This theoretical paper discusses some conceptual and methodological obstacles that one encounters when analyzing the contextual determination of thinking in psychology. First, we comment upon the various representations of the "cognitive" individual that have been formed over the years--from the epistemic subject to the psychological subject, and finally, to the psychosocial actor. Second, we recall the main criticisms of "methodological solipsism" found in cognitive psychology research, and we discuss heuristic methods for analyzing the contextual determination of thinking in psychological studies. Finally, we propose an analysis of some data using the approach based on interlocutory logic as a way to formalize reasoning moves and their transformations in the unfolding interaction. (Contains 1 table and 1 figure.)