LAUSR

INTRODUCTION Motivation is an overlooked but crucial factor in determining whether solitude is psychologically beneficial or risky. This paper describes the development and validation of the Motivation for Solitude Scale - Short-Form (MSS-SF), a measure grounded in Self-Determination Theory that differentiates between intrinsic versus extrinsic motivations for solitude. METHODS Emerging adult (N = 803) and adolescent (N = 176) participants were recruited in four successive samples from the United States for the purposes of scale development and validation. Participants completed an on-line survey that included the MSS-SF and various well-being and personality measures. RESULTS & CONCLUSIONS Confirmatory Factor Analyses resulted in a two-factor solution, selfdetermined solitude (SDS) and not self-determined solitude (NSDS), and showed the MSS-SF to be reliable with adolescents and emerging adults, with satisfactory convergent and discriminant validity. Engaging in solitude for extrinsic, not self-determined reasons was associated with loneliness, social anxiety, and depressive symptomatology; in contrast, solitude chosen for intrinsic, self-determined reasons was positively correlated with well-being, for emerging adults in particular. The MSS-SF goes beyond preference for solitude to distinguish two distinctly different motivations for solitude, and in so doing, allows researchers to better understand the affordances and risks of being alone for adolescents and emerging adults.