ths and possibly years - only to experience a return of the disorder? Why do son1e children who start to stutter continue to do so into adulth ood, while others recover naturally within a few years of onset? What 1nechanisms lie behind the ftue11cy-induci11g effects of singi11g and choral speaking or reading; of speaking along vvitl1 tl1e rhythmic beat of a n1etrono111e; of delaying, altering or rnasking the auditory feedback of the stutterer's own voice; or of prolonging speech or reducing its rate? Does one n1echanism accou11t for these fluency-inducing effects or are there a number of nlechanisn1s that co111e into play? Why does tl1e person who stutters say some \¥ords fluently but not others? The foregoing questions and others like then1 continue to capture the atte11tion of professionals a11d laypersons alike, a11d they underscore the puzzle that is stuttering. Nevertheless, vvhile rnuch is unknown about the disorder, there is an

2

The search for understanding

exte11sive body of scientific research that gives hope for our ultin1ate ability to u11wrap the nature of stutte1i11g, divest it of its myste1ious11ess, a11d develop ways to treat it effectively. Indeed, a great deal of progress in those directions has been n1ade recently, especially in tl1e area of brain researcl1. Despite the progress, the questions posed above continue to pro111pt n1uch tl1eorizing about stuttering. The discussio11s that follow in this text are designed to organize, n1ake sense of, and evaluate a nu1nber of theories of stuttering and to place theorizing about stutteri11g it1to tl1e broader fran1ework of the nat11re a11d philosophy of scien.ce. This vvould seem to be a necessa1y context for thinking critically about the r1ature a11d cause of stuttering, and for questioning the logic of our propositions about stutteri11g.

Seeking explanation Asking for an explar1ation is to ask wl1y something is the vvay it is. We expect a u1hy question to yield a because answer. This why /because connection is 'a call for understanding that thing' (Va11 Ca111p, 2014, p. 112). H un1ans crave explanation. We beco1ne uneasy when we are faced with things or happenings that we do 11ot u11derstand. This need for expla11ation develops early iI1 life, as can be seen in the well- known 'Why ... ?' questio11s of 2- 3- year-old children. The need for explanation \¥as also clearly evident in primitive humans, w ho presumed that the gods caused events such as the ert1ption of volcanoes, for vvhich they could see no other cause. This eased their discomfort at bei11g unable to explain or control r1at11ral pheno111ena and led to various ritualistic practices such as dancing for rain or offeri11g sactifices to appease the gods (van H ooft, Gilla1n & Byrnes, 1995). We no\¥ know that 111a11y of tl1ese ancient beliefs and explanations about the 11atural world are not 11ecessa1ily true. We now understand a great deal about \..'Perimental investigation. According to Chalmers (1999), theories are 'speculative and tentative conjectures or guesses freely created by tl1e hur11an intellect in an attempt to overco111e problen1s encountered by previoL1s theories to give an adequate account of son1e aspects of the world or universe' (p. 60). Althougl1 it n1ay be that a theory in its initial state is a speculative conjecture or guess, it ca11not re1nain as such if it is to be considered scie11tific. Scientific theories are 11ot uninformed gt1esses, musings or mere notions, speculations or guesswork. They are not based on personal preference or prejudice, nor are they dogt11atic staten1ents in the fo1n1 of unverifiable assertions. This is not to st1ggest that scientists and researchers do not have personal preferences in regard to what they choose to investigate or that they do 11ot begin

The role of theory in the sciences

17

their work after 11aving speculated on the nature of the pheno111enon of interest. It would be e1Toneou.s to suggest that tl1e perso11al curiosity of the scientist or researcher plays no part in undertaking a researcl1 proj ect. A scientist who is not curious or w ho does not speculate is obviously i11 the wrong li11e of work, and it woL1ld be a sad state of affairs if scientists found 110 personal joy or satisractio11 i11 \Vhat they do. It is \vhen scientists put their theories to tl1e test and attempt to validate those theories that personal preferences and prejudices 111ust be put aside and tl1e data or findings be allowed to speak for themselves. The beginnings of a theory, then , n1ay come fror11 the personal speculation a11d curiosity of the scientist, bt1t even then the formttlation of a theory is guided by modes of scientific thi11king and is often influenced or pro111pted by the scientific climate of its day. For exan1ple, evolution as an explanation of the origin and variety of species did not start with Charles Darwin; the scientific co1nmunity of vvhich he was a part was considering it before he for111t1lated his own version evolution was 'in the air'. Darwi11 was searching for a11 explanation of how evolution worked, an explanation that did not require the role of i11telligent design or a st1pren1e being. His search (and that of Alfred Rt1ssell Wallace) e11ded in tl1e adoption of natural selectio11 as the explanation. As suggested in the previous chapter, although there may be tin1es \vhen the two agree or overlap, scie11tific explanations are not sy11011yn1ous witl1 conunonsense notions of 11ow the world works. It n1ay be con1n1011 sense to get in fron1 being out in the rain for 111ar1y reasons, but science tells us tl1at viruses, not th e rain, ca use colds. Indeed, tl1e ft111ction of science is to uncover relatio11slups betvveen variables that are not appare11t througl1 co111mon sense. In their developed for111, scientific tl1eories are explanations supported by a sufficient amount of £-ictual evidence (Nevvton, 1997). They are constructs of ho\¥ things work and they generate testable hypotheses or predictions that, if borne out, provide support for the tl1eory and contribute to its validity. Results fro1n hypothesis testing or the predictions made must be observable. A scie11tific theory is one that is able to describe and predict future states and extend research by generating new ideas (Dunbar, 1995) or proble1ns to investigate and solve. Theories, then, are not simply descriptions or catalogues of current states. Rather, they explain or predict by generating testable hypotheses that are able to yield empirical data or observable results. Theories, therefore, lead to experimentation. The enterprise has a built-in self- correcting inechanism: if tl1e hypotheses or predictio11s are not upheld, then the theory 111ust be revised, modified or ultin1ately abandoned. Indeed, theories 111ust fit the facts and the co111111ent that we have all heard, that 'it works in theory but not in practice' can be see11 as being illogical in light of this self-correcting 1necharusn1. Theories provide a conceptual framework witl1in whicl1 facts are n1ade intelligible. In so doing, theories are organizing statem ents that 111ake connections among vvhat migl1t n1istaker1ly be v1evved as isolated facts. Research, however, niay be undertaken in the absence of a theory to guide it. In the early stages of investigation, researchers may be involved in gatl1ering and

18 The role of theory in the sciences

organizing facts or data, pro111pted by the need or desire to know or u11derstand n1ore about what interests them. In son1e instances, observations or facts inay con1e to researchers unbidden by the1n. As the facts or data accun1ttlate, tl1eories to explain them and connect tl1e111 to one another inay e1nerge. Indeed, without the e1nergence of theo1y, researcl1ers do not have a 111ecl1anisn1 to explain the accumulated facts, nor do they have a vision to guide the111 or a clear path to take for continued investigation. Wynn and Wiggi11s (1997) describe the following seqt1ence as being characteristic of the scientific n1ethod. As repeated observations are 111ade of a specific phe1101nenon or event, an assertion is 11-i.ade, tlrrough a process of inductive reasoning, that casts those observations into a state111ent or hypothesis that describes the general nature of the observed event or phenon1eno11. The hypothesis is the11 used to 111ake predictions that are consistent with the hypothesis. Reasoning fron1 the hypothesis to the prediction is by dedt1ctio11 rather than by induction. The prediction is then tested through experimentation desigi1ed to determine if the prediction is correct or if w hat is predicted actt1ally occt1rs. If the prediction is correct, the hypothesis is upl1eld. If the experiment £1.ils to yield results tl1at support the predictio11, the hypothesis is not upheld a11d n1ust either be 1nodified or abandoned. Wy11n a11d Wiggins view hypotheses as tentative and without a sufficient amot1nt of experiJ11entally confir111ed predictions or evidence to allow fmn state1r1ents to be 111ade. Tlus process ofinduction and deduction is shovv11 in Figure 2.1. Once a body of evidence is developed, the data may be sunu11arized in t11e form of a lau1. A scientific law is a state1nent, conf1nned by repeated observation or experi1nentation, of how a give11 aspect of natt1re works. '(A law] is a state1nent of some kind of regularity in nature' (Wynn & Wiggins, 1997, p. 3). A theory n1ay next be developed to explain the, 'underlying causes of the law's regula1ities' (Wynn & Wiggins, 1997, p. 113). We stated previously that hypotheses are derived fron1 theories yet here we report that, according to Wy11n and Wiggins (1997), theories are developed so1ne time after corroborated hypotheses have been gathered. Which co1nes first, hypotheses or theories? Not quite the 'crucken/egg' problem, but the answer to the question is problernatic and not straightforward. One finds in the literatt1re on the philosophy of science that the two terms are used interchangeably by the sa1ne writer or ar e used to mean the same thing by different writers or are t1sed to show a specific progression (i.e., fro111 theory to hypotl1esis). Tllis seenling confusion or inco1LSistency in tl1e use of the tern1s will be seen later in the text, where cat1sal explanatio11s of stt1ttering are refe1Ted to vaiiously by their originators as hypotheses, 11-i.odels or tl1eories. It may very well be the case, however, that the empirical and. tl1eoretical domains overlap, to the extent tl1at it is possible to have theories ge11erating 11ypotheses in certain stages of scientific investigations and to have hypotheses leading to tl1eories in other stages. Figure 2.1 suggests such a possibility. In tl1e end, careful reading of a given author's intended use of these ter111S tern1 is required. A fevv words are needed here about n1odelling. A 111odel is a forn1 of theo1izing. One of the functions of n-i.odels in science is to 'describe and help tis to understand

The role of theory in the sciences

THEORETICAL DOMAIN

EMPIRICAL DOMAIN

FIGURE 2.1

Development of ttieoll')'

Formulation

of hypotheses

Facts acquired throu.gh

obs-ervation

andl experi rnentation

ID eduction

19

Explanation and prediction

EmpiricaJ testing of hypotheses

The process of inductio11, deduction and expe1in1e11tatio11 in science

complex systen1s' (Chapa11is, 1963, p. 113). They do this by 'replacing intricate and complex systems with si1npler and more fanliliar a11alogies' (Chapanis, 1963, p. 114). They can also help us to see new relationships between variables or help us see relationships in 11ew vvays. There are many types of 11'1odelling in the various sciences, and indeed the tern1 1nodel is used quite loosely, ofte11 being used intercha11geably with the ter1n theory. According to Chapa11is, tl1ere are tvvo 111ain categories of nlodels: replica inodels a11d syn1bolic models. R eplica models are tangible, whereas sy111bolic n1odels make use of ideas, concepts, and abstract sy111bols, sucl1 as boxes and arrows. T hey are typically scl1en1atic. We return to the use of modelling in more detail in tl1e following secti on on theory in tl1e human . sciences.

Kuhn and scientific revolutions In his discussion 011 the en1ergence of scientific theories, Kul1n (1996) outlined a process that begins vvith the occurrence of an anomaly and ends with a paradigm shift. Kuhn (1996) applied tl1e word paradigm to 'the legiti111ate proble111s and methods of a research field' that have two primary characteristics: the acl1ievements of the research field are 'sufficiently u11precedented to attract an enduring group of adherents avvay fron1 competing modes of scientific activity. Simultaneously, [they are] sufficiently ope11- ended to leave all sorts of problems for the redefined group of practitioners to resolve' (p. 10). A paradigm includes a theory, but also research qt1estio11s that are seen as the appropriate ones for investigatio11, tl1e vocabulary and syn1bol systen1 that scientists use to describe their research field, and agreed-to research nlethods and it1stru1nents. An ano1naly is an eve11t, observatio11, occurrence o r phenon1e11011 that is unexpected vvithin the co11text of a11 existing received paradign1; it is a violatio11 of what \vould be expected under tl1e existing paradig111. Norn1al scie11ce, in Kuhn's ter111s, proceeds under an accepted paradign1 and is qt1ite successfu l in building knowledge. Kuhn (1996) defines nor111al scie11ce as 'research firmly based upon. one or more past scientific achieve1nents, achieve111ents that son1e particular scientific conm1un.ity acknowledges for a ti1ne as supplying the foundation for its furtl1er practice' (p. 10).

20 The role of theory in the sciences

It enco11-ipasses a body of accepted theory and its applicatio11s and experi111ents. It does not seek novel facts or theories. Eventually, l1owever, novelty or the unexpected does occur; son1ething ano111alous is encountered. For Kuhn, this is the first step to scientific discove1y. Tl1e scientific con11nunity's response to the ano111aly takes the form of a crisis. That is, a period of professional insecutity follows the occurrence of the anomaly. T l1e existing paradig111 is threate11ed a11d t1nable to ae,lequately account for the anomaly. The next step in the chain of events that leads to a paradig11-i sl1ift is tl1e scientific co1nn1unity's response to the crisis. Initially, the existing paradign1 is not abandoned because scientists do not view the anon-ialy as a contradiction of the existing theory and they acknovvledge that there are always discrepancies between theo1y and observation. According to Kuhn, scientists will atten1pt to reconcile the anomaly and the existing theory by qualifying or modifying the theory. For a full-blown c1isis to develop, the anon1aly inust be seen as son1ething fu11da1nental or extraordinary. Then, the ano111aly con1es to be recognized by more and more scientists as requiring attention. Finally, a paradig111 shift takes place; a i1ew paradigin beco111es necessa1y to acco1nmodate vvhat was ano111alous under tl1e forn1er one. Kuhn i1-iakes the point that a theo1y is abando11ed only wl1e11 there is another to take its place and that falsification by direct co111parison to nature is not a sufficient reason to reject an existing theo1y. The decision to reject one paradign1 is al\vays dependent on the decision to accept another paraclig111. Both paradigms are co1npared to eacl1 other a11d to 11ature (Kuhn, 1996). For K11hn, paradigni choice is not based on logic and experiinentation alone. Debate, persuasion, and finally, 'tl1e assent of the relevant con1111unity' (Kuhn, 1996, p. 94) - tl1e community of scientists - are very much a part of the acceptance of a new paradigm. These last criteria for paradign1 choice are 111ost likely what Kuhn's critics have called his relativisn1 a11d subjectivis1n. We have spent son1e tin1e investigating the contribution of Kul111 to the discussions abot1t the role of theo1y in science. However, Kuhn's position here has not gone unchallenged. Popper is another of the twentieth century's most infitiential thinkers on the nature of science and the role of scientific theories. Popper's primary contribution to the area was his theory of refutation. 111 short, Popper proposed that science is 11ot concerned with proving theories but vvith disproving the1n. We rett1r11 to tllis in Chapter 3, when we discuss evaluating theories. P opper's views are ofte11 contrasted with those of Kuhn . 111 £1ct, P opper hin-iself 111ade the contrast. Popper believed tl1at he and Kuhn agreed 011 tl1e notion of falsifiability and on the, 'i111possibility of conclusive proofs of falsificatio11' (Popper, 1999, p. xxxii) and their role in scientific revolutions. Popper asserted tl1at whereas he was con111litted to tl1e ancie11t theo1y of proof, Kuhn was affected by relativis111 and subjectivis1n. Both Popper (1999) and Kulm (1996) hold that the choice of a theory cannot be based on the kind of proof used in n1athematics or logic. Still, there do appear

The role of theory in the sciences

21

to be r11ajor differences betwee11 tl1ese two philosophers. Popper suggested tl1at, when two con1peting tl1eories present the111selves, scientists would choose tl1e better one, the one that is able to survive the most rigorot1s crucial tests. Kuhn rejected this notion of Popper's by proposing the view that shifts in paradigi115 are drastic and cause 1najor alterations of perception tl1at tnake agreen1ent on \IVhat constitutes a valid test i111possible. An essential ele1nent of a paradig111 is the theory, but Kuhn 1neant son1etl1ing broader. Included in the notio11 of paradigi11 are a scientific commt1nity's shared and accepted vision of the way things work, an agreed-upon set of problen1s or puzzles that provide scientists with the opportunity to conduct research, and agreed-upon rules and standards for the practice of science (Kuhn, 1996). Furthermore, Kuhn did not believe, as Popper did, that a better, deeper theory takes the place of one that fails to pass a falsifying test or that science proceeds by revolt1tionary changes that overtur11 existing theories. Instead, Kuhn suggested that when new theories are constructed to explain anomalies that cannot be accounted for by the existing theory, the new theories co111pete with one another for acceptance vvhile adherents to tl1e existing theory struggle to retain it. Tl1e salient sirnilarities a11d differences between Popper and Kul1n tnay be highlighted in the following vvay. Conjecture, test, a11d refutation are central ele111ents of Popper's views on how science vvorks. Tl1ese ele111ents are also a part of Kuhn's position, but only present during vvhat Kul1n (1.996) called 11or111al science - the work scientists do witlun the context of an existing a11d received paradign1. Popper gave a pro111inent place to conjecture, but n1aintai11ed that the introduction of a new conjecture is 11ot based on a given rationale. Atte111pts to £11sify the conjecture or hypothesis are, however. Kuhn argued sin1ilarly that the introduction of a new paradigi11 is not based on a given rationale but that scientists do 11ave rationales for the work they do within the paradign1; tl1at is, as tl1ey proceed vvith the tasks of nom1al science. The major difference between Popper and Kuhn concerns the nature of a scientific revolution or the 111an11er i11 which science moves or shifts fron1 one theory or paradigm to another. For Popper, the move is rational and logical; scientists accept the better theory, the one that withstands falsification. For Kuhn, the sllift is characterized by profou11d alterations of perception that give rise to nevv and different ways of seeing, of new and different scientific proble111s to solve, and of new and differe11t ways to solve those problems. When the paradigin shift is complete, 'the professio11 will have changed its view of the field, its 1nethods, and its goals' (Kuhn, 1996, p. 85). A fi1ndamental change in orientation and in the framework for normal science is tl1e result of tl1e paradigm sruft.

Theory in the human sciences W e now turn ot1r attention to the role oftheo1y in the hu1nan scie11ces a11d explore some of the differences between the physical and the hu1nan sciences, in tl1e empirical as well as the theoretical do1nains. Indeed, the two do11i