Aging with Elevated Autistic Traits: Theory of Mind Performance in Younger and Older Adults.

Background: Associations between the presence of autistic traits and theory of mind (ToM) ability have been demonstrated among autistic and non-autistic young adults. Poorer ToM ability has also been observed with typical aging but has seldom been examined across the adult lifespan in relation to elevated autistic traits.

Objectives: This study will explore differences in ToM performance among younger and older adults with/without elevated autistic traits.

Methods: 96 adults (Younger: n=49 aged 18-46; Older: n=47 aged 60-91) completed the Strange Stories Film Task (SSFT) and Frith-Happé Triangle Animations (TA) to measure ToM ability. The SSFT reflects real-world scenarios and produces three scales related to ToM performance (Intention, Interaction, Mental State speech) and one memory scale. The TA task uses dynamic silent animations and produces three scales related to ToM performance (Appropriateness, Interaction and Mental State speech). The Broad Autism Phenotype Questionnaire (BAPQ) measured the level of autistic traits based on self-report. Individuals were divided based on age (Younger vs. Older), and as being below or above the clinical cut-off for elevated autistic traits on the BAPQ (non-BAP vs. BAP).

Results: A 2x2 ANOVA examined the effects of age and autistic traits. For the SSFT, results showed a main effect of autistic traits on all three ToM scales, with non-BAP demonstrating better performance than BAP. No significant age-effects or interactions were observed. However, SSFT Interaction score showed a non-significant trend towards an interaction, with Older non-BAP adults performing better than Older BAP adults. For the memory scale, both autistic traits and age-effects were observed (non-BAP better than BAP; Younger better than Older) but the interaction did not reach significance. For the TA task, results revealed main effects of autistic traits and age on the Intentionality scale (non-BAP better than BAP; Younger better than Older). An interaction of autistic traits and age was also observed in Intentionality, with Older non-BAP adults performing better than Older BAP adults. No other significant main effects or interaction of autistic traits or age were observed on the TA task.

Conclusions: Results suggest that across adulthood, individuals with elevated autistic traits show poorer performance on ToM tasks. Few age-effects were observed in this study. Despite difficulties in ToM performance being common in later-life, this effect was not observed when using a ToM task designed to reflect real-world scenarios. This suggests that age-decrements in ToM may be exacerbated by non-social task characteristics. However, a significant interaction and a non-significant trend were observed in some aspects of ToM performance, suggesting that age and autistic traits could confer a compounded risk to ToM performance in older adults who endorse elevated autistic traits. Future studies should examine whether tests designed to reflect real-world scenarios are associated with behaviour in the real-world, and further explore whether elevated autistic traits in later-life form a compounded risk to ToM performance.