Beyond the Core-Deficit Hypothesis in Developmental Disorders

Abstract

Developmental disorders and childhood learning difficulties encompass complex constellations of relative strengths and weaknesses across multiple aspects of learning, cognition, and behavior. Historically, debate in developmental psychology has been focused largely on the existence and nature of core deficits-the shared mechanistic origin from which all observed profiles within a diagnostic category emerge. The pitfalls of this theoretical approach have been articulated multiple times, but reductionist, core-deficit accounts remain remarkably prevalent. They persist because developmental science still follows the methodological template that accompanies core-deficit theories-highly selective samples, case-control designs, and voxel-wise neuroimaging methods. Fully moving beyond "core-deficit" thinking will require more than identifying its theoretical flaws. It will require a wholesale rethink about the way we design, collect, and analyze developmental data.

Keywords: cognitive development; developmental disorders; developmental psychology; developmental science.

Fig. 1.

Distributions of children within a simple artificial neural network trained on data from 530 children taken from the Centre for Attention, Learning and Memory (CALM) sample (Holmes, Bryant, the CALM Team, & Gathercole, 2019). Each node represents a profile learned by the algorithm, with spatially nearby nodes having more similar profiles. Therefore, the maps represent the multidimensional spaces that reflect the performance differences across the children. The left-most panel shows the best-matching unit for all children, and the subsequent panels show those for children with different diagnoses. The training data set included measures of fluid reasoning, vocabulary, verbal and spatial short-term and working memory, and phonological awareness (see also Astle, Bathelt, The CALM Team, & Holmes, 2019). ADHD = attention-deficit/hyperactivity disorder; ASD = autism spectrum disorder.