This paper outlines the current state of knowledge about how intellectual competence is acquired. Implications resulting from recent changes in the psychology of learning and development are beginning to revitalize the science of learning and instruction. Four broad topics illustrate the links between instructional experiments, fundamental research on learning and thinking, and potential applications to the science of instruction: (1) understanding natural language; (2) learning to read; (3) developing mathematical competence; and (4) problem solving, intelligence, and learning abilities. Major themes emerging from research in language processing indicate that prior knowledge is essential in constructing meaning for a new text and that the construction of meaning centrally involves inference. Two main themes in reading research are emphasized: (1) the active interplay between expectations and the visual stimuli of printed words; and (2) the central role of automatic processes of word recognition. Special problems arise when analyzing mathematics as a domain of cognition and learning, including organizing schemata, recognizing persistent and systematic errors, and linking symbols and their referents. Recent work in problem solving is focused on performance in information-rich domains. There has been considerable effort in recent years to reanalyze the constructs of intelligence and aptitudes in terms of cognitive processes and constructs, including metacognitive skills. Directions for further research are suggested. (LMO)