The Broad Autism Phenotype Predicts Relationship Outcomes in Previously Unfamiliar College Roommates

Background: Milder but qualitatively similar subclinical traits of autism known as the “broad autism phenotype” (BAP) have been associated with difficulties forming and maintaining quality relationships (Wainer et al., 2013). However, the process by which the BAP influences relationship outcomes remains unclear.   

Objectives: The current study examined how BAP traits in previously unfamiliar college roommates were associated with their interpersonal behaviors during relationship development and their relationship quality after several months of cohabitation. Social BAP traits (i.e., aloofness and pragmatic language abnormalities), but not nonsocial BAP traits (i.e., rigidity), were hypothesized to be associated with decreased relationship satisfaction and commitment to the relationship by the end of the study. Drawing upon Interpersonal Theory (Horowitz et al., 2006), the behaviors of warmth and dominance were hypothesized to mediate the effects of social BAP traits on relationship outcomes.   

Methods: Newly formed same-sex roommate dyads with limited to no previous familiarity (N = 160 individuals) were assessed every two weeks for 10 weeks. Participants initially completed the Broad Autism Phenotype Questionnaire (BAPQ), and subsequently reported on the warm and dominant behaviors exchanged within the dyad, as well as their overall relationship satisfaction and commitment at the end of the study.  

Results: We used Actor-Partner Interdependence Models (APIMs) to evaluate our hypotheses. An interaction of roommates’ aloof traits predicted relationship satisfaction, and simple slopes analyses revealed that low aloof participants were less satisfied with high aloof roommates (b = -.34 [95% CI: -.62, -.07], SE = .14, p = .016). Aloof traits were associated with both warmth (b = -.32, 95% CI [-.53, -.15], SE = .09, p < .001) and dominance (b = -.35, 95% CI [-.53, -.18] SE = .09, p < .001), with warmth mediating the effects of aloofness on relationship outcomes measured through indirect effects (i.e, ab). Participants’ aloofness predicted their own expressions of warmth, which subsequently predicted relationship satisfaction (ab = -.08, 95% CI [-.15, -.02], κ² = .17). Also, high aloof participants evoked less warm behaviors from roommates, which led participants to feel less satisfied (ab = -.16, 95% CI [-.26, -.07], κ² = .10) and less committed (ab = -.29, 95% CI [-.51, -.11], κ² = .07). Neither pragmatic language abnormalities nor rigidity were associated with mediators or outcomes.   

Conclusions: Aloof traits in unfamiliar roommates were associated with relationship quality after 10 weeks of cohabitation, with behaviors of warmth mediating some of these effects. Roommates more similar on aloof traits, including those both high on aloofness, were more satisfied, suggesting that compatibility on this BAP feature may be particularly relevant to relationship satisfaction. Despite constituting an additional social BAP trait, pragmatic language abnormalities were not associated with relationship satisfaction. This suggests that not all social BAP traits are equally predictive of relationship outcomes, with social motivation (aloofness) more predictive than social competence (pragmatic language abnormalities).