The role of linguistic speaker identity on language credibility: Evidence from a written modality paradigm

General knowledge (audio presented) statements that are unknown (“Ants don’t sleep”) are often judged as less credible when produced by foreign speakers compared to native speakers. In addition, (written presented) under-informative statements (“Some dogs are mammals”) that can give rise to a scalar implicature are more acceptable when associated to a foreign-accent than to a native speaker. According to one interpretation, different expectations about the speech of foreign speakers would determine these effects (non-native speech is associated with more grammatical and semantic errors). A second interpretation argues that the intelligibility of native and foreign accent speech involves different processing loads in the listeners, influencing the judgment of the statement. Here we test the role of expectations about foreign-accented statements when the accent itself of the speakers cannot be perceived because the modality of presentation is written. In 2 experiments, 200 Italian native participants read a bio description of two persons (an Italian and a foreign-accent speaker). Four types of statements were presented: Unknown true statements; Under-informative statements; and two filler conditions, true and false statements. Half of the statements were associated to each speaker. Participants rated how much each statement makes sense on a five-point scale. Results showed more acceptable judgments in Unknow and Under-informative statements when associated to the foreign speaker. These results were replicated in two new experiments combining speaker’s face pictures to the bio description. In line with the account of expectations, our results suggest that the speaker's linguistic identity modulates the listeners judgments of the statements.