At age 17, twins completed the Family Environment Scale (FES; Moos & Moos, 1986) which contains 90 items that tap different aspects of family life (e.g., time spent together; help and support of each other; strictness of rules; focus on achievement). Items were rated on a 4-point scale (anchored at “definitely true” and “definitely false”). Based on prior literature on family factors related to psychopathic traits, the Cohesion and Support scales from the FES were used to characterize the extent to which family members were close (e.g., had feelings of togetherness; spent time together) and supported one another (e.g., backed each other up; helped each other), respectively. Higher scores on each scale indicate higher levels of each characteristic. Twins also completed the FACES III (Olson, Porther, & Lavee, 1985) measure at age 17, which also assesses family functioning. There are 20 items rated on a 5-point scale (1 = Almost never; 5 = Almost always) that tap adaptability and cohesion facets of family environment. The Cohesion scale was used as an additional measure of that dimension and contained item regarding helpfulness of family members and togetherness.
