 In this entry we will discuss formal accounts of conversational implicatures that explicitly take into account the interactive reasoning of speaker and hearer (e.g., what speaker and hearer believe about each other, the relevant aspects of the context of utterance etc.) and that aim to reductively explain conversational implicature as the result of goal-oriented, economically optimised language use. For this entry, just as in traditional analyses of implicatures, we will assume that sentences have a pre-existing semantic meaning and will mostly focus on generalised conversational implicatures.