Abstract

Growing evidence indicates that our higher rational capacities depend on social interaction—that only through engaging with others do we acquire the ability to evaluate beliefs as true or false, or to reflect on and evaluate the reasons that support our beliefs. Up to now, however, we have had little understanding of how this works. Here we argue that a uniquely human socio-linguistic phenomenon which we call ‘joint attention to mental content’ plays a key role. JAM is the ability to focus together in conversation on the content of our mental states, such as beliefs and reasons. In such conversations it can be made clear that our attitudes to beliefs or reasons may conflict—that what I think is true, you might think is false, or that what I think is a good reason for believing something, you might think is a bad reason. We argue that through JAM, children discover that mental contents can be evaluated under various attitudes, and that this discovery transforms their mind-reading and reasoning abilities.