A study of the responses made to problems selected from Raven's Progressive Matrices showed differences in the kinds of errors typically made by eighteen-year-old students. Nine problems were used and the 68 subjects were told to draw their answers on the answer sheets. There were two trials per puzzle. A classification system, devised for errors,…

This report discusses the relationship between bilingualism and mental development of bilingual children. After a review of the relevant literature, a specific study is described. The linguistic background of 648 children from 29 schools, age 10 through 12 inclusive, was measured with the Welsh Linguistic Background Scale. General intelligence was…