Implicit Theory of Mind (ToM) plays a key role in pragmatic reasoning of scalar implicatures

This study assessed the effect of explicit and implicit Theory of Mind (ToM) on pragmatic reasoning, specifically scalar implicature interpretation, in adult participants. We aimed to clarify whether different types of mentalistic content (explicit vs. implicit) selectively influence pragmatic inference processes.

Two within-subject experiments were conducted (N = 111, N = 120) using explicit, implicit (belief, desire, emotion, intention), and non-mentalistic stimuli prior to a scalar implicature sentence verification task. Reaction times (RT) were measured.

Significant increases in RT were observed specifically following implicit belief-related ToM stimuli. Explicit ToM stimuli and other implicit content (desire, emotion, intention) did not produce comparable effects.

Results support post-Gricean theoretical approaches, particularly relevance theory, highlighting the cognitive specificity of implicit belief attribution in scalar implicature processing. Findings underscore the importance of implicit ToM, especially belief reasoning, as a selective mechanism underlying pragmatic inference. These findings provide partial confirmatory evidence for the role of implicit ToM in pragmatic reasoning and offer exploratory insights into differences across ToM subcomponents, which require further replication.