Fiscal Year
FY 2025
April 2025 – March 2026

Principal Investigator
Sachiko Kiyama
Associate Professor, Graduate School of Arts and Letters

Co-Investigators
Masatoshi Koizumi
Professor, Graduate School of Arts and Letters

Research Keywords
Indirect intention understanding ; ASD ; Cognitive probe task

1. Research Overview

Appropriate exchange of intentions with others is essential for social life, and major misunderstandings can impair it. Autism spectrum disorder (ASD), reported to affect about 3% of the Japanese population, is a neurodevelopmental condition characterized by difficulties in social communication. Even when literal language comprehension is intact, individuals with ASD often have difficulty recognizing intentions in line with context and interpersonal relationships. This project aims to clarify the cognitive processes underlying the understanding of indirect speech in individuals with ASD, including how they differ from typically developing (TD) individuals and how they vary among individuals with ASD.

In this project, we developed a Japanese version of the cognitive probe task (Holtgraves, 2001), which uses response times to examine the degree of reliance on gist memory. We first (1) compared younger and older TD adults, and then (2) compared young to middle-aged adults with ASD and TD adults. (1) The comparison between younger (n = 34) and older (n = 34) TD adults showed that older adults recognized the intentions of indirect speech more automatically than younger adults, suggesting that older adults actively use gist representations, which have high adaptive value. (2) The comparison between adults with ASD (n = 29) and TD adults (n = 26) suggested that automatic recognition of indirect speech is weaker in the ASD group than in the TD group. Differences were also found in how time was allocated to intermediate stages of comprehension before reaching final understanding, suggesting differences in comprehension strategies. Furthermore, within the ASD group, automatic recognition of indirect speech was more suppressed in those with higher intelligence, whereas it occurred more readily in those with better subjective interoception. These findings suggest that interoception is involved in gist-based recognition of indirect speech in individuals with ASD.

2. Significance of the Research and Future Prospects

By clarifying how interoception—the foundation of human emotion—affects language comprehension, this study constitutes important basic research for the pursuit of “human-like AI.” The question of whether AI can respond appropriately to human emotions has already been examined; building on such work, a more detailed, multifaceted examination of the diversity of human language comprehension processes, centered on intelligence and interoception, can yield knowledge through which the humanities and social sciences contribute to the So-Go-Chi (convergence knowledge) project.

3. Conclusion

Autism spectrum disorder (ASD) is characterized by difficulties in interpersonal communication, and even when literal language comprehension is intact, individuals with ASD often have difficulty recognizing intentions in line with context and interpersonal relationships. This project aims to clarify the cognitive processes underlying the understanding of indirect speech in individuals with ASD in comparison with typically developing (TD) individuals. We administered a cognitive probe task, which uses response times to examine how readily indirect speech is recognized, to (1) younger and older TD adults and (2) adults with ASD and TD adults. The results showed that (1) older TD adults recognized the intentions of indirect speech more automatically than younger adults, and (2) automatic recognition of indirect speech was weaker in the ASD group than in the TD group, suggesting that interoception is involved in gist-based recognition of indirect speech.