“…Personality traits were assessed using the parent report version of the Hierarchical Personality Inventory for Children (HiPIC; Mervielde & De Fruyt, 1999). This 144-item observer-based inventory has been deemed suitable for personality assessment in children and adolescents (Shiner & Caspi, 2003), and repeatedly provides valid and reliable measurements (Mervielde & De Fruyt, 2002;Watt, Hopkinson, Costello, & Roodenburg, 2016), including in Norway (Vollrath, Hampson, & Torgersen, 2016). The HiPIC has concurrent validity with the NEO PI-R (De Fruyt, Mervielde, Hoekstra, & Rolland, 2000) and yields dimension scores for traits that closely resemble the FFM (see Supporting Information for details on the HiPIC); imagination (corresponding to openness), benevolence (similar to agreeableness), emotional stability (corresponding to low neuroticism), conscientiousness, and extraversion.…”