Assessing a continuum of lexical-semantic knowledge in the second year of life: A multimodal approach

Touching while listening: Does infants' haptic word processing speed predict vocabulary development?

The present study examined the links between haptic word processing speed, vocabulary, and inhibitory control among bilingual children. Three main hypotheses were tested: faster haptic processing speed, measured by the Computerized Comprehension Task at age 1;11, would be associated with larger concurrent vocabulary and greater longitudinal vocabulary growth. Second, early vocabulary size would be associated with greater vocabulary growth at 3;0 and 5;0. Finally, faster haptic processing speed would be associated with greater concurrent inhibitory control, as measured by the Shape Stroop Task. The results revealed that haptic processing speed was associated with concurrent vocabulary, but not predictive of later language skills. Also, early decontextualized vocabulary was predictive of vocabulary at 3;0. Finally, haptic processing speed measured in the non-dominant language was associated with inhibitory control. These results provide insight on the mechanisms of lexical retrieval in young bilinguals and expand previous research on haptic word processing and vocabulary development.

Convergence and divergence in prediction from vocabulary and speed of word processing

Toddler vocabulary knowledge and speed of word processing are associated with downstream language and cognition. Here, we investigate whether these associations differ across measures. At age two, 101 participants (55 monolingual French-speaking and 46 monolingual English-speaking children) completed a two-alternative forced choice task, yielding measures of decontextualized vocabulary (number of correct responses) and haptic speed of word processing (latency of correct responses). At ages three, four, and five children completed a battery of language assessments and an executive function task. Growth curve models revealed that age-two vocabulary significantly predicted age-three performance (but not growth from age three to four or four to five) across all language assessments but speed of processing did not predict language outcomes in final models. Finally, speed of processing was correlated with executive function at age three whereas vocabulary was not. Results suggest that vocabulary is associated with a range of downstream language abilities whereas haptic speed of processing may be associated with executive control.

When "shoe" becomes free from "putting on": The link between early meanings of object words and object-specific actions

Nouns referring to objects dominate children's early vocabulary over verbs referring to actions. However, some scholars have argued that early object-word meanings cannot be easily classified into specific object categories; rather, they have much undifferentiated meanings in which both objects and their specific actions are intertwined. We experimentally investigated this view using a two-alternative forced-choice task involving toddlers aged 18-23 months (n = 69). Both the cross-sectional and longitudinal results suggested that unlike older toddlers, younger ones could not select the correct referents when objects and object-specific actions were presented separately (e.g., "doing a filler action with shoes" vs. "putting on filler objects as if they were shoes") despite being successful when both were matched (e.g., "putting shoes on" vs. "doing a filler action with filler objects"). Additionally, toddlers failed to judge object-word referents solely by object-specific actions. These results indicated that early object-word meanings constitute the undifferentiated fusion of both objects and actions, and they subsequently differentiate into specific object categories independent of actions. Furthermore, the extent of such semantic differentiation is associated with the vocabulary growth of action words, suggesting that object-word meaning differentiation encouraged toddlers to develop new labels that could distinguish specific actions from objects. These findings revealed the uniqueness of young children's object-word comprehension, which is different from that of adults.

Looking represents choosing in toddlers: Exploring the equivalence between multimodal measures in forced-choice tasks

In the two-alternative forced-choice (2AFC) paradigm, manual responses such as pointing have been widely used as measures to estimate cognitive abilities. While pointing measurements can be easily collected, coded, analyzed, and interpreted, absent responses are often observed particularly when adopting these measures for toddler studies, which leads to an increase of missing data. Although looking responses such as preferential looking can be available as alternative measures in such cases, it is unknown how well looking measurements can be interpreted as equivalent to manual ones. This study aimed to answer this question by investigating how accurately pointing responses (i.e., left or right) could be predicted from concurrent preferential looking. Using pre-existing videos of toddlers aged 18-23 months engaged in an intermodal word comprehension task, we developed models predicting manual from looking responses. Results showed substantial prediction accuracy for both the Simple Majority Vote and Machine Learning-Based classifiers, which indicates that looking responses would be reasonable alternative measures of manual ones. However, the further exploratory analysis revealed that when applying the created models for data of toddlers who did not produce clear pointing responses, the estimation agreement of missing pointing between the models and the human coders slightly dropped. This indicates that looking responses without pointing were qualitatively different from those with pointing. Bridging two measurements in forced-choice tasks would help researchers avoid wasting collected data due to the absence of manual responses and interpret results from different modalities comprehensively.

Visual and haptic responses as measures of word comprehension and speed of processing in toddlers: Relative predictive utility

Early vocabulary knowledge and speed of word processing are important foundational skills for the development of preschool and school-age language and cognition. However, the variance in outcomes accounted for by parent-reported receptive or expressive vocabulary is generally modest. Recent research suggests that directly assessed, decontextualized vocabulary predicts developmental outcomes, including general language ability and kindergarten readiness, accounting for additional variance above and beyond parent-reported vocabulary. The current research extends this finding by exploring prediction from both decontextualized vocabulary and speed of word processing at 2 years of age to vocabulary during the preschool period. At age 2, children completed a two-alternative forced-choice task that yielded a measure of decontextualized vocabulary (number of correct touch responses) and two measures of speed of processing: latency to fixate the target (visual response latency) and latency to touch (haptic response latency). Results reveal that age 2 vocabulary and visual response latency, but not haptic response latency, independently predict vocabulary at ages 3 and 4. Furthermore, only decontextualized vocabulary remains a significant predictor when controlling for speed of processing, but not vice versa. This suggests that the number of early, stable word-referent associations and the efficiency with which these are processed are important to vocabulary outcomes. However, it also suggests that decontextualized vocabulary may be a more robust unique predictor of downstream outcomes.

Language status at age 3: Group and individual prediction from vocabulary comprehension in the second year

The present research extends recent work on the prediction of preschool language skills by exploring prediction from decontextualized vocabulary comprehension. Vocabulary comprehension was a stronger predictor than parent-reported production, yielding a quadrupling of variance accounted for relative to prior studies. Parallel studies (Studies 1 and 2) are reported for two linguistically and geographically distinct samples. In both samples, decontextualized vocabulary comprehension late in the second year provided the best balance between model fit and parsimony in predicting language skills at age three. In Study 3, vocabulary comprehension prospectively identified children with low language status 2 years earlier than other prospective studies but with similar sensitivity and specificity. The present paper provides evidence on three questions of practical and theoretical significance: the relation between decontextualized vocabulary prior to 30 months of age and language outcomes, how prediction from decontextualized vocabulary compares with parent-reported vocabulary, and finally how early stable predictions to language outcomes can be made. (PsycINFO Database Record (c) 2018 APA, all rights reserved).