The quest for determining the degree of learning difficulty associated with different types of categories has been instrumental in our understanding of human categorization behavior and, more broadly, human generalization. For instance, we now know that the topological nature of the dimensions (e.g., whether these are integral or separable) that…

Much recent research and theorizing in the field of reasoning has been concerned with intuitive sensitivity to logical validity, such as the logic-brightness effect, in which logically valid arguments are judged to have a "brighter" typeface than invalid arguments. We propose and test a novel signal competition account of this…

The investigation of interactions between the abilities of stimulus discrimination and simple learning and two instructional variables (discrimination difficulty and degree of overlearning) with 27 mentally retarded adolescents found an interaction between stimulus discrimination and the number of words presented at one time for learning…

Three studies were conducted to investigate reasons for the difficulties that children under 5 years of age experience with class inclusion tasks. The studies tested the claim that such tasks have a structural complexity that is beyond the children's processing ability. In experiment 1, class inclusion tasks were compared with other classification…