Sidmanian avoidance training in rats was performed with a revised apparatus and some considerablly effective learnings were observed through three experiments. A shock-transmitter mechanism made with ball bearings brought succesively scrambled AC 20 V shocks to a grid conforming the surface of a rotating cage. A same avoidance training schedule was used in the three experiments. This is shock-shock interval was 5s, response-shock interval was 20s, and a shock duration was 0.5s. In Experiment 1, the main variable was the magnitude of rotation to be counted as a response, with two variables of a half and a quarter of one round, respectively. Although under both conditions rats could easily acpuired avoidance responses, the criterion of a quarter rotation was more effective than that of a half. In Experiment 2, the maintenance of learning over night was tested. Rats showed some superior maitenance of avoidance response without any over-night decrement for consecutive 8 days. Rats ran a mean of 504 m/h continuousely, and number of shocks recieved reduced to 0-3 times/h at the last day. In Experiment 3, the continuation of avoidance responses through a long session, using rats which had already learned the avoidance responses. Avoidance responses were continued until the end of the session over 6 hours, and animals ran a mean of 1544m with a mean of 42 shocks during 6 hours.

View full abstract

The present experiments with goldfish were attempted to examine the effects of US and CS intensities on classical conditioning of shuttling response. Every subject was given daily 10 classical conditioning trials, each of which consisted of a 10 sec CS immediately followed by a 0. 4 sec US. In Experiment I, 80 subjects were given either of eight intensities (0, 0. 2, 0. 4, 0. 6, 0. 8, 1. 0, 1. 2, 1. 4V/cm) of US. The results showed that, performance remained at low but substantially higher than zero in the low US intensites (0, 0. 2, 0. 4V/cm), then increased up to 0. 8V/cm, thereafter unchanged (Fig. 1, 2, 3). It was suggested that, with considering high level of general activity, some care should be taken when the CS control group is used in similar experiments. In Experiment II, 50 subjects were given either of five intensities (0, 25, 50, 75, 100V) of CS. The results showed that each asymptotic level of performance referred to a linear function of the CS intensity (Fig. 4, 5, & 6). The results seemed to contradict with the prediction from the Rescorla-Wagner model, which assumes that the CS intensity does determine the rate of conditioning, but not its asymptotic level.

View full abstract