Abstract:
The so-called subjective-contour effect was examined in touch and compared with vision. The first experiment was designed to establish a criterion of the subjective pattern by modal completion. In experiment 2, free verbal reports were gathered from naive subjects. Verbal reports and rating scores for three characteristics, subjective pattern, depth displacement, and brightness transformation, were gathered from the well-trained subjects in experiment 3. Results were as follows. (1) The effect was strong in vision especially for the pattern. Subjective pattern was reported in touch, but, in most other cases, they understood the pattern to be just a triangle or square as a result of bridging, without perceiving the contiguous surface. (2) Subjective depth was not observed so much even in vision by the naive subjects, although it was clear to the well-trained subjects. When depth displacement was reported, the subjective surface was perceived as more concave than the surface of paper. In conclusion, although the subjective-contour effect was confirmed in touch, it might be somewhat different from that of vision. It is still not clear if the perceived effect in touch is the result of the modal completion as it is in vision. [Work supported by the Ministry of Education, Science and Culture, No. 0310063.]