Language Acquisition in Childhood
Bornstein, Hahn, Haynes, Painter
The acquisition of language constitutes one of the most remarkable and complex achievements of early childhood. As part of its domestic longitudinal work , the CFRS undertook several studies to examine parameters of children’s language acquisition and the centrality of maternal responsiveness in the process. One study compared naturalistic samples of three features of language in two-year-olds (total utterances, word roots, and mean length of utterance [MLU]) in the home in three contrasting situations: the child observed playing by her/himself with mother nearby, the child and mother observed in direct play interaction, and the child and mother unobserved at a time the mother judged would provide a sample of the child’s “optimal” language. Children produced more utterances and word roots and expressed themselves in longer MLU when in interaction than when playing “alone,” but children’s utterances, word roots, and MLU were greatest in the “optimal” language production situation. Girls used more word roots and spoke in longer MLU than boys. Despite mean level differences, children maintained their rank orders across the three situations in use of word roots and in MLU. These findings have implications for understanding children’s language and the degree to which this type of sampling represents child language. Three longitudinal studies assessed stability of language performance cumulatively from one to seven years. Data were drawn from maternal questionnaires, maternal interviews, experimenter assessments, and teacher reports. Language performance at each age and stability across age in girls and boys were assessed separately and together. Across age, including the important transition from preschool to school, across multiple tests at each age, and across multiple reporters, children showed moderate to strong stability of individual differences; stability did not differ between girls and boys. In the second through fifth years but not before or after, girls consistently outperformed boys in lexical knowledge and use. Further investigations revealed that mothers varied substantially in the quality and quantity of language they provided to their children. When both language amount and verbal responsive-ness were considered, however, verbal responsiveness was found to contribute uniquely to children’s emerging language. Children with verbally responsive mothers achieved the vocabulary spurt and combined words into simple sentences sooner in development than did children with less verbally responsive mothers. These predictive associations between responsiveness and the timing of children’s language milestone were more robust at 13 than at nine months. The best fitting model of language acquisition was one that included both children’s and mothers’ contributions: That is, a child who produced first words sooner in development, coupled with a verbally responsive mother, was at a strong advantage for precocious achievement of key language milestones.

Family and Child Acculturation in Modern America
Bornstein, Cote, Suwalsky
We examined the process of acculturation similarities and differences in mothers’ and infants’ activities and interactions among Japanese American and South American dyads. Few relations between maternal acculturation level or individualism/collectivism and maternal parenting or infant behaviors emerged in either group. However, group differences were found in mothers’ and infants’ behaviors, indicating that culture-of-origin continues to influence parenting behavior in acculturating groups. Further analysis revealed few relations among mothers’ behaviors, except those that reflect the common collectivist orientation of the two cultural groups. Few relations among infants’ behaviors emerged, suggesting independence and plasticity in infant behavioral organization. Relations between mothers’ and infants’ behaviors pointed to universal characteristics in mother-infant interactions. Continuity, stability, and difference in cultural cogni-tions (acculturation, individualism, collectivism) and parenting cognitions (attributions, self-perceptions, and knowledge) were then evaluated. South American mothers were more collectivist than Japanese American mothers. Cultural group and attribution differences emerged for mothers’ attributions in successful situations, whereas child age and attribution differences emerged for attributions in unsuccessful situations. Japanese American mothers’ feelings of competence increased over time. South American mothers reported a higher degree of satisfaction with the parenting role than Japanese American mothers. Mothers’ cultural cognitions and parenting cognitions were largely stable, although more so for Japanese American than South American mothers. Finally, patterns of covariation and coherence among mothers’ cultural and parenting cognitions were assessed. Few relations between cultural and parenting cognitions emerged, and those that did were limited primarily to South American mothers with infants at five months and Japanese American mothers with toddlers at 20 months. Coherence among cultural cognitions was found for South American mothers with a child at 20 months. Coherence among mothers’ attributions and among their perceptions of their own parenting was found for both Japanese American and South American mothers with children at both five and 20 months. Relations across types of parenting cognitions were also found (i.e., self-perceptions were related to both attributions and knowledge of parenting), but for the most part these domains of parenting cognitions appeared to be relatively independent.

Another analysis explored the influence of acculturation on multiple parenting beliefs in two cultural comparisons: Japanese, Japanese American, and European American mothers; and Argentine, South American, and European American mothers. Several attributions for successful parenting increased linearly with acculturation in both cultural comparisons; other attributions for unsuccessful parenting increased in a quadratic fashion in the South American comparison. Some linear and some quadratic trends were found for mothers’ parenting self-perceptions in the Japanese comparison; fewer trends were found in the South American comparison. Linear trends emerged for mothers’ knowledge of childrearing and child development in both cultural comparisons. Fewer linear relations between acculturation and parenting beliefs emerged at the individual than at the group level.

Nutrition and Development in Early Childhood
Bornstein
To evaluate the effects of dietary intake of the long-chain polyunsaturated fatty acids, arachidonic acid (AA) and docosahexaenoic acid (DHA), on multiple indices of infant growth and development, a double-masked, randomized, parallel trial was conducted with term infants fed formulas with or without AA+DHA for one year. Reference groups of breastfed infants weaned to formulas with and without AA+DHA were also studied. The main study outcomes were AA and DHA levels in plasma and red blood cells and multiple measures of infant development at multiple ages from birth to 14 months: growth, visual acuity, information processing, general development, language, and temperament. AA and DHA levels in plasma and red cells were higher in AA+DHA supplemented groups than in the control formula group and comparable to those in reference groups. No developmental test results distinguished these groups. Expected differences in family demographics associated with breastfeeding were found, but no advantages to breastfeeding on any of the developmental outcome were demonstrated. The findings do not support adding AA+DHA to formulas containing 10 percent energy as linoleic acid and 1 percent energy as _-linolenic acid to enhance growth, visual acuity, information processing, general development, language, or temperament in healthy, term infants in the first year following birth.

Psychophysiological Bases of Mental and Emotional Functioning in Childhood
Bornstein, Haynes
In a prospective longitudinal study, vagal tone and heart period were measured twice, at two months and at five years, in both children and their mothers to evaluate and compare the development of the vagal system and its regulatory capacity at rest and during an environmental task. Child baseline vagal tone and heart period were discontinuous; mother baseline vagal tone was discontinuous, but heart period was continuous. The group mean baseline-to-task change in vagal tone and heart period were continuous in both children and mothers. Children reached adult levels of baseline vagal tone by five years, and children and their mothers did not differ in the baseline-to-task change in vagal tone or heart period. Baseline vagal tone tended to be stable, but baseline heart period and the baseline-to-task change in vagal tone and heart period were unstable in children; both were stable in mothers. The baseline-to-task change in vagal tone showed consistent child-mother concordance. A second study investigated the role of cardiac vagal tone in information processing (habituation) in infants. Nucleus ambiguous vagal tone (Vna) was used to index cardiac vagal tone. Physiological self-regulation was operationalized as the change in Vna from a baseline period of measurement to habituation. Decreases in Vna consistently related to habituation efficiency, operationalized as accumulated looking time (ALT), in all infants twice at two months and twice at five months; however, this relation was accounted for by infants who met a habituation criterion on each task. Among habituators, shorter lookers also had greater Vna suppression during habituation. Within-age and between-age suppression of vagal tone predicted ALT, but ALT did not predict suppression of vagal tone. Physiological self-regulation provided by the vagal system appears to play a role in information processing in infancy as indexed by habituation.