This study demonstrates a process-oriented approach to the analysis of decision making through the example of the interactive route choice problem. The core of the work consists in the design of the methodological framework, combining the psychological research method of thinking aloud for acquisition of data concerning cognitive processes generated in the course of decision making and the method of semantic content analysis for their processing and for drawing inferences. Results show that the process-oriented analysis of decision making has the potential to disclose facts hidden beyond the observed behavior. The analysis of process data obtained during laboratory experiments showed that the set of strategies applied by subjects is much more diverse than is assumed in most existing models of route choice. Subjects compared travel times on alternate routes to choose the fastest one, updated actual travel times by exploratory route switching, insisted on habitual choice of one route, anticipated choices of others to get to the minority side, and so forth. These results suggest that the diversity in observed behavior may be to some extent caused by the diversity in individual portfolios of applied choice strategies.