 To introduce a couple terms of art, accounts of psychological capacities often aspire to provide both a proximate explanation and an ultimate explanation. Where proximate explanations try to answer, “How does it work?”, ultimate explanations try to answer, “How did we come to be like this?” This distinction originates in biology (Mayr 1961; Ariew 2003), but is applicable to behavioral and psychological traits as well (Griffiths 2007). Central to proximate explanations in these latter contexts are the models of the psychological processes that underlie specific capacities. After identifying a relatively complex ability, that ability is explained in terms of the operation and interaction of a set of relatively simpler underlying component mechanisms. Thus, proximate explanations of norms aim to show how human individuals are psychologically capable of the rich array of activity associated with norm-guided behavior by identifying the component parts of the norm system and describing how they operate.