Understanding Developmental Disorders

John Morton is the former Director of the Medical Research Council’s Cognitive Development Unit. He is now Visiting Professor in the Department of Psychology and Honorary Fellow of the Institute of Cognitive Neuroscience, University College London.

Preface and Acknowledgements viii

Chapter 1 Introducing Cause 1

Cause and public issues 1

Cause and individual events: ‘Why did Romeo die?’ 6

Some more reasons for not looking at individual cases 9

The need for a framework for thinking in 10

Creating a tool: the problem of notation 14

An example of the limits of language 15

An invitation to consider diagrams as a tool 18

A tool for representing causal relationships 18

Chapter 2 Introducing Cognition 20

One thing I do want you to believe 20

Reductionism 22

Can we rely on behaviour? 24

The IQ example: a note of caution 27

Why cause needs cognition 29

Chapter 3 Representing Causal Relationships: Technical and Formal Considerations 34

Categorizing facts 34

The causal notation 38

Starting a causal model for autism 41

Complications 46

Some easy stuff on cause and correlation 51

Other notations 54

Chapter 4 Autism: How Causal Modelling Started 67

The biological origin of autism 74

The role of cognition in defining autism 81

What is mentalizing? 86

The non-social features of autism: how to diagram ideas on weak central coherence in autism 89

Summary 92

Chapter 5 The What and the How 98

Ground rules of causal modelling 99

Chapter 6 Competing Causal Accounts of Autism 106

Representing the effects of environmental factors 107

Cognitive theories of autism 112

Chapter 7 The Problem of Diagnosis 133

Diagnosis and cause: relying on behaviour 134

The Spanish Inquisition example: the dangers of labelling 135

Problems of diagnostic practice 140

Variability 148

Changes over time: improvement and deterioration 152

The variability of the phenotype 153

On co-morbidity and the question of residual normality 158

To summarize 160

Chapter 8 A Causal Analysis of Dyslexia 161

The dyslexia debate: Is there such a thing as dyslexia? 161

The discrepancy definition of specific reading disability 164

Towards a cognitive definition 166

An X-type causal model of dyslexia 168

Competing theories of dyslexia 176

Non-biological causes 195

Other biological causes of reading failure 199

How do we sort among the options? 200

The relationship between acquired and developmental dyslexia 204

A theoretical update 204

Chapter 9 The Hyperkinetic Confusions 208

Drugs as diagnostic refinement 212

Types of theory 216

The problem of co-morbidity: conduct disorder and ADHD 218

The cognitive level 219

Sonuga-Barke’s dual pathway model 223

Summary 226

Chapter 10 Theories of Conduct Disorder 227

The violence inhibition mechanism (VIM) model 228

The social information processing model for aggressive children 231

The coercive parenting model of Patterson 235

The theory of life-course persistent antisocial behaviour 236

What does the application of the framework tell us about the theories? 244

Chapter 11 Tying in Biology 247

Relations between the cognitive and biological levels 247

Equivalence: brain to cognition 251

Causal influences from cognition to brain 253

Genes and cause: the end of behaviour genetics 255

Endophenotypes 264

Mouse (and other) models for human disorders 266

Chapter 12 To Conclude 270

References 273

Name Index 292

Subject Index 296