[A longitudinal study of the development of spatial problem solving ability in the early blinds]

To collect longitudinal data on the development of the spatial problem solving ability in the early blinds, 27 children of schools for the blind (8: 11 to 14: 11 years old), who participated in the Yamamoto's (1990) experiment two years ago, were re-tested using the same method as before. Five blind children (6: 3 to 7: 10 years) were also newly added. Subjects walked, with the guidance of the experimenter, on a route from the first to the third points. After reaching the third point of each route, subjects were required to walk back by him/herself to the first point. The trials were repeated 12 times using different routes. Subjects revealed less angle errors and less distance errors than in the previous experiment, but they did not show any change in the percentage of "longer turns" at the third pont. The subjects' trails of walking changed from the nonlinear to the linear types as a function of age. Differences in the three performance measures and the developmental changes in the walking-trails of children were discussed, the latter with reference to the developmental transition of the spatial ability from the route to the survey types.