An interdisciplinary linked-lives approach to individual differences in social behaviour

Individuals differ considerably in their social behaviour. Recently, various behavioural sciences have begun to acknowledge the systematic nature and high relevance of this individuality, but approaches from different disciplines are currently isolated from each other. We propose an integrative, interdisciplinary approach for a more comprehensive understanding of individuality in social behaviour, considering (1) features ('What kinds of individual differences exist?'), (2) sources ('How do these differences emerge within individuals' social environments?'), and (3) outcomes ('What are the consequences of these differences, and how can relevant outcomes be changed through tailored interventions?'). We highlight common insights across disciplines, key challenges stemming from discipline-specific approaches, and new potentials enabled through the interdisciplinary approach. By allowing comparative analyses across species, groups of individuals, and contexts, our approach promises to uncover the shared and unique nature of individuality in human social behaviour. We offer concrete recommendations to guide the implementation of the interdisciplinary approach.