This relevance-based account of commitment borrows from studies on epistemic vigilance and focuses on the hearer’s perspective. It suggests that commitment determines the strength of the contextual assumptions derived from utterance interpretation. this contribution distinguishes four kinds of commitment: speaker commitment, communicated commitment, attributed commitment and hearer commitment. The last two kinds of commitment are influenced by three main factors which will be considered in turn: linguistic markers, the hearer’s appraisal of the speaker and the salience of the communicated assumption in his cognitive environment. These claims translate into four experimentally testable predictions. This proposal echoes the current debate concerned with epistemic evaluation of information and aims to account for individuals’ commitment in terms of the relative strength of stored assumptions in their cognitive environment.