Maier and Ellen's rats were required to learn to respond to a particular card irrespective of its position (side) after position habits were well developed. The proportion of times that the previously rewarded response was rewarded and punished, was Varied : Group A, 80 : 20 ; Group B, 50 : 50 ; and Group C, 20 : 80. Main results were : (a) in terms of the number of rats giving up the old response and the number learning the new, Group A and C were similarly superior to Group B, (b) the number of trials required by the learners to abandon the old response was the largest in Group A, and Groups B and C followed, and (c) the learners in Group B need the least number of trials to criterion and the other groups were equally inferior in discrimination. All the points except the second, according to the authors, contradicted reinforcement theory, and a perceptual factor of consistency of effect was basic for explaining the results. Similar findings were obtained by Saji et al. and Akamatsu et al. Experiment I was conducted to repeat the Maier-Ellen design using children in a slightly different situation in that two boxes with different colors were' used with a candy as reward. The reward-punishment ratios in color discrimination were the same as Maier et al. The results showed the homogeneity of the three groups in position habits (Tables 1 through 4). Only one S in each of Groups B and C failed to learn discrimination in 90 trials although they abandoned position habits early in trials. This finding may be due to the relative easiness of the discrimination compared with Maier et al.'s. The median number of trials to criterion was the least for Group B and no slgnificant difference appeared between the other two (Tables 5 & 6), while Group A showed the largest number of trials to give up the old response, and Groups B and C followed in this order (Table 7). The two points agreed with Maier et al. New measures were observed in fhe present study. In terms of the percentage of response alternations, Group B was the highest and Groups A and C were similarly low (Table 8). It was indicLted that although Group C was earliest in giving up the old response, they were yet as slow as Group A in abandoning‘position habit’Per se, i. e. whether the persisted response was previously rewarded or not. In terms of the percentage of wrong responses, Group A and C were equally low relative to Group A. In this point, Muenzinger's finding (6) that discrimination was facilitated by punishment, was suggestive. Contrary to Maier's contention, the results may be explained in terms of reinforcement theory in that Group B was most favored in discrimiaated because only in this group the particular (red) box was rewarded irrespective of position (i. e. 50 : 50), while in the other two groups, the same box was reinforced not only with respect to color but also (partially) to position (80 : 20 or 20 : 80). This explanation was confirmed in Experiment II where no previous position learning was included (Table 10). The same results may also be interpreted in terms of‘set’in that Group A and C were similarly slow in abandoning their set of position habit as revealed by the analysis in terms of the percentage of response alternations and thus they were inferior in the new discrimination to Group B. The two interpretations were of course complementary. The weakness of Maier's position seemed to lie in that although it could explain the similarity of Groups A and C but failed to show why they were both inferior to Group B.
The nature of experimental extinction was studied by checking the effect of intertrial intervals in exp. 1, and the rate of reinforcement in exp. 2, upon the rate of spontaneous recovery. In the first experiment, 18 rats were trained on an elevated straight alley, 20 trials per day for 5 days. Then extinction was performed for one group with intertrial interval of 7.5 minutes, and for the other with much shorter interval of a few seconds. The session of spontaneous recovery followed the extinction after 24 hours, in which the intertrial interval was 3.5 minutes for both groups the same as in the training session. The results are shown in Figs. 1 & 2 and Tables 1 & 2. The massed group reached the criterion earlier than the spaced group in extinction while in the session of spontaneous recovery the former showed a relatively high response tendency. These results support the assumption that the extinc-tion is a complex of the transitional inhibition which disappears with time and the permanent one, and the control of intertrial interval seems to regulate the proportion of the amount of those two kinds of inhibition during the session of extinction. In the second experiment three groups, 7 rats for each, were trained on the same alley as the one in the first experiment, 15 trials per day until each individual reached a criterion. The experimental group 1 was reinforced one time and the experimental group 2 two times for every three trials while the control group was reinforced on every trial. Extinction session followed the training. Twenty four hours after the criterion of extinction was reached, the spontaneous recovery was investigate. This time, the intertrial interval was 20 seconds for all sessions. The results are shown in Figs. 3 & 4 and Table 3 & 4. The experimental groups showed greater resistance against extinction than the control groups while the former showed a more spontaneous recovery. This relationship between the rate of reinforcement, resistance to extinction and the spontaneous recovery seems to exist among the experimental groups. Considering the reinforcement as an agent of stimulus complex, the above experimental procedure and results resemble the traditional experiments of retroactive inhibition in memory, in that the rate of reinforcement forms a continuity of generalization between the sessions of training and extinction where the rate is zero. From the above experiments, it is also concluded that the experimental extinction not merely is an arithmetical subtraction of habit acquired in the training but possesses an interaction with the training procedure.
The “dynamic stereotype” of the cortical activity (or the serialization of conditioned reflexes) was shown by pavlov as one of the complicated higher nervous activities. However, there is very little evidence for it. The present investigation was designed to confirm this phenomenon in human subjects and to analyse this function, as well as to procure manerial for future study. Part I of his experiment consisted of the serialization of three positive conditioned reflexes (tone, light, tactile), part II consisted of two positive and one negative onditioned reflexes (metronome, ton (-), tactile), and part III of three positive and one negative conditioned reflexes (metronome, tone (-), tactile, light). After the serialization of CRs was sufficiently established in nine subjects for she CSs which were repeated at equal intervals (part I, 5.5 min. ; part II, III, 4.5 min. intervals) in the same order of succession (the above mentioned orders of CSs), the following results were obtained in four experiments. 1. When only the first CS in the series (part I, tone ; part II, III, metronome) was used, the effect of this single CS on the series was the same as when the entire series of CSs were given. 2. As a substitute for the CSs, the same stimulus (part I, tone ; part II, III, metronome) was applied successively at the same intervals (Part I, 5.5 mil : part. II, III, 4.5 min.). It was found that the conditioned effect of this stimulus changed according to the stimulus it replaced ; that is, in each case, this stimulus produced a reaction not proper to itself but to the stimulus which it replaced. 3. When the order of stimulus presentation in the series was changed part I, [tone, light, tactile]→[tactile, tone, light]; part II, [metronome, tone, tactile]→[tone, tactile, metronome]; part III, [metronome, tone, tactile, light]→[tactile, metronome, light, tone], the disturbance of the series effect in the CR was found. Four types of these disturbances were observed. 4. When intervals of the stimulus bresentation in the series were changed 4.5 min. to 2.25 min. intervals, [4.5, 4.5, 4.5 min.]→[2.5, 2, 9 min.], it disturbed the series effect in the CR also. Besides, the real stimuli effects were found only in cases when these stimuli were applied at equal at intervals. The results confirmed the serialization of CRs in human subjects. The mechanism of the serialization of CRs in the present study indicated that the temporal CR was established by UCS given at regular time intervals, and UCSs being connected with external stimuli (CSs), maked a compound CS. In this way the serialization of CSs were established. These four types of disturbances of the serialization of conditioned reflexes seemed to correlated with Pavlov's ‘type of nervous system’. Analysis of disturbance-types would help towards the study of particular types of CR.
The purpose of the present investigation was to examine the effect of an extra line presented at various spatial loci upon the successive comparison of the lengths of two lines. Besides, the variation of this effect due to the changes of the time intervals between three lines was studied. Three lines were the black ones on a white background in horizontal position. The presentation of these lines were designed as follows. Three lines were presented in succession for the same brief duration, but the time intervals between lines were varied within a short period. A standard line (N) of 30 mm in length preceded the comparison line (V) and they were presented at an identical location. But the extra line (e) was presented at 0, 0.5, 1, 2, 3, 5 or 7 cm distant from the compared lines and e preceded N and V, followed them, or was interpolated between them. The effect of the extra line was measured by comparing PSE obtained by the method of complete series with that of the control experiment where the extra line was not presented. As the-experimental results obtained by the presentations of three lines at an identical location were similar to ones reported in the previous papers, they were not mentioned here. The chief Results were as follows : I. Proactive effect of e in the sequence of e-N-V (1) When e was 60 mm in length and the time intervals of both e-N and N-V were short, V was underestimated. The amount of this effect diminished as the spatial distance between e and N (V) was enlarged. But when the time intervals were more lengthened, V was overestimated. (2) When e was 15 mm, V was overestimated at near position to e, while it was under-estimated at distant position from e. II. Retroactive effect of e in the sequence of N-V-e (1) When the time intervals of both N-V and V-e were short, V was overestimated under both conditions of 60 mm and 15 mm lengths of e. (2) When the time intervals were relatively long, V was underestimated regardless of the length of e. III. Proactive-retroactive effects of e in the sequence of N-e-V (1) When e was 60 mm and the time intervals of either N-e or e-V were longer than that of the other, V was overestimated at near position to e. (2) When e was 15mm and the time intervals were short, V was overestimated at near position to e, but it was underestimated at distant position from e. The above results were ascribed to an assimilation-contrast phenomenon. The present investigation indicates that the assimilation-contrast phenomenon varies not only with the temporal intervals between lines but with spatial intervals between them.
The author indicated in the former studies that many figures of tridimensional appearance contain the forms Y and ↑ in their structures. There are, however, some figures which look tridimensional, though they do not contain thee forms. This stutdy observes and discusses the characteristics of such figures and their relation to the forms Y and ↑. Parallelogram _??_, cross-shape + and L-shape _??_ are tridimensional figures without Y and ↑, when their lateral lines are aslant. Figures of parallelogram were prepared, which had two side lines standing vertically and two side lines aslant in various angles. The experimenter showed them to the subjects who expressed the degree of the apparent depth with a newly devised apparatus. The subjects saw the figures not on the front parallel plane, but with the tridimensional impression always. The conclusion is as follows : The relation between the angles of parallelogram and its apparent depth may be expressed adequately in a linear equation. L-shape looked tridimensional more easily than parallelogram and cross-shape. There-fore one could conclude that the most imprortant factor for tridimensional appearance is the slanting of the lines or the size of the angles. The author had believed that every angle must have its proper solidity, and, now, the result of the experiment proved the correctness of that idea. Parallelogram contains four angles of similar solidity and irregular quadrilateral has four angles of different solidity. The surface of the former looks plane and that of the latter looks distorted. Next it was ascertained that the apparent depths of the figures _??_ and ↓ are more exactly observed than those of the figures _??_ and _??_. The comparison of the figure of the open book with one of the closed book has also shown the same result. The cause of it may lie in the accumulation of the tridimensional impression in their two or three angles. The solidity of necker cube and other solid figures is emphasized in the same way by the accumulation of their partial solid impressions. The function of the accumulation is more effective in the figures containing the angles of different solidity then those containing the angles of similar solidity. Therefore its character may be of the nature of contrast. After all the tridimensional appearance of plane drawings can be explained on the ground of the two facts that every angle has its own solidity and that the solid impression is intensified by accumulation. Thus, it is not necessary to use the principle of good configuration, so far as the depth perception of two dimensional drawings concerns.