Effects of pretraining US density and test ITI upon the acquisition of autoshaping

Four groups of pigeons were tested for the acquisition of autoshaping to a green key CS following 30 days of pretraining involving intermittent, unsignaled US (food) presentations. The groups were arranged in a 2 by 2 factorial design with two levels of pretraining schedule (VT 30 sec vs. VT 90 sec) and two levels of test schedule (VT 30 sec vs. VT 90 sec). The data revealed a main effect of test schedule such that subjects tested under the VT 90-sec schedule acquired the keypeck CR faster than subjects tested under the VT 30-sec schedule. There was no main effect of pretraining schedule and no interaction effect between pretraining and testing schedules. Implications for theories of acquisition and retardation of autoshaping are discussed.