Studies the sequence in development of conservation concepts in 19 language-impaired children aged 6-9 years and 20 children of 3-11 years who had no impairment. The two groups showed a similar sequence of development regardless of delay. Conservation of number appeared first, followed by weight, substance, length, area, and volume. (RJC)

Investigated the cognitive development of children with emotional and behavioral difficulties (EBDs). Found that children with EBDs showed a similar order of acquisition of conservation as normal children, and the thinking of children with EBDs was characterized by a high degree of uncertainty. (BC)

Investigates the development of understanding of quantity in 36 children with Down's Syndrome. Findings confirmed similarities in sequence of development between Down's Syndrome children and nonretarded children. Down's children who received training recognized conservation of continuous and discontinuous quantity. (RJC)

Investigates the extent of similarity in the sequence of development of concepts in children with Down's Syndrome, children with other forms of retardation, and nonretarded children. (Author/BB)

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…