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.

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.

[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.

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.

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.

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.

[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.