Perceptual Isolation and List Difficulty in Serial Learning

Experiment I, in which learning occurred by the anticipation method, showed that the magnitude of the isolation effect and use of the isolating stimulus as a cue were inversely related to list association value (AV), extending the generality of prior findings. In order to provide a more direct test of item differentiation, response-learning requirements were minimized through the use of a reconstruction procedure in Experiment II; isolation effects in this study showed no dependency upon AV. The apparent contingency on response-learning requirements was discussed; results of similar studies, in which item differentiation had been dealt with more directly as intralist similarity, were also considered.