Every scientific researcher proceeds rationalistically as well as empiricistically. Each may be classified in terms of a tendency to one or the other pole but not in terms of either-or. The literature of the philosophy of science discusses the wisdom of empiricistic or rationalistic approaches. This paper, however, is empirical rather than philosophical. Consequently, it does not discuss the problem of wisdom, but rather examines 1 the extent to which empiricistic and rationalistic orientations are found in research reports of a single field, that of human behavior in stressful situations, and 2 the personal and social conditions which are associated with each of these orientations. It is concluded that the tendency to increase the proportion of observation terms among researchers in this group to be empiricistic increases when a researcher is working in a field not his own, when he is a younger professional, when his personality tends to be introverted, when he is a non-Catholic and when he is politically conservative. All of these tend to be characteristics associated with the lack, either actual or by desire, of the attitude labeled certitude. A greater proportion of theoretical terms are used as indicators, the rationalistic orientation, in the research reports of individuals working in their own field, when they are older professionals, extroverted, Catholic or politically liberal. These are characteristics associated with enjoying certitude.