With Jorie Koster-Hale, Rebecca Saxe, Jennie Pyers, Rachel Benedict, Rachel Magid and Jenny Lu
Some deaf people cannot effortlessly acquire a spoken language in the way that hearing people can. The majority of these deaf children are born to hearing parents who do not yet know sign language. As a result, these children are often delayed in learning their native language.
Children who learn language late also hit social cognitive milestones late. One of the most prominent examples is that these children have difficulty learning that other people have thoughts and beliefs that are different from their own (this is called Theory of Mind). In this project we want to know how delayed language acquisition affects the neural underpinnings of Theory of Mind.
Typically developing hearing adults have a brain region that specializes in Theory of Mind. In childhood, this brain region is involved processing all kinds of social information, but as children grow it becomes specialized just for Theory of Mind. Our preliminary results show that the same brain region specializes in Theory of Mind in deaf adults who learned sign language from birth. However, in deaf adults who had delayed language acquisition this brain region is not specialized for Theory of Mind; like hearing children it is involved in processing all kinds of social information. This work shows that there are consequences of delayed language acquisition on the neural underpinnings of social cognition, and that these effects last into adulthood.