抄録
Problem: Gestalt psychologists, as known well, emphasize the dynamic process of memory traces. According to the theory any learning which has suffered retroactive inhibition (RI) must more or less undergo some change in the retention process. On the other hand the current functionalists' theories of RI, e.g. competition theory, two-factor theory etc., are indifferent to retention process. There is, however, one exception. Recently Underwood contended that there was ‘spontaneous recovery’ from unlearning of original learning. His two experiments (22, 23), together with the experiment of Maeda (16), show the decrease of RI in retention. Newman's experiment (19) also indicates the same tendency, although it does not take any ordinary paradigm of RI experiments.
On the contrary, we are able to find some suggestions as to the increase of RI in retention in the studies of McGeoch and McKinney (14), wulf (25), Isihara (9), etc.
If RI shows increase in retention, the two-factor theory will have to be revised. On the other hand, if the increase is denied, the trace theory will have to be amended
Our study aims to clarify the nature of the process of RI in retention, a problem unfairly neglected so far.
Experiments and their results: Exp. I. Learning materials were two poems which resemb'e to each other closely. Ss reproduced the original learning material immediately after, or 12min., 24 hours and 7 days after the interpolated learning. RI increased for the first 12min. But the processes of RI for 24 hours and 7 days were not different from the retention of the control group.
Exp. II, III. In these experiments two lists which consisted of 15 four-syllable nouns were learned, and reproduced immediately, 12min., 24 hours or 7 days later. We could not find any change in RI throughout.
Exp. IV. Two sets of six pairs of nonsense syllables in Japanese letters were learned by anticipation method, and relearned immediately, 12min. or 5 hours later. Percentage of RI was found to decrease between 12min., and 5 hours after the interpolated learning.
Thus. RI seems to increase, remain constant or decrease according as the conditions vary. In order to give a consistent explanation to these inconsistent results we assume a new factor “interference” which competes with “spontaneus recovery” from unlearning. The process of RI in retention is supposed to be determined by the relative strengths of these two antagonistic forces.
