Ponzo錯視における2種のみえの大きさ変化

山上 暁

doi:10.4992/jjpsy.49.273

TWO KINDS OF APPARENT SIZE DISTORTION IN THE PONZO ILLUSION

AKIRA YAMAGAMI

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JOURNAL FREE ACCESS

1978 Volume 49 Issue 5 Pages 273-279

DOI https://doi.org/10.4992/jjpsy.49.273

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Published: January 20, 1979 Received: June 28, 1978 Available on J-STAGE: July 16, 2010 Accepted: - Advance online publication: - Revised: -
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Date of correction: July 16, 2010 Reason for correction: - Correction: ABSTRACT Details: Wrong : The effects of the converging lines (CL) on the apparent size distortion of the parallel lines (PL) in the Ponzo illusion were examined.
(1) In Exp. I (seven subjects), the apparent size of the single line was measured with the comparison line outside CL. The apparent size varied as a function of the location in CL (F_{0 (9, 60)}=7.45, p<.01); the magnitudes of overestimation decreased monotonically as the line was located further from the apex (Fig. 2).
(2) In Exp. II (same seven subjects), the predicted illusion based on the single line distortion was compared with the measured Ponzo illusion. Obtained illusion became larger as the separation (d) of PL increased (F_{0 (8, 54)}=8.27, p<.01). When the separation was small, the predicted and the obtained magnitudes were almost the same. But as the separation increased, their discrepancy also increased (Fig. 3). This result suggested that the additive effect was operating in the comparison process of the two lines. Therefore, the effect of CL in this comparison process was examined.
(3) In Exp. III, some kind of disturbance in the operations of CL were introduced.
(a) Exp. III-1 (six subjects): When the physical continuity and the oblique conponents of CL were eliminated, the magnitudes of the illusion decreased slightly but this trend was not statistically significant (F_{0 (4, 25)}<1, Fig. 4 A, B, C, D, & P).
(b) Exp. III-2 (six subjects): When only the oblique components were eliminated, the illusion showed some trend of decrease but this trend was not statistically significant (F_{0 (4, 20)}=2.57, p>.05, Fig. 4 E, F, G, H, & P). These results suggested that the physical characteristics of CL had some additive effect on the illusion, but rather the whole stimulus arrangement was thought to be more important from the result of the figure in Fig. 4A.
(4) In Exp. IV (11 subjects), the effect on illusion of contour figures and PL separation was examined. Stimulus figures were shown in Fig. 5. In the S figure series, the separation of each pair of short vertical lines was constant. In all cases of contour variants, the magnitudes of the illusion became larger as the separation of PL increased (F_{0 (2, 150)}=70.36, p<.01). The effect of contour variation (F_{0 (4, 150)}=28.05, p<.01) and the interaction of contour by separation (F_{0 (8, 150)}=3.36, p<.01) were significant.
Based upon all of these results, it was proposed that two kinds of apparent size distortion should be distinguished in the Ponzo illusion.
(a) The apparent size distortion of an individual object in CL.
(b) The apparent size distortion in the comparison process of two objects in CL. The result of Exp. II suggested that these two kinds of apparent size distortion were additive in the Ponzo illusion. To examine this additivity, the measurement of the individual line by the comparison line outside CL is necessary at the same time with the measurement of the illusion.
Right : It was proposed that there are two kinds of apparent size distortion to be distinguished in the Ponzo illusion. The apparent size of the single line in the converging lines (CL) became larger as it was located nearer to the apex. However, this distortion could not predict the obtained illusion sufficiently. Hence there should be assumed another kind of size distortion in the perception of the size relation as a result of comparison of two parallel lines (PL). In this comparison process, breaking of the continuity of CL and elimination of the oblique components from CL had a slight decreasing effect on the illusion. Moreover, it was found in the various contour figures that the greater the separation of PL was, the larger the illusion was.

Abstract

It was proposed that there are two kinds of apparent size distortion to be distinguished in the Ponzo illusion. The apparent size of the single line in the converging lines (CL) became larger as it was located nearer to the apex. However, this distortion could not predict the obtained illusion sufficiently. Hence there should be assumed another kind of size distortion in the perception of the size relation as a result of comparison of two parallel lines (PL). In this comparison process, breaking of the continuity of CL and elimination of the oblique components from CL had a slight decreasing effect on the illusion. Moreover, it was found in the various contour figures that the greater the separation of PL was, the larger the illusion was.

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