The Content and Function of Interests in the Broad Autism Phenotype

Background: Many recent studies have demonstrated that the social features of ASD can be found in qualitatively similar but milder forms in members of the general population with the Broad Autism Phenotype (BAP). Less clear is whether individuals with the BAP are also characterized by non-social features of ASD, such as “circumscribed interests” (CI), defined by an intense preoccupation within a narrow range of topics.

Objectives: This study compared the content and function of interests between adults with and without the BAP. We predicted that individuals classified as having the BAP would report greater interest in hobbies related to common CIs found in ASD (e.g., video games) compared to those without the BAP, and that the hobbies they endorsed would be more limited in range (i.e., more circumscribed) but pursued with greater intensity (i.e., time per hobby).

Methods: Seventy-four undergraduates (59% female; Mean Age: 22.81) completed the Broad Autism Phenotype Questionnaire (BAPQ), an interest survey, and a computerized task in which images related to various interests were rated on valence (i.e., pleasure) and arousal (i.e., excitement). Both the survey and the ratings task consisted of content related to common CI previously reported for individuals with ASD, as well as control content (i.e., interests not disproportionately prevalent in ASD).  

Results: Twenty-eight participants were classified as “BAP-positive” by exceeding the gender-specific self-report cutoff score on the BAPQ (Sasson et al., 2013). On the ratings task, a repeated-measures ANOVA with BAP-status and gender as the between-group variables, and image-type (ASD vs non-ASD interests) as the within-group variable, produced a significant group x object type interaction for both valence (F(1,69)=18.41, p<.001) and arousal (F(1,69)=7.56, p=.007). Post-hoc tests showed that these interactions were driven by BAP-positive individuals having lower valence ratings of images related to non-ASD interests (t(71)=2.45, p=.015), and higher arousal ratings of images related to ASD interests (t(71)=2.17, p=.033). On the survey, BAP-positive individuals endorsed fewer hobbies than BAP-negative individuals (p=.049), but the groups did not differ in the intensity in which hobbies were pursued. Compared to BAP-negative individuals, BAP-positive individuals reported significantly lower interest in exercising, playing sports, watching sports, running/biking, hunting/fishing, and studying religion, but significantly higher interest in programming, reading fiction, using phone apps/games, and a trend towards greater interest in computer games. Although many gender differences emerged on both the ratings task and the interest survey, they largely did not interact with BAP status.  

Conclusions: Across multiple measures, adults classified as having the BAP differed in their interests from those classified as not having the BAP. Those with the BAP rated images related to interests common in ASD as more exciting, and those related to interests less common in ASD as less pleasurable. They also self-reported fewer interests overall, with lower interest in many outdoor activities and sports (both playing and watching) but greater interest in some solitary (e.g., reading) and technology-related areas (e.g., computers). These findings suggest that many of the differences in the content and function of interests previously reported in ASD may extend to the BAP.