IN RECENT YEARS, discovery methods of in struction have gained increasingly widespread sup port (2, 11). As justification, it is pointed out that direct verbal presentation frequently leads to a sort of verbal glibness by the learner without true under standing. Many good teachers, nonetheless, still use some form of exposition. By drawing the at tention of the student to basic principles, they feel that the educational process is made more efficient. Gagne (7: 50) supports this point of view when he asks, Is it [verbalization] bad for problem solv ing because it is expressed in words, or is it bad because it does not have enough words? The literature contains studies which appear to support each of these views. Haselrud and Meyers (9) and Hendrix (10) have found that individually de rived (i. e. discovered) principles were better re tained and led to more transfer than was the case when the Ss were told the principles directly?, The findings of Craig (5), Kittle (13), and Sassenrath (14), on the other hand, indicate that superior learning results when information is given directly. Such apparently contradictory findings can be ex plained, at least partially, in terms of the incon sistent use of the terms direct and indirect (12). Variables other than directness also may be in volved. The results of a study by Corman (4), for example, indicate that kind of information and abil ity both interact with directness. The situation in the classroom is still more com plex. As is becoming increasingly evident to edu cators (11, 1), exposition (E) and discovery (D) re fer to classes of methodology not uniquely de fined methods. In addition, psychologists (8, 2,17) recognize that known learning principles, by them selves, are inadequate to explain many educational situations. Nonetheless, failure to identify many of the basic variables and interrelationships oper ating in the classroom has made it difficult, if not impossible, to study the te aching-learning process in a systematic fashion. Furthermore, any such relationships can be of only passing interest to the teacher unless the variables involved are largely under his control. At the current stage of develop ment, it would seem that more educational research should be exploratory in nature. Too much preci sion, too soon, is at best unrealistic and at worst misleading. The dual purpose of this research was to help determine some variables and interrelationships which complicate experimental comparisons of ex position and discovery modes of instruction and to provide a framework for future more precise ex perimentation. The teaching and learning of prob lem solving in the classroom was of particular con cern.