Do Bilinguals Acquire Similar Words to Monolinguals? An Examination of Word Acquisition and the Similarity Effect in Japanese-English Bilinguals' Vocabularies.

Previous research has paid much attention to the overall acquisition of vocabularies among bilingual children in comparison to their monolingual counterparts. Much less attention has been paid to the type of words acquired and the possible transfer or cross-linguistic effects of the other language on vocabulary development. Thus, this study aims to explore similarities and dissimilarities in the vocabularies of simultaneous bilinguals and Japanese monolinguals and considers the possible cross-linguistic similarity effect on word acquisition. Six simultaneous Japanese-English bilingual children (mean age = 34.75 months (2.56)) were language-age-matched with six Japanese monolinguals; their productive vocabularies were compared regarding size and categories. Additionally, characteristic acquired words were compared using correspondence analyses. Results showed that, although delayed due to the reduced inputs, young bilinguals have a similar set of vocabularies in terms of word category as monolinguals. However, bilingual children's vocabularies reflect their unevenly distributed experience with the language. Fewer interactive experiences with language speakers may result in a lower acquisition of interactive words. Furthermore, there is a cross-linguistic effect on acquisition, likely caused by form similarity between Japanese katakana words and English words. Even between languages with great dissimilarities, resources and cues are sought and used to facilitate bilingual vocabulary acquisition.

Learning to count begins in infancy: evidence from 18 month olds' visual preferences.

We used a preferential looking paradigm to evaluate infants' preferences for correct versus incorrect counting. Infants viewed a video depicting six fish. In the correct counting sequence, a hand pointed to each fish in turn, accompanied by verbal counting up to six. In the incorrect counting sequence, the hand moved between two of the six fish while there was still verbal counting to six, thereby violating the one-to-one correspondence principle of correct counting. Experiment 1 showed that Australian 18 month olds, but not 15 month olds, significantly preferred to watch the correct counting sequence. In experiment 2, Australian infants' preference for correct counting disappeared when the count words were replaced by beeps or by Japanese count words. In experiment 3, Japanese 18 month olds significantly preferred the correct counting video only when counting was in Japanese. These results show that infants start to acquire the abstract principles governing correct counting prior to producing any counting behaviour.

[Laterality of upper extremity movements in infancy: observations at 4 and 9 months of age].

This study investigated the process involved in the lateralization of movements during infancy by observing upper extremity movements in a laboratory setting. Reaching for flying rings, balls, mini toy cars, and small round cookies were observed and recorded by videotape at 4 and 9 months of age. The subjects were 202 infants who participated in Japan Children's Study, a cohort study on the development of sociability. Infants reached for objects significantly more frequently at 9 months (98%) than at 4 months (40%) (p<0.001). Though the lateral preference in reaching for balls at 4 months was ambiguous, reaching for toy cars was performed more frequently with the right hand at 9 months (50%) than with the left one (19%) (p<0.01). Lateralization of the upper extremity movements is thought to appear by 9 months.

Implications of social competence among thirty-month-old toddlers: a theory of mind perspective.

BACKGROUND: The purpose of this study was to examine the relations between children's social competence and initial index of theory of mind at 30 months of age. METHODS: The participants of the study were 322 toddlers and parents/caregivers who were registered with the Japan Science and Technology Agency (JST) project. They completed a five-minute interaction session, which was coded using the Interaction Rating Scale (IRS) as an evidence-based practical index of children's social competence. In addition, the children were asked to complete a diverse-desire task as a ToM (theory of mind) index. RESULTS: The results showed that the ToM index was related to the total score and subscales of the IRS, such as Empathy and Emotional regulation. CONCLUSIONS: These findings show that the IRS score was related to ToM task performance at 30 months of age.

Individual differences in changes in infants' interest in social signals in relation to developmental index.

Detection of social signals, such as biological motion and social causality, is of basic importance in early infancy. There have also been some accounts that infants' visual preference or reaction to social signals change during development because of their changing understanding of such signals, and the detective abilities of primary social signals are related to later social development. In this study, we attempted to find different developmental patterns in individuals in terms of their visual preference for biological motion and socially causal movements at 4, 9, and 18 months and 4 and 9 months, respectively, using a cluster analysis. It was found that for both types of social signals, the infants who demonstrated an increased interest in social stimuli at 9 months scored higher on the developmental index than those who showed a decrease, suggesting a difference in the quality of understanding of social signals at 9 months.

Development of infants' request expressions from 11 to 15 months.

Between 10 and 15 months of age, infants seem to become increasingly communicative. The focus of this study was changes in request behavior among infants at ages 11, 13, and 15 months (N = 22) in a longitudinal design. Changes in durations and frequencies of four different modes of behavior were examined, namely, use of hands, eye gaze, facial expression, and vocalization. Both frequencies and durations of the behaviors expressing requests increased with age, while those of nonrequest behaviors showed a different trend. Also investigated were changes in temporal coordination of different request modes. A greater number of infants used greater combinations of co-occurring modes when they were older than when they were younger.

[Infants' responses to the still-face situation at five and nine months: focusing on sex differences].

This study investigated developmental changes and sex differences in infants' responses to a female stranger during a face-to-face interaction, still-face, and reunion phase. Twenty-two infants (11 boys and 11 girls) were observed at five and nine months of age. At five months, the infants smiled less in the still-face phase, while at nine months the infants smiled less at each subsequent phase. Girls, but not boys, smiled more at nine months than five months. Girls' gazing toward the social partner's face decreased during the still-face and reunion phases. Girls gazed toward the social partner's face more than the boys, independent of the phases and age. The findings support the view the effect of a still-face on infants is robust at both five and nine months and for both sexes. But the effect remained in the reunion phase only for the nine-month-olds. These findings suggest that girls have more interest in their social partner than boys.