This paper mainly dealt with the following problems by using a number-code substitution task: What kind of relation is there between reactive inhibition (IR) and reinforcement? Does reactive inhibition develop, whether reinforcement is given to subjects or not? Eight groups were so constructed that three variables (the intertrial rest, the rest inserted after twenty trials, and the verbal reinforcement) would be operated. The performance in 20 prerest trials and the reminiscence were compared between each group. The subjects in each group had 30sec practice in each trial. The following results were obtained: (1) The performance of the distributed-practice groups was superior to that of the massed-practice groups. (2) The group who had the intertrial rests of 1min was superior in the prerest performance to the group who had 15sec for each intertrial rest. (3) The performance of the 15-second rest group who was rewarded during each interval was not superior to that of the group who had 15sec for each intertrial rest with no reward. (4) The massed-practice group showed the statistically significant reminiscence. (5) The 15-second rest group showed the statistically significant reminiscence after the 10-min rest. (6) Whether reinforcement was given to the subjects or not, the reactive inhibition developed. This suggests that the reactive inhibition process is very similar to that of fatigue, though it is not clear whether this inhibition process is peripheral or central in the nervous system.
The experiments were designed to investigate the optimum illusory effects of the various stimulus factors in Lipps figure (Fig. 1). Variables operated were as follows: (1) d′; distance between refracting lines X and Y (Fig. 6), (2) α, β; angle of refraction in X and Y (Fig. 2). (3) x′, y′; length of accessory lines attached to principal lines x and y, respectively (Fig. 2). (4) Spatial conditions of Lipps figure placed in vertical, horizontal or oblique directions, H, V, h, v, h′, f. Results obtained were as follows: A. The direction of the principal line x in the refracting line X of Lipps figure was seen relatively gently and the direction of y in Y steeply. But, in the absolute deflection, the direction of x in X alone was peen steeply as y in Y alone. After all, the positive illusory effects of Lipps figure were mainly due to the interaction between X and Y in XYX-or YXY-type arrangement (Exper. IX), B. Factors related of form: (1) The effect of the factor of the accessory lines presented the monotonic increasing curve in variation of x′ and the mountain-shaped curve in variation of y′. The maximum points appeared in x′/x=1 and y′/y or y′/d′=1/2 (variations; x′=0-7cm and y′=0-5cm. Exper. III and IV). (2) The effects of the factors of the refracting angles presented the mountain-shaped curves in variations of both α and β. The maximum points appeared in α=-20°--30° and β=15°-20° (variations; α=0°--75° and β=0°-90°. Exper. V, VI and VII). C. Factors related to spatial conditions: (3) The illusory effect of the factor of the distance between X and Y presented the monotonic increasing curve in variation of d′ (variations; d′=0-7cm. Exper. I and II). (4) The minimum illusory effect of the factor of the spatial rotation (anisotropy) of Lipps figure as a whole appered in H- or V-position, where the directions of principal lines coincided with the ordinate or the abscissa, and the maximum in h′- or f-position, where neither the direction of principal lines nor that of the other side-lines l and l′ forming a parallelogram together with them coincided with the ordinate or the abscissa (Exper. VIII). In conclusion, the specific effect in Lipps illusion of direction is caused by the interaction between different kinds of refracting lines X and Y the interaction regulated by the distance d′ and the interior angle φ of parallelogram (Fig. 6). However, the effects of other factors such as the length of accessory lines, the angle of refraction and the anisotropy can never be neglected.