Abstract
The development of young children's mobility and two functions of the use of landmarks, i.e. 1) the setting up of the sequential comprehension of space (positive effect of landmarks) and 2) the disturbance of the comprehensive understanding of space (negative effect of landmarks), were investigated. Twenty 2: 9 and 3: 10 years old children experienced a route made of three large boxes, then they were required to reverse and to detour the route. It was considered that the sequential comprehension was necessary for solving the reversal task, and the comprehensive understanding was necessary for solving the detour task. Half of the subjects passed the route with remarkable landmarks. Six 1: 11 years old children were also added in this experiment. The results showed that landmarks improved subject's performance in the reversal task and had no effect on the detour task ; performances in both tasks were developed. Analysis for the course walked by subjects showed negative effect of landmarks. Development of young children's spatial ability and the cause of its negative effects were discussed.
