Editorial: Variability and Individual Differences in Early Social Perception and Social Cognition

In this research topic, we showcase state-of-the-art research on the sources and meaning of variability and individual differences in early social perception and cognition. These papers demonstrate that such variability contributes to our understanding of early development, requires specific methodological toolboxes and skill sets to expand our developmental inventory, and relates to important abilities later in life. The first set of papers (Examining individual variability to elucidate developmental mechanisms and pathways) highlights the importance of focusing on individual variability (above and beyond group variability) for understanding the underlying mechanisms of early social cognition and how meaningful early differences relate to abilities later in childhood. Hepach et al. propose that studies of social cognition go beyond using a single behavioral measure (i.e., looking time) and offer two novel measures, pupil dilation and postural changes. They argue that these measures may provide insight into the mechanisms and motivations underlying behavioral responses (e.g., prosocial behaviors) in which there may be individual differences even if behavioral indices are similar at a group level. The other papers in this section use longitudinal research to investigate the meaning of measures of infant social cognitive development in the context of broader developmental trajectories. Gampe et al. found that infants' action perception and action production in a contralateral reach task improve consistently across the second half of the first year of life at a group level; however, infants' individual action production abilities were not correlated across time, and there was no consistent causal relation between action perception and production across age. Thus, this study of individual differences uncovers a dynamic link between action perception and production in the first year of life. Brink et al. investigate how infant social attention relates to preschool social cognition. They found that infants' habituation to a social display of intentional action was related to measures of infant social-interactive experiences and temperament and, later, preschool theory of mind. These studies highlight the role of both experience and temperament in predicting social cognitive abilities, as each factor was an independent predictor of preschool theory of mind ability. Adding to this work on the downstream consequences of social cognition in infancy, Kristen-Antonow et al. examine effects of early individual differences in social cognition on the developing sense of self. Infants' social responsiveness in a still-face paradigm predicted their later mirror-self-recognition, and their imitation abilities predicted later delayed-self-recognition. This work emphasizes the importance of measuring variability …