The present contribution is centered on the research of cognitive processes and decision making performed in the Risk Analysis and Decision Research Unit at Stockholm University. Methodological aspects of the study of judgment and decision making as cognitive processes are presented in the paper. The process perspective includes a presentation of Differentiation and Consolidation Theory of human decision making which differs from most contemporary decision theories. Empirical results collected over the years and covering problem solving, judgment and decision processes can also be found in the article. The last section presents some issues which are important for future research on human decision processes.