Language acquisition in a multilingual society: English vocabulary norms and predictors in Singaporean children.

In this study, infant vocabulary development was tracked in a multilingual society (Singapore) within a socioeconomically diverse sample. The sample comprised 1316 infants from 17.4 to 27.7 months (669 females, 647 males; 88% Chinese race, 4% Malay, 4% Indian, and 0.004% mixed-race [4% declined to provide race information]). Children varied in English language exposure and socioeconomic status. Analyses focused on identifying demographic predictors of English vocabulary size in multilingually exposed infants. Adaptations of the Macarthur-Bates Communicative Development Inventory for English, Mandarin, and Malay are provided as well as English vocabulary norms that account for variation in English exposure. This manuscript reports the first set of English language norms-calibrated to English exposure-for multilingual infants in a non-Western setting.

Becoming more or less mature? The decline of self-control in middle childhood.

OBJECTIVE: This study examined the developmental change in self-control and its association with daily stressful events during middle childhood, as well as the factors that contribute to individual differences in the trajectory of self-control. METHOD: A community sample of 302 Singaporean children (42% female, 69% Chinese) and their parents were recruited when the children were age 7. Follow-up assessments were made when the children were ages 8, 9, and 11. Developmental changes were examined using latent growth and autoregressive cross-lagged models. RESULTS: Self-control showed a normative decline over time, and this trajectory was associated with an increase in daily stressful events. There was partial evidence for a reciprocal relationship between self-control and daily stressful events over time. Moreover, the child temperament dimension of effortful control (assessed at age 7) mitigated the decline in self-control, whereas low socioeconomic status predicted lower initial levels of self-control. CONCLUSIONS: This study advances current understanding on the developmental change in self-control during middle childhood, as well as the factors that shape the direction and magnitude of this change.

Developmental Trajectories of Maladaptive Perfectionism in Middle Childhood.

The developmental trajectories of maladaptive perfectionism, along with their consequences and origins, were examined in middle childhood. A sample of Singaporean children and their parents (N = 302) were recruited for a longitudinal study when the children were 7 years old. Subsequent follow-up assessments were made at ages 8, 9, and 11. A multimethod approach was adopted where parent reports, child reports, and observational data on a dyadic interaction task were obtained. Using latent class growth modeling, four distinct classes were obtained for critical self-oriented perfectionism (SOP-C), whereas two classes emerged for socially prescribed perfectionism (SPP). Children with high and/or increasing SOP-C and SPP trajectories constituted 60% and 78% of the sample, respectively. For both SOP-C and SPP, trajectories with high initial status were associated with higher internalizing and externalizing symptoms. Parental intrusiveness and negative parenting predicted high and/or increasing SOP-C trajectories, whereas the child temperament dimension of surgency predicted high SPP trajectory. Both SOP-C and SPP trajectories tended to co-occur, suggesting a mutually reinforcing process. This study yields important findings that help advance current understanding of the emergence and developmental pathways of maladaptive perfectionism in children.

Observing neighborhood effects without neighbors.

With a new metric called phonological Levenshtein distance (PLD20), the present study explores the effects of phonological similarity and word frequency on spoken word recognition, using polysyllabic words that have neither phonological nor orthographic neighbors, as defined by neighborhood density (the N-metric). Inhibitory effects of PLD20 were observed for these lexical hermits: Close-PLD20 words were recognized more slowly than distant PLD20 words, indicating lexical competition. Importantly, these inhibitory effects were found only for low- (not high-) frequency words, in line with previous findings that phonetically related primes inhibit recognition of low-frequency words. These results indicate that the properties of PLD20--a continuous measure of word-form similarity--make it a promising new metric for quantifying phonological distinctiveness in spoken word recognition research.

Distributional analyses in auditory lexical decision: neighborhood density and word-frequency effects.

In the present article, the effects of phonological neighborhood density and word frequency in spoken word recognition were examined using distributional analyses of response latencies in auditory lexical decision. A density x frequency interaction was observed in mean latencies; frequency effects were larger for low-density words than for high-density words. Distributional analyses further revealed that for low-density words, frequency effects were reflected in both distributional shifting and skewing, whereas for high-density words, frequency effects were purely mediated by distributional skewing. The results suggest that word frequency plays a role in early auditory word recognition only when there is relatively little competition between similar-sounding words, and that frequency effects in high-density words reflect postlexical checking.

Flexible and context-dependent categorization by eighteen-month-olds.

One hundred 18-month-olds were tested using sequential touching and following 4 different priming contexts using sets of toys that could be simultaneously categorized at either the basic or global level. An exact expression of the expected mean sequence length for arbitrary categories was derived as a function of the number of touches made, and a finite mixture model analytic method was also used to explore individual variability in categorization. Toddlers could categorize flexibly and spontaneously selected the level of categorization as a function of the prior prime. Perceptual Variability emerged as a predictor of the level at which infants subsequently categorized. The infants were also able to classify objects as members of both basic- and global-level categories simultaneously.