The central goal of my research is to understand how evolution has shaped the social mind. To this end I apply theoretical tools from evolutionary biology to develop hypotheses regarding function, then generate information-processing models that specify how the functional mechanism operates, and then empirically test the validity of these models. I study a range of phenomena including kinship, altruism, sexuality, disgust, morality, and, more recently, gratitude. Below I provide a brief summary of three strands of my ongoing work.