The effect of subadditive pretraining on blocking: limits on generalization.

Recent evidence indicates that prior learning about a set of cues may determine how new cues are processed. If subjects are taught that two reliable predictors of an outcome do not summate when the cues are presented together (i.e., subadditive pretraining), the subjects will tend to show a less profound blocking effect when trained with different cues. Three experiments investigated the conditions necessary for subadditive pretraining to generalize to new cues. Experiment 1 demonstrated that subadditive pretraining is less effective in reducing blocking when it is experienced in a context other than that in which the blocking training is experienced. In Experiment 2, the effectiveness of subadditive pretraining waned with time. Experiment 3 showed that subadditive pretraining is more effective when the temporal characteristics of pretraining cues are similar to those of the cues used in blocking training. These results provide information concerning the conditions under which learning will generalize from one set of cues to another.