Visual variability affects early verb learning

Becoming word meaning experts: Infants' processing of familiar words in the context of typical and atypical exemplars

How do infants become word meaning experts? This registered report investigated the structure of infants' early lexical representations by manipulating the typicality of exemplars from familiar animal categories. 14- to 18-month-old infants (N = 84; 51 female; M = 15.7 months; race/ethnicity: 64% White, 8% Asian, 2% Hispanic, 1% Black, and 23% multiple categories; participating 2022-2023) were tested on their ability to recognize typical and atypical category exemplars after hearing familiar basic-level category labels. Infants robustly recognized both typical (d = 0.79, 95% CI [0.54, 1.03]) and atypical (d = 0.70, 95% CI [0.46, 0.94]) exemplars, with no significant difference between typicality conditions (d = 0.14, 95% CI [-0.08, 0.35]). These results support a broad-to-narrow account of infants' early word meanings. Implications for the role of experience in the development of lexical knowledge are discussed.

Combining Languages in Bilingual Input: Using Experimental Evidence to Formulate Bilingual Exposure Strategies

PURPOSE

Traditional approaches to studying bilingual language development through bilingual-monolingual comparisons are deeply flawed. They are also insufficient as the evidence base for informing advice to bilingual parents regarding the optimal bilingual exposure strategy and for supporting the formulation of bilingual intervention approaches. The purpose of this review article is to provide an overview of empirical studies that have queried the question of how different types of dual-language input shape learning and language outcomes in bilingual children.

METHOD

We rely on tightly controlled experimental studies of word learning in Spanish-English bilingual children, where we contrast children's learning in dual-language conditions (defined as distributed exposure and code-switched input) to a single-language condition in a within-subjects design.

RESULTS

Word-learning studies querying the role of distributed exposure indicated that distribution of exposures across Spanish and English reduced children's performance in comparison to English-only exposure. However, this effect was rooted in the abrupt switch from Spanish to English rather than distributed exposure itself. In contrast, an experiment designed to test the role of code-switched context on children's word learning revealed that code-switched context where switches resembled naturalistic code-switching behaviors enhanced learning in Spanish-English bilingual children. Notably, across different studies, children with weaker language skills (developmental language disorder) were no more affected by dual-language input than children with typical language skills.

CONCLUSIONS

Together, experimental studies of word learning indicate that bilingual children can effectively learn from dual-language input but that different ways of combining languages in the input to bilingual children can have distinct consequences for learning. Ultimately, word-learning experiments, beyond answering critical questions regarding bilingual learning, can serve as an effective bridge between laboratory-based work and intervention studies whose goal it is to discover the optimal way of combining languages in the input to bilingual children with communication impairments.

PRESENTATION VIDEO

https://doi.org/10.23641/asha.23929515.

Association between Visual Perception and Socioeconomic Status in Malaysian Preschool Children: Results from the Test of Visual Perceptual Skills-4

Visual perception in children can be evaluated using the Test of Visual Perceptual Skills-4th edition (TVPS-4) with normative data developed for the U.S. population. It is widely used by healthcare practitioners in Malaysia, despite reports that children in Asia outperform their U.S. peers in visual perception assessment. We compared TVPS-4 scores among 72 Malaysian preschool children (mean age: 5.06 ± 0.11 years) with U.S. norms and investigated the association between socioeconomic factors and TVPS-4 scores. Malaysian preschoolers had significantly higher standard scores (116.60 ± 7.16) than the U.S. norms (100 ± 15; p < 0.001). They also had significantly higher scaled scores (between 12.57 ± 2.10 and 13.89 ± 2.54) than the U.S. norms (10 ± 3, all p < 0.001) for all subtests. Multiple linear regression analyses revealed that socioeconomic variables were not significant predictors for five visual perception subtests and the overall standard score. The visual form constancy score could be predicted by ethnicity (β = -1.874, p = 0.03). The visual sequential memory score could be predicted by the father's employment status (β = 2.399, p < 0.001), mother's employment status (β = 1.303, p = 0.007), and low household income (β = -1.430, p < 0.037). In conclusion, Malaysian preschoolers outperformed their U.S. peers in all TVPS-4 subtests. Socioeconomic variables were associated with visual form constancy and visual sequential memory, but not with the other five subtests or TVPS-4's overall standard scores.

Does code-switching influence novel word learning?

Code-switching occurs regularly in the input to bilingual children. Yet, the effect of code-switched input on language development is unclear. To test whether word learning would be affected by code-switching, Spanish-English bilingual children (N = 45, 19 boys, Mean_Age  = 5.05 years; ethnicity: 37 Hispanic/Latino, six Non-Hispanic/Latino, two unreported) were taught English-like novel words in two conditions. In the English-only condition, definitions for novel words were provided entirely in English. In the code-switch condition, definitions for novel words were provided in English and Spanish, incorporating code-switches. Children required fewer exposures to retain novel words in the code-switch than the English-only condition and this effect was not moderated by children's language ability or exposure to code-switching, suggesting that code-switched input does not pose word-learning risks to bilingual children, including children with lower levels of language ability.

Can children learn verbs from events separated in time? Examining how variability and memory contribute to verb learning

Children in everyday environments experience verbs separated by minutes or hours and linked to events that vary in their similarity. Prior studies have shown that seeing similar events can be beneficial for verb learning (e.g., complex events), but there is also evidence that varied events or seeing both similar and varied events is useful; more studies are needed. In addition, few prior verb studies have tested verb learning from spaced practice. In Study 1, 3½- and 4½-year-olds (N = 72) saw either three similar events, three varied events, or a single live event (control) while hearing a new verb; events were separated by 1-min delays. Results showed better performance in multiple-event conditions than in the single-event condition and showed more extensions with age. Specifically, children benefitted more from seeing varied events with age. In Study 2, 2½-, 3½-, and 4½-year-olds (N = 163) either saw similar and then varied events or saw all varied video events separated by 1-min delays or no delays. The youngest children performed significantly better in the similar first condition than in the all varied condition, showing the first evidence of this benefit following spaced practice. In addition, as in Study 1, performance after seeing varied events increased with age. Together, these studies show that children can compare events separated in time and that their ability to learn verbs from varied examples develops with age.

The role of semantic similarity in verb learning events: Vocabulary-related changes across early development

Verb meaning is challenging for children to learn across varied events. This study examined how the taxonomic semantic similarity of the nouns in novel verb learning events in a progressive alignment learning condition differed from the taxonomic dissimilarity of nouns in a dissimilar learning condition in supporting near (similar) and far (dissimilar) verb generalization to novel objects in an eye-tracking task. A total of 48 children in two age groups (23 girls; younger: 21-24 months, Mage = 22.1 months; older: 27-30 months: Mage = 28.3 months) who differed in taxonomic vocabulary size were tested. There were no group or learning condition differences in near generalization. The younger group demonstrated better far generalization of verbs learned with semantically dissimilar nouns. The older group demonstrated the opposite pattern, with better far generalization of verbs learned with semantically similar nouns in the progressive alignment condition. These patterns were associated with children's in-category vocabulary knowledge more than other vocabulary measures, including verb vocabulary size. Taxonomic vocabulary knowledge differentially affects verb learning and generalization across development.

Repetition Versus Variability in Verb Learning: Sometimes Less Is More

Purpose This study examined whether 2-year-olds are better able to acquire novel verb meanings when they appear in varying linguistic contexts, including both content nouns and pronouns, as compared to when the contexts are consistent, including only content nouns. Additionally, differences between typically developing toddlers and late talkers were explored. Method Forty-seven English-acquiring 2-year-olds (n = 14 late talkers, n = 33 typically developing) saw scenes of actors manipulating objects. These actions were labeled with novel verbs. In the varied condition, children heard sentences containing both content nouns and pronouns (e.g., "The girl is ziffing the truck. She is ziffing it!"). In the consistent condition, children heard the verb an equal number of times, but only with content nouns (e.g., "The girl is ziffing the truck. The girl is ziffing the truck!"). At test, children were shown two new scenes and were asked to find the novel verb's referent. Children's eye gaze was analyzed as a measure of learning. Results Mixed-effects regression analyses revealed that children looked more toward the correct scene in the consistent condition than the varied condition. This difference was more pronounced for late talkers than for typically developing children. Conclusion To acquire an initial representation of a new verb's meaning, children, particularly late talkers, benefit more from hearing the verb in consistent linguistic contexts than in varying contexts.

Kinematic boundary cues modulate 12-month-old infants' segmentation of action sequences: An ERP study

Human infants can segment action sequences into their constituent actions already during the first year of life. However, work to date has almost exclusively examined the role of infants' conceptual knowledge of actions and their outcomes in driving this segmentation. The present study examined electrophysiological correlates of infants' processing of lower-level perceptual cues that signal a boundary between two actions of an action sequence. Specifically, we tested the effect of kinematic boundary cues (pre-boundary lengthening and pause) on 12-month-old infants' (N = 27) processing of a sequence of three arbitrary actions, performed by an animated figure. Using the Event-Related Potential (ERP) approach, evidence of a positivity following the onset of the boundary cues was found, in line with previous work that has found an ERP positivity (Closure Positive Shift, CPS) related to boundary processing in auditory stimuli and action sequences in adults. Moreover, an ERP negativity (Negative Central, Nc) indicated that infants' encoding of the post-boundary action was modulated by the presence or absence of prior boundary cues. We therefore conclude that 12-month-old infants are sensitive to lower-level perceptual kinematic boundary cues, which can support segmentation of a continuous stream of movement into individual action units.

Category structure guides the formation of neural representations

Perceptual variability is often viewed as having multiple benefits in object learning and categorization. Despite the abundant results demonstrating benefits such as increased transfer of knowledge, the neural mechanisms underlying variability as well as the developmental trajectories of how variability precipitates changes to category boundaries are unknown. By manipulating an individual's exposure to variability of novel, metrically organized categories during an fMRI-adaptation paradigm, we were able to assess the functional differences between similarity and variability in category learning and generalization across two time-points in development: adulthood (n = 14) and late childhood (n = 13). During this study, participants were repeatedly exposed to category members from different distributions. After a period of adaptation, a deviant stimulus that differed from the expected distribution was then presented. This deviant differed in either an invariant dimension (a feature that remained consistent throughout presentation was altered) or a similarity dimension (a feature that changed throughout exposure was changed in a new dimension). Our results can be summarized in three main findings: (1) Variability during exposure recruited the right fusiform gyrus to a greater extent than tight exposure. (2) Deviant items were generalized based on the exemplar distributions during exposure, although children only generalized items if provided variable exposure. (3) Variability influenced release to a greater extent in children than adults. These results are discussed in relation to the variability and category learning literature more broadly.

Visual experiences during letter production contribute to the development of the neural systems supporting letter perception

Letter production through handwriting creates visual experiences that may be important for the development of visual letter perception. We sought to better understand the neural responses to different visual percepts created during handwriting at different levels of experience. Three groups of participants, younger children, older children, and adults, ranging in age from 4.5 to 22 years old, were presented with dynamic and static presentations of their own handwritten letters, static presentations of an age-matched control's handwritten letters, and typeface letters during fMRI. First, data from each group were analyzed through a series of contrasts designed to highlight neural systems that were most sensitive to each visual experience in each age group. We found that younger children recruited ventral-temporal cortex during perception and this response was associated with the variability present in handwritten forms. Older children and adults also recruited ventral-temporal cortex; this response, however, was significant for typed letter forms but not variability. The adult response to typed letters was more distributed than in the children, including ventral-temporal, parietal, and frontal motor cortices. The adult response was also significant for one's own handwritten letters in left parietal cortex. Second, we compared responses among age groups. Compared to older children, younger children demonstrated a greater fusiform response associated with handwritten form variability. When compared to adults, younger children demonstrated a greater response to this variability in left parietal cortex. Our results suggest that the visual perception of the variability present in handwritten forms that occurs during handwriting may contribute to developmental changes in the neural systems that support letter perception.

Optimal Contexts for Verb Learning

Purpose

Verb learning is a critical but challenging part of language acquisition. Children with or at increased risk for developmental language disorder (DLD) may particularly struggle with verb learning, and poor verb representations in turn may negatively impact children's language outcomes. Our goal is to examine literature on children's acquisition of verbs, identifying manipulable factors that may determine the ease or difficulty of acquiring a new verb meaning.

Method

In this narrative, non-systematic review, we discuss findings about how verbs are learned and represented.

Results

Several aspects of the learning environment affect children's efforts to acquire verbs, including the linguistic context in which the verb is introduced, the timing of the linguistic label relative to the event it describes, visual and linguistic variability, and dose frequency.

Conclusions

We conclude that some learning situations are likely to be more helpful for children in the process of verb learning than others. We highlight some of the factors that contribute to good learning situations, and we discuss how these may differ depending on properties of the child and of the verb itself. Finally, we propose hypotheses for future translational and clinical research.

Validity and Reliability of the Developmental Test of Visual Perception - Third Edition (DTVP-3)

The Developmental Test of Visual Perception - Third Edition (DTVP-3) is a recently published revision of a visual perceptual test from the United States, frequently used by occupational therapists. It is important that tests have adequate documented reliability and validity and are evaluated in cross-cultural contexts. The purpose of the study was to assess the reliability and validity of the DTVP-3 when completed by a group of Australian participants. Thirty-nine typically developing children 6-8 years of age completed the DTVP-3 and the Developmental Test of Visual-Motor Integration - 6th edition (VMI-6). The internal consistency of the DVTP-3 was assessed using Cronbach alpha coefficients and the DTVP-3's convergent validity was examined by correlating it with the VMI-6 and its two supplementary tests. The five DTVP-3 subscales' Cronbach alpha coefficients ranged from.60 to.80 while its three composite indexes had coefficients all at the.80 level. The VMI-6 was significantly correlated with the DTVP-3 Figure Ground and Visual Closure subscales and the Motor-Reduced Visual Perception Index (MRVPI). The VMI-6 Visual Perception Supplementary Test was significantly correlated with the DTVP-3 Figure Ground, Visual Closure, Form Constancy, MRVPI, and General Visual Perception Index. The DTVP-3 exhibited acceptable levels of internal consistency and moderate levels of convergent validity with the VMI-6 when completed by a group of Australian children.

Handwriting generates variable visual output to facilitate symbol learning

Recent research has demonstrated that handwriting practice facilitates letter categorization in young children. The present experiments investigated why handwriting practice facilitates visual categorization by comparing 2 hypotheses: that handwriting exerts its facilitative effect because of the visual-motor production of forms, resulting in a direct link between motor and perceptual systems, or because handwriting produces variable visual instances of a named category in the environment that then changes neural systems. We addressed these issues by measuring performance of 5-year-old children on a categorization task involving novel, Greek symbols across 6 different types of learning conditions: 3 involving visual-motor practice (copying typed symbols independently, tracing typed symbols, tracing handwritten symbols) and 3 involving visual-auditory practice (seeing and saying typed symbols of a single typed font, of variable typed fonts, and of handwritten examples). We could therefore compare visual-motor production with visual perception both of variable and similar forms. Comparisons across the 6 conditions (N = 72) demonstrated that all conditions that involved studying highly variable instances of a symbol facilitated symbol categorization relative to conditions where similar instances of a symbol were learned, regardless of visual-motor production. Therefore, learning perceptually variable instances of a category enhanced performance, suggesting that handwriting facilitates symbol understanding by virtue of its environmental output: supporting the notion of developmental change though brain-body-environment interactions. (PsycINFO Database Record

Vocabulary Instruction on Sesame Street: A Content Analysis of the Word on the Street Initiative

PURPOSE

Authors of this content analysis examined how Sesame Street's Word on the Street initiative aligns with research-based practices for selecting and teaching vocabulary to young children and considered how speech-language pathologists can use educational media to supplement traditional vocabulary instruction.

METHOD

Study authors used a well-established vocabulary selection hierarchy to analyze 170 target words across 7 seasons of Word on the Street to judge appropriateness for preschool vocabulary instruction. The authors then coded vocabulary instruction across 96 episodes to determine frequency and types of teaching strategies used within this educational program.

RESULTS

Target word selection was appropriate in 77% of episodes. Some instructional strategies were used frequently (e.g., exposure to a word, examples, and nonexamples), whereas others were used rarely (e.g., definitions, active learning). Across episodes, there was substantial variability in how many opportunities children had to learn words.

CONCLUSIONS

Vocabulary instruction during Word on the Street could be improved by targeting only high-utility words, maximizing learning opportunities during all segments, and increasing strategies that promote deep processing. Although research is needed to examine word learning during Word on the Street, speech-language pathologists may find selected segments targeting Tier 2 words useful for augmenting traditional intervention approaches.