Stimulus selection and memory strategies in concept problems.

Ss were allowed to use zero, one, two, four, or eight markers to signify the category (positive or negative) of previously selected stimuli in an attribute identification problem. The more markers available and used, the fewer trials were required for problem solution. Ss were indifferent to marker valence (positive or negative) in disjunctive problems but showed a definite preference for (the more informative) negative markers in conditionals. Performance of Ss was correlated with their tendency to move markers from lesser to more informative instances. An interpretation of results based on individual differences in information processing activities is suggested.