ON THE SOLVING OF CODE ITEMS DEMANDING THE USE OF INDIRECT PROCEDURES
ALISON C. CAMPBELL · British Journal of Psychology · 1965
Subjects in experiments using categorization and matching problems have been found to encounter difficulty with procedures that are indirect, and involve transformations of data. The present study finds this difficulty to extend to compound code items, many subjects not being able to cope with the type of indirect procedure that solution of these items was made to entail. It is suggested that the difficulty stems from a need to work with equivalence classes that are negatively defined and purely verbal, or the fact that the data transformations called for involve a change of logical subject.