Limits on theory of mind use in adults

By 6 years, children have a sophisticated adult-like theory of mind that enables them not only to understand the actions of social agents in terms of underlying mental states, but also to distinguish between their own mental states and those of others. Despite this, we argue that even adults do not reliably use this sophisticated ability for the very purpose for which it is designed, to interpret the actions of others. In Experiment 1, a person who played the role of "director" in a communication game instructed a participant to move certain objects around in a grid. Before receiving instructions, participants hid an object in a bag, such that they but not the director would know its identity. Occasionally, the descriptions that the director used to refer to a mutually-visible object more closely matched the identity of the object hidden in the bag. Although they clearly knew that the director did not know the identity of the hidden object, they often took it as the referent of the director's description, sometimes even attempting to comply with the instruction by actually moving the bag itself. In Experiment 2 this occurred even when the participants believed that the director had a false belief about the identity of the hidden object, i.e. that she thought that a different object was in the bag. These results show a stark dissociation between an ability to reflectively distinguish one's own beliefs from others', and the routine deployment of this ability in interpreting the actions of others. We propose that this dissociation indicates that important elements of the adult's theory of mind are not fully incorporated into the human comprehension system.