This paper briefly describes four kinds of learning carried out by intelligent agents in a computational environment facilitating joint activities of people and software agents. The types of learning and the applications we draw examples from are: learning by being told and learning by experience, as illustrated through a virtual patient application; learning by reasoning, as illustrated through a clinician's advisor application; and learning by reading, as illustrated by an ontology enhancement application. The agents carrying out these types of learning are modeled using cognitive modeling strategies that show marked parallels with how humans seem to learn.