Complex problem solving -: Via regia for theoretical psychology?

Under the heading "Complex Problem Solving" we describe a research programme that primarily aims at the theoretical integration of cognitive, emotional, and motivational processes. In the introductory section, we describe some historical and methodological foundations of our approach. The paper continues with the discussion of three current research topics, namely the analysis of the function of self reflection in problem solving, the investigation into the cultural embeddedness of thinking, and - as an example for an applied project - the study of construction processes in machine building. Finally, we present a sketch of the PSI-theory, a completely formalized theory for the explanation of different aspects of human behaviour in complex situations.