We aim to understand the cognitive, computational and neural basis of social decision making. We use behavioural tasks online and in the lab, where participants can make decisions alone, or together with other participants. We use game-theory and machine learning models to explain the cognitive processes that drive participants’ behaviour, and to draw predictions for other decision-making scenarios. We use neuroimaging to understand the neural mechanisms supporting the participants’ behaviour, as captured by our models. We also try to examine clinical populations to underscore the social-cogni