- TOWARD AN EVOLUTIONARY-DEVELOPMENTAL FRAMEWORK FOR PSYCHOPATHOLOGY
- The Missing Foundation of Developmental Psychopathology
- Evolutionary-Developmental Psychology
- Metatheoretical Foundations of EDP
- Developmental Systems Theory: An Alternative Metatheory?
- BEYOND PATHOLOGY: ADAPTATION, MALADAPTATION, AND DISORDERS
- What Is a Disorder?
- A Taxonomy of Undesirable Conditions
- Implications for the Core Points of Developmental Psychopathology
- BEYOND MENTAL HEALTH: CONDITIONAL ADAPTATION AND LIFE HISTORY THEORY
- Developmental Plasticity and Conditional Adaptation
- Adaptive Plasticity in the Development of Life History Strategies
- The Centrality of the Phenotype
- Implications for the Core Points of Developmental Psychopathology
- BEYOND ALLOSTATIC LOAD: THE STRESS RESPONSE SYSTEM AS A MECHANISM OF CONDITIONAL ADAPTATION
- The Adaptive Calibration Model
- ALM and ACM: A Comparison
- Implications for the Core Points of Developmental Psychopathology
- BEYOND DIATHESIS-STRESS: DIFFERENTIAL SUSCEPTIBILITY TO ENVIRONMENTAL INFLUENCES
- Differential Susceptibility: Orchids and Dandelions
- Evolutionary Models of Differential Susceptibility
- Differential Susceptibility as Adaptive Stochastic Variation
- Differential Susceptibility as a Model of OrganismāEnvironment Interplay: The Case of Pubertal Development
- Implications for the Core Points of Developmental Psychopathology
- BEYOND THE DSM: A LIFE HISTORY FRAMEWORK FOR MENTAL DISORDERS
- Limitations of Current Taxonomic Approaches
- A Life History Framework for Psychopathology
- Toward a Life History Taxonomy of Mental Disorders
- Implications for the Core Points of Developmental Psychopathology
- CONCLUSION
- REFERENCES
Since its inception in the 1970s and 1980s, the discipline of developmental psychopathology has pursued an ambitious project of theoretical integration. The grand vision of developmental psychopathology is that of a truly multidisciplinary approach to the complex interplay of biological, psychological, and social-contextual aspects of both normal and abnormal development (Cicchetti, 1990, 2006; Hinshaw, 2013). As testified by this volume, the project has been remarkably successful, generating an impressive amount of empirical work while maintaining a shared language and a common theoretical background.
In this chapter we argue thatādespite its achievementsādevelopmental psychopathology has yet to realize its full potential, and that its integrative power is limited by the lack of an adequate metatheory. We contend that developmental psychopathology has much to gain by embracing modern evolutionary theory, the unifying metatheory of the life and behavioral sciences. We then review a host of recent theoretical developments in the field of evolutionary-developmental psychology (EDP) that address the organization of individual differences, the nature of environmental risk, the role of early stress, the nature of gene-environment interactions, and many other critical issues. Together, these contributions paint the contours of an integrative theory of human development and provide a sophisticated evolutionary foundation for developmental psychopathology. We aim to show that, far from undermining the tenets of developmental psychopathology, the EDP-based framework we describe supports all its core principles while also extending them, clarifying their underlying logic, and connecting them at a deeper level than previously possible.
We begin the chapter by considering the role of evolutionary theory in developmental psychopathology. After reviewing the core points of the discipline and the historical reasons for its separation from mainstream evolutionary biology, we present the integrative approach of EDP and discuss its metatheoretical foundations. The basic concepts we introduce here provide a general introduction to evolutionary biology and the overarching background for the rest of the chapter. We also review the main tenets of developmental systems theory (DST; Griffiths & Gray, 2004; Oyama, Griffiths, & Gray, 2001), consider its potential role as an alternative metatheory, and conclude that EDP provides a suitable framework for developmental psychopathology.
The second section explores the interplay between adaptation and maladaptation in the origin of disorders. We build on the distinction between adaptive and desirable traits and discuss how the concept of disorder can be specified in evolutionary terms. We then broaden our view to explore the many ways evolutionary and developmental processesāboth adaptive and maladaptiveāmay result in undesirable outcomes at the individual level.
Next, we introduce the concepts of developmental plasticity and conditional adaptation. We discuss how organisms make use of environmental cues to adaptively match their phenotypes to their developmental context and the ways those processes can fail and result in maladaptive outcomes. We then present a nontechnical overview of life history theory, the dominant biological theory of conditional adaptation and a general framework for understanding the organization of individual differences in physiology, growth, and behavior. Drawing on life history concepts, we take a closer look at the multidimensional nature of environmental risk and examine the logic by which physical and social environmental factors shape and direct individual development.
The chapter then focuses on the central role of stress in the development of individual differences and psychopathology. We argue that the standard framework employed in developmental psychopathologyāthe allostatic load model (McEwen & Stellar, 1993)āfails to capture the multiple roles of stress in development, and promotes a limited understanding of stress as a risk factor and a source of physiological and behavioral dysregulation. As an alternative, we propose the adaptive calibration model (ACM; Del Giudice, Ellis, & Shirtcliff, 2011), a theory of individual differences in stress responsivity across the life span based on concepts from life history theory and the theory of conditional adaptation. The Adaptive Calibration Model offers a renewed understanding of the role of stress in development and illustrate the heuristic and integrative power of the evolutionary developmental approach.
People vary dramatically in the extent to which they respond to their developmental context. In recent years, it has become apparent that many of the genetic, temperamental, and neurobiological factors that make people more vulnerable to negative, stressful environments also make them more likely to benefit more from positive, supportive environments. Differential susceptibility to the environment is a source of systematic organism Ć environment interactions, with many implications for both normal and pathological development. We explore the evolutionary logic of differential susceptibility and review the main theoretical models that have been proposed to explain it (Belsky, 1997, 2005; Boyce & Ellis, 2005).
We conclude the chapter by showing how life history concepts provide the foundation for an integrative evolutionary approach to mental disorders (Del Giudice, 2014a, 2014b). The framework we outline is based on the idea that individual differences in life history strategy set the stage for the development of psychopathology. The resulting taxonomy offers a promising alternative to both the atheoretical approach of the Diagnostic and Statistical Manual and empirical classification systems based on the distinction between internalizing and externalizing disorders.
Each section in the chapter shows how an evolutionary developmental approach goes beyond current thinking and contributes to broaden our understanding of psychopathology. At the end of each section, we consider how the concepts and theories we discuss relate to the core points of developmental psychopathology. As our ultimate goal is to catalyze a paradigm shift in developmental psychopathology, we deliberately focus on general principles rather than specific disorders throughout the chapter.
Toward an Evolutionary-Developmental Framework for Psychopathology
The Missing Foundation of Developmental Psychopathology
Over the years, a consensus has formed around a set of core pointsāmethodological commitments, goals, and theoretical principlesāthat define developmental psychopathology as a scientific field. Developmental psychopathology adopts a multidisciplinary perspective; pursues integration across multiple levels of analysis; gives particular consideration to the social and cultural context, as well as to brain and neurobiological factors; and emphasizes person-centered designs in empirical research. Researchers in the field aim to describe, understand, and synthesize the interplay between normal and pathological development, between developmental continuity and discontinuity, and between risk and protective factors. Finally, developmental psychopathology adopts three key principles from systems theory and developmental biology: the twin principles of equifinality and multifinality, and a view of ontogenetic causality as probabilistic, nonlinear, and involving reciprocal interactions between the developing organism and the environment (see Cicchetti, 1990, 2006; Hinshaw, 2013).
These points are extremely valuable and we subscribe to all of them. At the same time, we recognize that something crucial is missing. Developmental processes are biological processes, and biology is ultimately about function. Yet while developmental psychopathology is highly attuned to the complexities of how humans develop, its core points are silent with respect to the whys of development. Why do developmental processes unfold in one way rather than another? Why, for example, have they evolved so as to be exquisitely sensitive to contextual factors? And why do different processes show different degrees of context sensitivity? More generally, what is development for? Nikolaas Tinbergen (1963) famously summarized the four types of explanation required for a complete understanding of a biological system. With an updated terminology, they can be described as mechanism (what is the system like? How does it work?); development (how does it come to be over developmental time, and how does it change across the life span?); phylogeny (what is the evolutionary history of the system? How did it change across generations and species?); and adaptation (why is the system the way it is? What selective advantages does it confer, or used to confer, to the organism?).
Developmental and mechanistic explanations concern the way an organism works in the present, without reference to evolution and adaptation; collectively, they are called proximate explanations. In contrast, ultimate explanations (phylogenetic and adaptationist) consider the organism in relation to its past and to the evolutionary forces that shaped its body and behavior (Mayr, 1963). The four types of explanation are not mutually exclusive but complementary and synergistic: adaptive function crucially informs the study of mechanism and development, while development and mechanism constrain the range of plausible adaptive explanations (see Scott-Phillips, Dickins, & West, 2011; ...
