Sources of individual variability in a pragmatic reference game: Effects of reasoning and Theory of Mind

While in theory people are expected to adhere to rational communicative principles, a growing body of work shows that people vary widely in their tendency to draw pragmatic inferences. It has been suggested that these differences may, in part, stem from depth of reasoning: Previous work has shown that individual participants’ response patterns in a pragmatic reference game are predicted by threeprobabilistic pragmatic models of different reasoning depth. However, those models are agnostic to the cognitive traits which underlie those differences. In this study, we systematically investigate sources of individual variation in a pragmatic reference game, where participants are required to draw ad-hoc implicatures of various complexity. We relate the observed variability in reference game performance to cognitive traits, specifically reasoning ability, working memory and Theory of Mind, as well as to the strategies reported by participants. We find a positive effect of reasoning and Theory of Mind on pragmatic inference, with the effect of reasoning being more pronounced for simple implicatures than for complex ones. We do not find evidence for an effect of working memory.