This paper reviews some of the research findings relating to the issue of personalism versus situationism in the psychology of personality. The recurrent controversy regarding the relative importance of situations, personal dispositions, and interactions between these is addressed with a focus on the manner in which persons perceive, construe, and subjectively quantify the signals coming to them from other persons in their life-space. The possible idiosyncracies of persons in their construing of other people and their behavior are seen as promising means of understanding person-by-situation interaction in the determination of complex social behavior. (SJL)