The development of the concept of conservation was examined in 120 elementary school children divided into three groups: partially sighted, sighted, and sighted-blindfolded. (CM)

Through seriation, verbal seriation, and conservation tasks, investigated blind, partially sighted, and sighted children's understanding of quantity. Subjects were 81 children equally dispersed through these 3 groups. Age range was 4 to 17 years. Found similarity in concept acquisition among three groups that extended beyond quantity conservation…