Relationships between linguistic and behavioral measures during development

Forty-two children were assessed through the Galician adaptation of the MacArthur-Bates scales (IDHC) at 18 and 24 months of age, and spontaneous language measures were also obtained at the same ages. When the children were 48 months old, the Reynell Development of Language Scales, TOM tasks, and the WPPSI-R test were applied. Correlation and regression analyses were performed on these scores. Concurrent validity of the IDHC reached high values as measured through the correlations with spontaneous language measures. Predictive validity of the IDHC reached moderate values. IDHC vocabulary size at 24 months of age seemed to be a good predictor of later language development at 48 months, which in turn predicted TOM performance. An indirect effect of language at 24 months on TOM development is hypothesized.