The functional-cognitive framework for psychological research implies that functional and cognitive researchers operate at two separate but mutually supportive levels of explanation. From a functionalcognitive perspective, all applied psychologists are ultimately directed at the functional level but they can differ in the way they conduct functional research and the degree to which they seek guidance from cognitive models. We propose a taxonomy that encompasses four different types of applied psychology and evaluate the merits of each type. We also argue that applied psychology can be fortified by strengthening its functional core, thus evolving into a more integrated but still diverse discipline of psychological engineering. Finally, we explore the implications of these ideas for applied memory research.