Interaction between humans and artificial intelligence (AI) is still lacking the degree of engagement and entrainment that characterizes interaction between humans The project WithMe aims at bridging this gap by investigating in detail the processes that happen in the human brain when engaged in an activity together with an other person: pursuing a common goal or  simply enjoying a common activity The brain signals that will be explored are characteristic for attention, emotion, and reward Based on findings with people, WithMe will investigate the characteristics of an audiovisual interaction that makes it feel human, but the project will also explore whether an AI system could benefit from direct access to biomonitoring of the person it is communicating with The new human-AI approach thus derived will open a wealth of new applications in health, revalidation, communication and information sharing, entertainment, etc