Speech act matters: Commitment to what's said or what's implicated differs in the case of assertion and promise

Speakers take responsibility for their utterances in communication. Theoretical literature has suggested that speakers are more committed to what they explicitly say than what they implicate, but recent empirical studies have shown mixed results. This study readdresses the issue of speaker commitment attribution (i.e., to what's said vs. to what's implicated) by taking into account the factor of speech act (i.e., assertion and promise). Results showed that while speakers were more committed to what's said than what's implicated in an assertion, they were perceived to be equally committed to the said and implicated contents of a promise. We suggest this should be attributed to the difference in the nature of the implicated propositional content of the two speech acts, which was evidenced by participants' higher degree of certainty of the implicature derived from promise than assertion. The results suggest that commitment to what's said or what's implicated is not a fixed phenomenon and that speech act is an important factor that cannot be neglected in commitment study. In the end, we propose an experimental paradigm that contributes to future empirical study of speaker commitment at the theoretical and psycholinguistic crossroads. • Commitment to what's said or what's implicated is not a fixed phenomenon. • Speakers are more committed to what they say than what they implicate in assertion. • Speakers are equally committed to what they say and what they implicate in promise. • Factors that affect speaker commitment are measurable through experiments.