Online pragmatic interpretations of scalar adjectives are affected by perceived speaker reliability.

Linguistic communication requires understanding of words in relation to their context. Among various aspects of context, one that has received relatively little attention until recently is the speakers themselves. We asked whether comprehenders' online language comprehension is affected by the perceived reliability with which a speaker formulates pragmatically well-formed utterances. In two eye-tracking experiments, we conceptually replicated and extended a seminal work by Grodner and Sedivy (2011). A between-participant manipulation was used to control reliability with which a speaker follows implicit pragmatic conventions (e.g., using a scalar adjective in accordance with contextual contrast). Experiment 1 replicated Grodner and Sedivy's finding that contrastive inference in response to scalar adjectives was suspended when both the spoken input and the instructions provided evidence of the speaker's (un)reliability: For speech from the reliable speaker, comprehenders exhibited the early fixations attributable to a contextually-situated, contrastive interpretation of a scalar adjective. In contrast, for speech from the unreliable speaker, comprehenders did not exhibit such early fixations. Experiment 2 provided novel evidence of the reliability effect in the absence of explicit instructions. In both experiments, the effects emerged in the earliest expected time window given the stimuli sentence structure. The results suggest that real-time interpretations of spoken language are optimized in the context of a speaker identity, characteristics of which are extrapolated across utterances.