People do not engage in ad-hoc reasoning about alternative messages when interacting with a literal speaker

Derivation of pragmatic inferences typically assumes that both interlocutors behave rationally, as described by the cooperative principle. However, real-world communication often involves speakers who cannot behave fully rationally due to factors such as limited language proficiency, high cognitive load, or insufficient reasoning skills. In such cases, listeners may adjust their inferences to account for the speaker's limitations. In this study, we investigate whether participants engage in ad-hoc reasoning about alternative messages available to the speaker when the speaker is explicitly literal. Our findings reveal that people overwhelmingly do not do so and instead behave as literal listeners, and that nudging participants to consider alternative messages does not improve performance. This suggests that while people readily consider the speaker's intent, they do not tend to engage in ad-hoc reasoning about probabilities of alternative messages in the absence of a rational speaker.