Understanding Other Minds

Human beings spend vast amounts of time thinking about what other people believe, want, hope, and fear. Understanding other minds is part of our social nature and forms the basis of the social fabric of our communities and our world. For the past 35 years, a large research field has explored the inner workings of mental state reasoning, broadly known as Theory of Mind (Baron-Cohen et al., 1985). At the core of this field lies the question of how Theory of Mind develops – namely, how children come to understand that other people have beliefs, desires, intentions, and other mental states that can be used to explain or predict behavior. Many studies have focused specifically on how children develop the understanding that access to information and the resulting beliefs in other people’s minds may be different from their own, and that sometimes other people can hold beliefs that are false (e.g., Scott & Baillargeon, 2017; Wellman, 2014). From the perspective of language acquisition, the ability to entertain thoughts about other minds can help explain how children acquire language so rapidly and without overt instruction. Most obviously, perhaps, Theory of Mind mechanisms can contribute to the discovery of semantic meaning; for instance, children can infer the meaning of a novel word by consulting the speaker’s eye gaze or mental state (Baldwin, 1991; Bloom, 2000). Furthermore, understanding other minds allows learners to bridge the gap between what words and sentences mean and what a speaker intends to communicate by uttering them in a specific context – for instance, whether the speaker is being literal or ironic (Grice, 1975; Sperber & Wilson, 1986). Thus, from the perspective of the young learner, the ability to think about other minds can be used both to constrain hypotheses about what a novel word means and to contextually enrich the meaning of known words and structures. However, the nature of mindreading abilities, their availability and growth in both humans and other animals, and their specific contribution to language learning are all still a matter of debate. With these issues in mind, the present author and the leadership of the Society for Language Development organized a symposium on the topic of “Understanding other minds” on November 12, 2018, at Boston University. The invited speakers were Gyorgi Gergely, Alexandra Rosati, and Jill deVilliers. The goal of the symposium was to highlight classic and more recent findings and theorizing in this rapidly changing field, and to promote discussion of where the field should go next. The three speakers were later invited to prepare articles for a special section of Language Learning and Development dedicated to the same topic. One of them, Gyorgi Gergely, was not able to contribute a paper within the timeframe of the volume. The present special section represents two important perspectives on how we understand others, how this understanding relates to language, and how thoughts about others might originate in our primate relatives. In her article, Jill deVilliers addresses the question of how mental state language and the understanding of propositional attitudes relate to each other. The paper raises the possibility that properties of natural language might promote – and not simply reflect – mindreading abilities. Specifically, deVilliers speculates that some propositional attitude meanings come about through the syntax of natural language and considers several possible mechanisms that might produce this result. One possibility is that language may provide representational and/or computational resources that facilitate