Abstract
BACKGROUND: Altruistic cooperation (AC) is essential in human social interactions. Previous studies have investigated AC-related behavior in children with autism spectrum disorder (ASD), revealing that there is considerable individual variability in the behavior. However, this issue is still largely unexplored especially in the adult population. AIMS: To investigate individual differences in AC-related behavior, we conducted the resource allocation task (RAT) and modified version of the ultimatum game (mUG) among adults with and without ASD. METHODS AND PROCEDURES: The study employed a cross-sectional design, involving 27 adults with ASD (mean age 29.1 ± 4.3 years; three females) and 27 adults with typical development (TD) (mean age 25.8 ± 6.7 years; two females), who completed the RAT and mUG tasks. Beyond clinical characteristics, we assessed three primary psychological metrics: the interpersonal reactivity index (IRI), Barratt impulsiveness scale, and the behavioral inhibition and activation systems. OUTCOMES AND RESULTS: No significant differences were observed in the proportions of participants with high AC when assessed by RAT (p = 0.15) and mUG (p = 0.59) between the TD and ASD groups. Participants with high AC from the RAT demonstrated higher perspective-taking scores on the IRI than those with low AC within both the TD (p = 0.04) and ASD groups (p = 0.03). In the TD group, high AC individuals also scored higher on the IRI's fantasy subscale as per the mUG (p = 0.03); however, this trend was not present in the ASD group. CONCLUSIONS AND IMPLICATIONS: The present findings indicate that empathy plays an important role in individual differences in AC-related behavior among adults with and without ASD, although the role could be different depending on the types of AC-related behavior between TD and ASD populations.