Social interactions are remarkably dynamic, requiring individuals to understand not only how their behavior may affect others but also how others may respond in return. In humans, social interactions are also often dominated by processes such as language and theory of mind which allow us to communicate complex thoughts and beliefs. Understanding the basic cellular processes that underlie social behavior or by which individuals communicate, however, has remained a challenge. Here, I describe naturalistic approaches developed in animals and humans that aim of investigating these questions. First, by developing an ethologically based group task in three-interacting rhesus macaques, I describe representations of other’s behavior by neurons in the prefrontal cortex, reflecting the other’s identities, their interactions, actions, and outcomes. I also show how these cells collectively represent the interaction between specific group members and how they enable mutually beneficial social behavior. Second, by recording from neurons in the human prefrontal cortex during language-based tasks, I describe neurons that reliably encode information about others’ beliefs across richly varying scenarios and that distinguish self- from other-belief-related representations. By further following their encoding dynamics, I also describe how these cells represent the contents of the others’ beliefs and predict whether they are true or false. Finally, I describe how these cell ensembles track linguistic information during natural speech processing and how language can be used to ask specific questions about the single-cellular constructs that underlie social reasoning. Together, these studies reveal cellular mechanisms for interactive social behavior in animals and humans and highlight the prospective use of naturalistic approaches in social neuroscience.


Dr Williams is associate professor in neurosurgery at Harvard Medical School, Massachusetts General Hospital and Faculty at Harvard Medical School Program in Neuroscience and at the Harvard-MIT program in Health Science and Technology. His interests focus on animal and human neurophysiology on topics ranging from interactive social behaviour in mice and primates to decision making and language in humans. He has authored publications on the topic in Nature, Science, Cell and Nature Neuroscience among others. He also performs surgical procedures that focus on functional and reconstructive neurosurgery and teaches on topics in epilepsy, spine and peripheral nerve surgery.