Research related to the training and measurement of cognitive skills (effective behaviors in situations in which events must be organized or structured in some way) represents a point of common ground between the educator and the behavioral scientist. That we so seldom train for generalized cognitive skills is paradoxical, for most authorities tend to assume these skills enable the student to learn a wide variety of instructional content. Research on whether or not generalized skills interact with instructional content to facilitate learning is now under way. Knowledge of how cognitive skills develop is limited, but some findings suggest that research should concentrate on the more advanced stages of formal operations. It may be possible to develop more efficient and precise measures than those of Piaget. If so, they may be useful in evaluating educational programs because (1) measures of fundamental cognitive skills provide highly meaningful descriptive information about learners, (2) knowing the level of cognitive development attained by learners should provide significant information as to interactions between instructional phenomena and learning, and (3) we may find that the development of some cognitive skills is actually facilitated by a given instructional program. (JS)