Expertise modifies neural responses to causal inference during language comprehension

Linguistic communication demands a shared understanding, yet individuals within a community possess specialized semantic knowledge. Physicians, for instance, amass extensive knowledge about the origins of illnesses. A pertinent question arises: does such causal expertise impact the neural mechanisms underlying language comprehension?

To investigate, researchers compared medical experts and matched controls while they read two-sentence vignettes intended to evoke implicit causal inferences about illness or object mechanics. Control vignettes lacked such causal inferences. All vignettes were linguistically equivalent and comprehensible to both experts and non-experts.

When scrutinizing both groups, causal vignettes centered on illness engaged a temporoparietal semantic network previously associated with animates, i.e., people and animals. Conversely, causal vignettes concerning object mechanics activated a semantic network linked to places and objects.

Significantly, physicians demonstrated a more pronounced and consistent response in the animacy network, implying the utilization of a more extensive semantic knowledge base. This expertise effect was confined to biological inferences, not mechanical or mental state inferences. In contrast, isolated frontotemporal language and frontoparietal reasoning networks did not exhibit a preference for causally connected sentences or show expertise-related effects.

These results indicate that causal expertise modifies neural responses to causal inferences that occur spontaneously during language comprehension.