Abstract
The aim of this study was to explore the way in which experienced psychologists approach the problem of integrating theory, and to identify commonly used principles and heuristics that students might employ to support their own integration of theory. Eighteen experienced applied psychologists were interviewed, and data were analysed using a phenomenological approach. It was concluded that integrating theory may be understood as a series of problems to be solved, although much of the decision-making may be implicit rather than explicit. Despite the huge variation between participants, it was possible to clarify the various components of integration, to identify some common principles and heuristics, and to sketch the process by which each psychologist develops an idiosyncratic personal body of psychological knowledge.
