Planar asymmetry tips the phonological playground and environment raises the bar

Reading readiness varies as a function of family and environmental variable s. This study of Ii-year-old children (N = 39) was designed to determine if there was an additional or interactive contribution of brain structure. Ev idence is presented that both environmental and biological variables predic t phonological development. Temporal lobe (planar) asymmetry, hand preferen ce, family history of reading disability, and SES explained over half of th e variance in phonological and verbal performance. The results demonstrate a linear association between cerebral organization and phonological skill w ithin socioeconomic groups. These data provide concrete evidence to support the commonly held assumption that both environmental and biological factor s are independent determinants of a child's ability to profess linguistic i nformation.