Piaget and Inhelder, in The Child's Conception of Space (1956), described the coordination of viewpoints (CV) spatial operation as one of the prerequisites to the development of the rotation and development (RD) spatial operation. This study investigated this developmental dependency notion and also evaluated the effects of age and sex on the development of the CV and RD operations. Two 16-item instruments, one for each operation, were administered individually to 112 children, eight females and eight males at seven age levels, 7 through 13. In contrast to Piaget's and Inhelder's writings, the data revealed that some of the components of an RD operation seem to be among the major prerequisites to the development of the CV operation. Further analysis indicated that the capacity for CV and RD operational functioning appear to be greater in older children than in younger children and greater in males than in females. (Author)