It is difficult for visually handicapped people to recognize spaces and their position in circular structures. They often have accidents or lose their way in such situations. In my previous studies, I found that they not only lost their way but also were not safe around circular structures. Therefore, I surveyed the spatial cognition of visually handicapped people walking outside circular structures. In this study, in order to clarify the spatial cognition of the visually handicapped and the characteristics of their search behavior, experiments were carried out by producing 4 kinds of model structures of circular plan. I chose 12 totally blind people ages 22 to 39 and 12 sleep mask wearers ages 18 to 24. I will call the sleep mask wearers s.m.w.
The results are as follows.
1. Walking speed of both the visually handicapped and the s.m.w. were 0.45m/s regardless of the radius when walking 1 lap, and this speed were 1.3 times of 1/4 laps. The rate of lap difference of the visually handicapped were 20-30 % and that of the s.m.w. were 30-45 %, regardless of the radius. Understanding of laps of the visually handicapped were 70-80 % and that of the s.m.w. were 50-70%. It appeared that the s.m.w. had difficulty understanding 3/4 laps. The larger the radius was, the smaller both the visually handicapped and the s.m.w. could sense the radius. They sensed the radius as 60-70% of the real radius in the 5m radius. The visually handicapped sensed the radius as 1.2 times of it in the 2m radius, while the s.m.w. sensed it correctly.
2. For the two, the difference of laps was correlated with the difference of the radius. The larger the difference of laps was, the larger the difference of the radius was, or the larger the difference of the radius was, the larger the difference of laps was. The regression line of the visually handicapped was similar to that of the s.m.w., so the relationship between the difference of laps and the difference of the radius had similar characteristics for the two.
3. When the visually handicapped sensed that they could understand the laps or they walked anticlockwise, the rate of the lap difference was lower and the difference of the radius was larger. When the s.m.w. sensed that they could understand the laps, the rate of the lap difference was higher and the difference of the radius was smaller, however the rate of the lap difference and the difference of the radius was not influenced by the direction they were walking. Depending on their understanding of laps and the walking direction, their consciousness turned to one side, and the understanding of laps and the cognition of the radius were not compatible.
4. As clues for the cognition of the laps, subjects sensed acoustic echo, imaging spaces, bending degrees of the wall and sense of rotation of their body useful, however degrees of panel seam, the number of panels and the number of steps not helpful. Moreover, the feeling of the panels was useful and also not helpful as a clue. When the subjects were walking around the circler structures, some of them were conscious of the center of the circle or the starting point constantly.
