The project Thought Sharing in Action: A Naturalistic Approach (TSA) delves into the heart of I–You personal interactions—face-to-face exchanges in which minds seem to meet, yet in which individuals also act in markedly different ways. The project goes beyond traditional linguistic settings among adult humans to shed new light on the proper relationship between thoughts in successful personal interactions, placing central emphasis on empirical data from infant cognition and nonhuman animals, as well as the most recent advances in artificial intelligence. In this way, TSA will redefine thought sharing in I–You interactions, developing a far-reaching naturalistic model for communication and the explanation of action.