Chapter 2 explores the rise of the English Improving Access to Psychological Therapies (IAPT) programme. This flagship initiative aimed at doing exactly what its titles suggests, and has drawn international acclaim – alongside critique and concern. In attending to its underpinnings, I highlight the managerial and clinical trends IAPT drew from and extended to proliferate therapy at scale. I examine how features of IAPT understood to be novel came to be regarded as vital forms of infrastructure around which other psychological services should be built. I also illustrate how the economic logics that underpinned IAPT initially resulted in particular kinds of therapy being rolled out for certain types of conditions experienced by specific groups; most notably, CBT for anxiety and depression diagnosed in adults of working age. The chapter reflects on the ramifications of IAPT, including in relation to the understandings of the nature of ill-health that result from it.

In Chapter 1, I demonstrate how professional claims-making operates as a form of boundary work that both configures and is configured by the evolving identity of clinical psychology. The keenness of many in the field to position it as different from psychiatry is illuminated, with the ‘diagnostic’ approach deemed particularly problematic by many leading clinical psychologists. Likewise, I spotlight how some in clinical psychology also labour to differentiate it from other psychological traditions (like counselling psychology and health psychology). This includes through the development of a professional body solely for clinical psychologists: the Association of Clinical Psychologists UK (ACP-UK). Ultimately, these forms of boundary-work help to configure the nature and practices of clinical psychology. Accordingly, they also have implications for the values and perspectives of individual therapists, and the kinds of care that patients are (not) able to access.

Chapter 1 establishes the foundational concepts of neuroimaging by exploring the complex relationship between brain structure and mental function. It traces the historical progression from ancient surgical approaches to modern noninvasive techniques, contextualizing how technological innovations have transformed our understanding of neural processes. The chapter examines the multiscale nature of brain investigation, from single-neuron recordings to population-level measurements, and evaluates the critical tradeoffs between spatial and temporal resolution across imaging modalities. Key neurophysiological principles underlying these technologies are introduced, including neuronal action potentials, hemodynamic responses, and the chemical processes that support neural activity. The text challenges common neuromyths while addressing fundamental questions about functional organization, from modular specialization to distributed network processing. By comparing the relative strengths and limitations of major neuroimaging tools (fMRI, EEG, MEG, PET, and TMS), the chapter provides an analytical framework for understanding how these methodologies collectively advance our ability to correlate brain activity with cognitive and behavioral processes, setting the stage for more detailed exploration in subsequent chapters.

Chapter 4 analyses how clinical psychologists preface (potential) care through negotiations of referrals and acts of assessment prior to any kind of therapy. I regard these as key ‘uncertainty moments’ in which practitioners must decide whether to see a patient for therapy. This decision-making process depends on far more than an ‘objective’ evaluation of the patient in front of them. Resolution of uncertainty entails the reciprocal configuration of at least three kinds of ontologies: the ontology of a potential patient, the ontology of the service in which they work, and the ontology of their profession. These are not necessarily stable; rather, they can be remade over time and in relation to particular service users (demonstrating how visions and adjudications of therapeutic need are highly contextualised). Such ‘prefacing practices’ contribute to the denial of access for some patients, although even exclusions might themselves sometimes be accounted for by professionals as forms of care.

In this Introduction, I sketch out the rise of a transnational ethic of access to treatments for ill-health, and how it configures and is configured by mental healthcare in the UK. The instantiation of this ethic has resulted in policy and clinical attention to enhancing access to psychological therapy (often cognitive behavioural therapy, CBT, specifically). I introduce the importance of clinical psychology within this context and chart its consolidation as a profession, alongside a discussion of the role of CBT within the UK. I also discuss the wider entanglements of psychological praxis and societies, and the theoretical perspectives that propel the analysis presented in this book. I conclude with outlining the various chapters that follow.

This chapter tackles positron emission tomography (PET), a functional neuroimaging technique that revolutionized brain imaging in the 1970s by providing the first colorful maps of brain activity. Beginning with its historical development from Hans Berger’s early hemodynamic measurements to modern scanners, the chapter examines how PET visualizes metabolic processes by tracking radioactively labeled tracers in the bloodstream. Unlike structural imaging methods, PET detects gamma rays emitted when positrons from the radiotracer collide with electrons, allowing researchers to measure regional changes in blood flow, glucose metabolism, and neurotransmitter activity related to cognitive processes. The chapter details practical aspects of PET studies, including experimental design, data acquisition, image reconstruction techniques, and visualization methods like subtraction analysis for mapping task-related brain activity. While MRI-based techniques have supplanted PET for many cognitive neuroscience applications, PET remains invaluable for certain investigations due to its unique ability to label diverse compounds, particularly for studying neuropsychiatric disorders, neurotransmitter systems, and metabolic processes in diseases like Alzheimer’s and epilepsy.

The chapter investigates the persuasiveness of moral rhetoric, that is, effects on nonsupporters of the party. Based on insights from previous work, I develop theoretical expectations that suggest that moral rhetoric is unlikely to be persuasive, or make nonsupporters see the party more favorably. Previous studies on moral persuasion suggest moral-value alignment between a moral message and the recipient can make the message persuasive. Yet previous work on attitudinal bias suggest that moral rhetoric may be unpersuasive regardless of moral alignment and even further alienate nonsupporters with negative preexisting attitudes. I test the hypotheses using experiments in Britain. I find that moral rhetoric does not easily convince nonsupporters. However, moral rhetoric can be quite persuasive when the message is strong and the party has moral credibility. Under those conditions, moral rhetoric increases favorable attitudes, on average and among nonsupporters who prioritize the moral intuition in the message. There is no evidence that moral rhetoric further alienates hostile nonsupporters. The findings present a rather optimistic picture about the persuasiveness of moral rhetoric.

Chapter 7 deals with neuroimaging methods for investigating the structural components underlying brain function. Beginning with lesion-symptom mapping (LSM), which identifies relationships between localized brain damage and specific cognitive deficits, the chapter examines how structural abnormalities correlate with functional impairments. Three primary approaches to measuring brain structures with MRI are discussed: structure tracing for hypothesis-driven volumetric analysis, voxel-based morphometry (VBM) for whole-brain comparison of tissue concentration, and surface-based morphometry (SBM) for analyzing the cortical sheet’s unique properties including thickness, curvature, and gyrification. The chapter then explores diffusion tensor imaging (DTI), a technique that visualizes white-matter tracts by measuring the anisotropic diffusion of water molecules along axon bundles. DTI tractography reveals the brain’s “highways,” short, intermediate, and long-range fiber pathways that connect functional modules within and across hemispheres. Together, these complementary techniques provide critical insights into the structural architecture supporting brain networks, offering a more complete understanding of brain organization when combined with functional imaging methods.

Chapter 9 introduces transcranial magnetic stimulation (TMS), a neurostimulation technique that uses rapidly changing magnetic fields to induce electric currents in targeted brain regions. Beginning with its historical roots in 19th-century electromagnetic experiments and evolving through Anthony Barker’s groundbreaking 1985 demonstration, TMS has become a critical tool for establishing causal relationships between brain activity and behavior. Unlike neuroimaging methods that only observe brain activity, TMS can temporarily interrupt or enhance neural processing, enabling researchers to create “virtual lesions” and directly test hypotheses about regional brain function. The chapter examines TMS delivery methods, single-pulse, paired-pulse, and repetitive stimulation, and their differential effects on cortical excitability. It details four primary research applications: virtual lesions for establishing causality, chronometry for determining processing timelines, mapping functional connectivity between brain regions, and tracking neuroplasticity. Clinical applications are discussed, particularly for treating depression and presurgical mapping. The chapter also addresses practical aspects of TMS implementation, localization techniques, and safety considerations, concluding with a brief overview of transcranial direct current stimulation (tDCS) as a milder alternative stimulation approach.