Learning conceptual rules: III. Processes contributing to rule difficulty.

Eight unique bidimensional conceptual rule forms were compared in a rule learning paradigm. It was predicted that rule difficulty order and error distributions across stimulus class defined by a truth table would be a function of Ss' preexperimental experience predominantly with conjunctive concepts. The hypothesis stated specifically that loci of difficulty with rules derive from: (a) assignment of TT stimuli (those with both relevant attributes) to the negative category; (b) assignment of FF stimuli (those with neither relevant attributes) to the positive category; (c) assignment of TT and FF stimuli to the same category. The main effects of rule and truth table class and the interaction of rule and truth table class were statistically significant. The results confirm all predictions about rule order and error distributions.