The construction of cognitive tests is largely based on a Thurstonian model of the structure of the intellect, with test content described in terms of loadings on broad constructs called factors. Knowledge of factorial content of a test does not necessarily correspond to knowledge of mental activities elicited by test performance. Modern cognitive theory, on the other hand, attempts to describe basic human information processing, but may not adequately accommodate individual differences. The integration of psychometrics with information processing theory would benefit both disciplines. In educational assessment, evaluations done at a number of points in time during acquisition of competence could lead to better understanding of cognitive processes (as opposed to cognitive products alone). This paper reviews theory relevant to these related disciplines and proposes six assessment methodologies: (1) assessment of metacognition; (2) faceted tests; (3) measures of structures of knowledge; (4) error analysis; (5) learning potential and transfer; and (6) assessment of information processing styles. Implications are considered for adaptive education, for basic research (especially cross-cultural) on strategies of problem solving and task execution, and for assessment in multicultural settings such as South Africa. (Author/LPG)