Cognitive development of Chinese urban only children and children with siblings

142 first- and 188 fifth-grade only children and children with siblings from the Beijing area were given 11 cognitive tasks to investigate the difference in cognitive abilities that may exist due to the special conditions resulting from the Chinese 1-child family planning program. Overall superiority of grade 1 only children over children with siblings appeared in cognitive abilities involving memory processes, language skills, and mathematics. No differences existed for perceptual tasks. However, the differences in cognitive abilities between only children and children with siblings at grade 5 were less prominent than at grade 1. The cognitive superiority of these younger Chinese only children over children with siblings may be explained by the fact that the fifth-grade only children were born before 1980 when the 1-child family planning program was not strongly enforced. Parents may have tended to treat these children and children with siblings alike. In contrast, the first-grade only children were born at a time of government policy intervention that resulted in special investment in these children by parents and elders, suggesting the possibility of a time-related cohort effect.