ON THE DISCRIMINATION OF AVOIDANCE CONDITIONING IN THE WHITE RAT
1966 Volume 37 Issue 5 Pages 278-286
Details
1966 Volume 37 Issue 5 Pages 278-286
This paper consists of two parts. In part I (Exp. I and II), two factors on the discrimination of avoidance conditioning (AC) were analysed.
(Exp. I) The purpose was to analyse the effect of stimulus similarity. Method Ss: 26 male albino rats. Apparatus: The modified Mowrer-Miller shuttle box. Procedure: After the establishment of AC to CS (2,000cps pure tone), Ss were divided into three groups and given discrimination training. Reinforced stimulus (S+) for each group was 2,000cps tone and each non-reinforced stimulus (S-) for Group I, II and III was, 500cps, 1,000cps, and 1,500cps, respectively. The Ss of each group were given twenty daily trainings for 15 days. Results 1) The discrimination learning curves for three groups are shown in Fig. 1, 2 and 3. A comparison of the number of responses of S+ to that of S- indicated significant differences for Group I and II, but not for Group III. 2) The progresses of discrimination ratio (S+-S-/S+) for three groups are presented in Fig. 4. An analysis of variance on the ratio revealed significant difference among three groups (See Table 2).
(Exp. II) The purpose was to analyse the effect of strength of UCS to S+. Method Ss: 30 male albino rats. Apparatus: The same apparatus as in Exp. I. Procedure: Ss were divided into three groups and conditioned avoidance response to CS (2,000cps tone) using UCS strength of 0.4mA shock for Group W, 0.5mA for Group M and 0.6mA for Group S. After the establishment of AC, discrimination training between 2,000cps (S+) and 1,000cps tone (S-) was given for 15 days. The UCS strength of each group to S+ was the same as in conditioning period. Resuits 1) The progresses of discrimination ratio for three groups are presented in Fig. 5. An analysis of variance on the ratio indicated no significant difference among three groups. (See Table 4). 2) These results of Exp. I and II suggested that the discrimination of AC was affected by the similarity of S+ to S- and not by the UCS strength to S+.
In part II (Exp, III), the procedures of discrimination in AC were considered. Although the fundamental conditions of discrimination learning are to give S+ reinforcement and S- non-reinforcement, the conditions are not satisfied in case of discrimination of AC especially when stimuliare very similar. Therefore, it is inferred that special procedures are necessary to the discrimination of AC.
(Exp. III) The purpose was to compare following two procedures; 1) S+ and S- were both stopped as soon as Ss finished response. 2) While S+ was stopped simultaneously with finish of response, the termination of S- was not syncronized with response, but delayed. In case of the discrimination of AC, the latter procedure was theoretically considered necessary to statisfy the basic conditions for discrimination. Method Ss: 39 male albino rats. Apparatus: The same apparatus as in Exp. 1. Procedure: Group IT and ID made discrimination between 2,000cps (S+) and 1,500cps tone (S-), and Group IIT and IID did between 2,000cps and 1,000cps. The discrimination procedure was the first one for Group IT and IIT, and the second for Group ID and IID. The training was continued for 20 days. Results 1) The curves of discrimination learning are presented in Fig. 6 and 7.2) Table 5 shows the mean discrimination ratio in the last 2 days of training for each group.
