 An important step in any explanation is delineating the target phenomena itself. In cognitive science, this step often takes the form of characterizing a capacity via task analysis, which amounts to identifying and distinguishing the tasks or functions that are performed in exercising the relevant capacity. For example, some tasks currently thought to be central to the functioning of a norm system include those mentioned above: acquisition, compliance, and enforcement. Another step is concerned with modeling the psychological mechanisms responsible for carrying out those tasks: the typical algorithms and patterns of information processing that perform those functions. The final step in completing a full account of a capacity would be an explanation of how those mechanisms and algorithms are implemented and thus realized in the person’s physical, chemical, and biological structures (see Marr 1982 for the classical discussion of these different levels of explanation).