Latin-American roots are neither discussed nor appreciated. While the families are matched on socioeconomic status, the sociocultural differences between them are considerable. In this example, the first child is bilingual and the second child is mono lingual, with the bilingual child having a higher IQ. The child's bilingualism may not be the only explanation of a higher IQ. Rather the alternative or additional explanation may be in the different social and cultural environment of these children. Thus, with Peal and Lambert's (1962) study, socioeconomic class may have been controlled, but not sociocultural class.