The Social Motivation Theory of Autism

The idea that social motivation deficits play a central role in Autism Spectrum Disorders (ASD) has recently gained increased interest. This constitutes a shift in autism research, which has traditionally focused more intensely on cognitive impairments, such as theory-of-mind deficits or executive dysfunction, and has granted comparatively less attention to motivational factors. This review delineates the concept of social motivation and capitalizes on recent findings in several research areas to provide an integrated account of social motivation at the behavioral, biological and evolutionary levels. We conclude that ASD can be construed as an extreme case of diminished social motivation and, as such, provides a powerful model to understand humans’ intrinsic drive to seek acceptance and avoid rejection. Social motivation and social cognition: two competing accounts of autism Over the past three decades, a number of theories have been put forward to account for the pervasive social impairments found in Autism Spectrum Disorders (ASD). Among the various attempts, the idea of a core deficit in social cognition (theory of mind, or ToM, in particular; see Glossary) has become one of the most prominent accounts of ASD. Concomitantly, the impact of motivational factors on the development of social skills and social cognition has received little attention. Recently, however, social motivation has emerged as a promising research domain at the intersection of social psychology, behavioral economics, social neuroscience and evolutionary biology. In this review, we integrate these diverse strands of research and defend the idea that social motivation is a powerful force guiding human behavior and that disruption of social motivational mechanisms may constitute a primary deficit in autism. In this framework, motivational deficits are thought to have downstream effects on the development of social cognition, and deficits in social cognition are therefore construed as a consequence, rather than a cause, of disrupted social interest. Providing a complete account of social motivation requires both proximate and ultimate explanations. Proximate explanations pertain to how a behavior functions and ultimate explanations to why it was selected by evolution. At the proximal level, social motivation can be described as a set of psychological dispositions and biological mechanisms biasing the individual to preferentially orient to the social world (social orienting), to seek and take pleasure in social interactions (social reward), and to work to foster and maintain social bonds (social maintaining). At the ultimate level, social motivation constitutes an evolutionary adaptation geared towards enhancing the individual’s fitness in collaborative environments (see Figure 1). We first present evidence supporting this integrated model of social motivation in healthy individuals, and proceed to review behavioral manifestations of diminished social orienting, social reward and social maintaining in ASD and the associated disruptions in the neural circuitry that typically underlie these behaviors. We then demonstrate that, as predicted by the evolutionary framework, some areas of social functioning are preserved in ASD. We conclude by arguing that deficits in social cognition are better explained within a social motivation framework, and acknowledge the limits of both socio-cognitive and social motivation theories in accounting for non-social deficits in ASD.