Making a decision is often a kind of conflict resolution in which contradictory goals have to be negotiated and reconciled and a solution constructed. This conflict resolution is highly dependent on problem, context, and individual factors, which obscure and often make it hard to find regularities in human decision processes. The present chapter discusses how regularities in human decision making can be found through empirical research despite these confounding factors. To meet this purpose, Differentiation and Consolidation (Diff Con) theory is presented as a framework for process studies of decision making.

Decision making can be studied using either structural or process approaches (Abelson & Levi, 1985; Svenson, 1979). In its pure form, a structural approach relates choices and ratings to input variables (e.g., the maximum amount that can be gained, the variability across alternatives in gains and/or probabilities). Psychological intervening variables are derived from psychological theory and behavioral patterns in decision tasks. However, no attempts are made in structural approaches to assess the psychological process at different stages from problem presentation to final decision.

In process approaches the researcher follows and draws conclusions about the psychological process from problem presentation to decision by collecting process tracing measures, such as information search, think-aloud protocols, and other measures, at a minimum of two different moments of time in the decision process. Hypotheses and theories based on process data can later be tested in other process or structural studies.