A developmental and cross-cultural study of the influences of rule structure and problem composition on the learning of conceptual classifications

Five experiments were conducted permitting direct comparisons in the way Ss of different ages and cultures solved conceptual problems. One group of problems (Traditional) could be solved using a reference rule of conjunction or disjunction. Another group of problems (Intradimensional) could be solved either by one of the reference rules, or by a structurally simpler rule. Analysis of American performance confirmed that older Ss not only solved using the simpler rule more often than younger Ss, but when they did so they solved faster. For both American age groups, solution using the simpler rule led to no difference in performance between conjunctive and disjunctive Intradimensional problems. Conjunction proved easier than disjunction only for the Traditional problems. Unlike Americans, the Kpelle of Liberia did not solve using the simpler rule, and found conjunction easier than disjunction for both Traditional and Intradimensional problems. When a memory aid was provided the Kpelle showed a pattern of performance exactly like Americans.