The sensitization and differentiation of dimensions during category learning

The reported experiments explored 2 mechanisms by which object descriptions are flexibly adapted to support concept learning: selective attention and dimension differentiation. Arbitrary dimensions were created by blending ph otographs of faces in different proportions. Consistent with learned select ive attention, positive transfer was found when initial and final categoriz ations shared either relevant or irrelevant dimensions. Unexpectedly good t ransfer was observed when both irrelevant dimensions became relevant and re levant dimensions became irrelevant, and was explained in terms of particip ants learning to isolate one dimension from another. This account was furth er supported by experiments indicating that conditions expected to produce positive transfer via dimension differentiation produced better transfer th an conditions expected to produce positive transfer via selective attention , but only when stimuli were composed of highly integral and spatially over lapping dimensions.