What a picture selection task can tell us about scalar implicature processing? A neuroimaging investigation

Pragmatic inferences beyond the literal meaning of utterances occur with weak scalar expressions, such as 'some', which has a logical meaning of 'some and possibly all' and a pragmatic meaning of 'some but not all', derived through a scalar implicature (SI). Such processing is assumed to involve linguistic and extra-linguistic processes, including Theory of Mind and executive functions. Previous neuroimaging studies used truth value evaluation tasks to study SI processing, showing involvement of the left inferior frontal gyrus (IFG), left anterior middle frontal gyrus (MFG) and medial frontal gyrus (MeFG)/anterior cingulate cortex (ACC). This study used a picture selection task to better understand the role of these regions in SI processing. A region of interest analysis showed differences between a condition that promoted an implicature (with a weak scalar expression) and a condition that did not (with a strong scalar expression) only in the MeFG/ACC, also identified in a complementary whole-brain analysis (together with posterior activations). Based on the differences between processes related to truth value evaluation tasks and picture selection tasks, we propose that the IFG is linked to access to alternatives, the anterior MFG is associated with response-related processing, and the MeFG/ACC is associated with Theory of Mind.This article is part of the theme issue 'At the heart of human communication: new views on the complex relationship between pragmatics and Theory of Mind'.