Used personal expectancy for control and the interactive influences of task explication and task difficulty as predictors of intentional performance and incidental learning. In 2 studies, undergraduate Ss (N = 211) were presented with verbal material to be scanned for typographical errors. Incidental learning was measured by the retention of the content of the material. Results indicate that the internal Ss were superior to the external Ss on both intentional performance and incidental learning. Both the difficulty and explication of the task moderated this relationship, with conditions of high ambiguity and extreme difficulty heightening the differences in performance. There was substantial evidence that degree of task explication differentially affected the cognitive strategies of internal and external Ss. The theoretical significance of such perceptual-cognitive activities and the effect task dimensions have on these activities are discussed for the personality variable of locus of control. (23 ref) (PsycINFO Database Record (c) 2016 APA, all rights reserved)