抄録
A circle, accompanied by another concentric circle outside, appears phenomenally larger than that of the same size with no concentric one. When the outer concentric circle (‘conditioning circle’) is enlarged gradually, we have such experience that the inner circle (‘conditioned circle’) diminishes in size, until it appears to be smaller than a circle of the same size without the concentric one. (Naturally, there is a region where both circles, the single and the ‘conditioned’ one seem equal.) Everyone experiences such a phenomenon, but everyone does not experience it equally. There are individual differences among observers. In enlarging the outside circle, or the ‘conditioning circle’ according to the writer , the range of region where the inside circle, or the ‘conditioned circle’, appears larger or smaller than the single circle varies among observers. They coincide in the maximum point in the region in judging the ‘conditioned circle’ larger, while they fail to agree in their judgement of the circle becoming smaller.
We can also experience the phenomenon using other kinds of figures (triangle, square, hexagon etc.).
The phenomenon which occurs in the region of the judgement‘larger’ is remarkable, when the following conditions are fulfilled:
The ‘conditioned figure’ lies inside the ‘conditioning figure’ (This is the most important conditions).
The above-mentioned figures are concentric, of similar figures in similar positions and are drawn on a plane of the homogeneous brightness.
They are thus perceived at once in close connection each other, but they are not figurally connected.
