CANCELED - Colloquium: Michael Platt, University of Pennsylvania

Title: The Neurobiology of Strategic Social Interactions

Abstract: Despite its importance, understanding of the fundamental neural mechanisms mediating strategic social interaction remains incomplete, due to the difficulty of modeling these behaviors in animals. In this talk, I will discuss recent work probing the neurobiology of complex strategic social interactions in monkeys and humans. Both monkeys and humans played two different games—one based on the classic economic game “chicken” and a second based on penalty kicks in soccer—while behavior, gaze, and pupil size were monitored. We focused neurobiological analyses on the middle superior temporal sulcus (mSTS), the hypothetical primate homolog of human temporo-parietal junction (TPJ), and anterior cingulate gyrus (ACCg), which have been implicated in theory-of-mind and empathy, respectively. Despite the multidimensional nature of both games, humans and monkeys played in a remarkably similar fashion, and their patterns of gaze and pupillary responses—a measure of arousal and attention—were virtually indistinguishable. These data suggest similar underlying mechanisms mediate strategic social interactions in both species. As predicted, fMRI and EEG recordings in humans revealed TPJ modulation during strategic interactions. In monkeys, mSTS neurons signaled information about social context, goals and intentions, reward outcomes for self and other, strategy, and whether rewards were obtained cooperatively. ACCg neurons carried less information about strategic variables, especially cooperative reward. Inactivating mSTS reduced responsiveness to opponent’s behavior, degraded behavioral unpredictability, and impaired strategy selection. Together, these findings indicate mSTS evaluates strategies to fit the current behavioral context, consistent with the function of human TPJ in strategic social interaction.