抄録
Previous studies have shown an induction phenomenon in the rat, i.e. a considerable decrement in behavior variability and facilitation of a running response, when reinforcement was presented after or between non-reinforcement trials in the semi-circular maze. The purpose of the present experiment was to determine whether or not a similar effect was found when the reinforced test trials were given after simple maze exploration instead of usual procedure of non-reinforcement.
Thirty rats deprived from foods were devided into three groups (Group 2-days, Group 7-days, and Group Pseudo-extinction). After initial exploration and pretraining, Ss were given 20 exploratory trials per day in the semi-circular maze. This procedure was repeated for 2 days in Group 2-days, and for 7 days in both Group 7-days and Group Pseudo-extinction. On the following day, Ss in both Group 2-days and Group 7-days were given 20 reinforced test trials, and Ss in Group Pseudo-extinction received these test trials after 60 non-reinforced (exploratory) trials.
The results obtained during the test trials were as follows:
1) When the data of Group 2-days and Group 7-days were compared with those of the previous study in which the same number of trials as Group 2-days and Group 7-days were given with reinforcement before the test session respectively, significant decrement of behavior variability was found in both groups. However, there was no significant difference in the running time between each of the compared groups.
2) When compared with the previous study, almost the same amount of induction-like phenomenon was found in Group Pseudo-extinction. These pseudo-induction phenomenon increased with the number of exploration trials. This tendency would be similar to the relationship found between the induction and the number of non-reinforcement in the previous studies.
From the above results, it is suggested that induction seems to be closely related to the exploratory experience or recognition of non-reward but not to the internal factors, such as drives or frustration.
