大きさの継時比較 II

Abstract

The effect of an interpolated circle on successive comparisons of size of circles were studied from two points of view, that is; (1) illusion of the concentric circle based on the trace of the standard stimulus S1, and (2) figural after-effect to comparative stimulus S2.Method: The stimuli were circles drawn on a white sheet of paper with a black line 1mm wide, and they were presented by the modified Dodge's tachistoscope. The observer judged the size of S2 which has the same size as S1 of a diameter of 30mm. D% or (S-L)/N was measured, in which S means number of “smaller” judgements and L number of “lager” judgements and N total number, The differences in D% between the experimental series and the control series in which the circle was not interpolated were computed.Results: 1) when S1 and S2 were presented on the right and left side respectively with a fixtion point in the central point, (a) we obtained result as expected from figural after-effect of an interpolated S or Si to S2 when Si was presented at the same position as S2. but (b) we couldn't find any definite finding when Si was presented at the same position as S1, (Exp. I, Table 1).2) The latter finding (b) cannot be ascribed to the experimental procedure in which ratio of judging large and small sizes to the isometric S2 to S1 is used as an amount of displacement. Similarly no definite trend was obtained with the method of complete series (Exp. II, Table 2).3) If the summation effect is possible when S1, Si and S2 are presented at the same position, we can explain the effect of Si in terms of figural after-effect of Si to S2, and we obtained affirmative results (Exp. III, Fig. 1, Table 3, 4).4) Using the procedure of simultaneous comparison similar to that used in figural after-effect, we measured directly the amount of displacement of S2. (Exp. IV, Fig. 1, Table 5, 6). The effect of figural after-effect was greater in this case than in the case of successive comparisons. It means the decreases of assimilation in Exp. III from the view of theory of assimilation (Table 7, 8).5) It was examined to what extent we can explain the previous results on time error by figural after-effect.