Measuring the need for solitude in emerging adulthood: Development and validation of the Need for Solitude (NFS)...

The need for solitude is of increasing public interest now that individuals can be constantly connected with others through digital technology. Yet despite its timeliness, the need for solitude still lacks a valid conceptualisation and measure in our digital society. To address this gap, we conceptualise the need for solitude and develop a self-report measure to capture individual differences in need strength in two preregistered online survey studies among emerging adults (18-25-year-olds). In Study 1, we establish the 14 items and unidimensional structure of the Need for Solitude (NFS) scale (n_1a = 224) and confirm its structural validity, convergent validity, discriminant validity, internal consistency, and test-retest reliability (n_1b = 303) in student samples in the Netherlands. In Study 2, we replicate its psychometric properties and establish its measurement invariance in a community sample of emerging adults in the Netherlands and the United Kingdom (N = 841). Combined, the results suggest that the NFS is a distinct and measurable trait that aligns with but also deviates from conceptually related traits (e.g., loneliness). Overall, the NFS scale provides a robust foundation for studying individual differences in the need for solitude in our digital society.