Word-Learning Biases Contribute Differently to Late-Talker and Typically Developing Vocabulary Trajectories

This study explores how the vocabulary growth trajectories of typically developing and late-talker children change in relation to their word learning biases. Forty late talkers and 44 typically developing toddlers visited the lab once a month for one year starting at about 18 months of age. Word-learning trajectories were tracked using a parent-reported vocabulary measure, and shape and material bias measures were collected using the novel noun generalization task each month. A two-level hierarchical linear model was utilized for the longitudinal analyses. Results indicate that, at the first visit, a stronger shape bias was significantly associated with a larger vocabulary in typically developing talkers. In late talkers, however, a stronger initial shape bias was associated with a smaller vocabulary. Over the course of the study, for every additional visit, stronger shape biases were associated with larger vocabularies in late talkers, but not in typically developing toddlers. Results for the material bias mirrored the shape bias results. These findings suggest different possible underlying mechanisms for the two groups of children, as well as avenues for the design of language interventions that might support young late talkers

Bilingual and Monolingual Children Attend to Different Cues When Learning New Words

The way in which children learn language can vary depending on their language environment. Previous work suggests that bilingual children may be more sensitive to pragmatic cues from a speaker when learning new words than monolingual children are. On the other hand, monolingual children may rely more heavily on object properties than bilingual children do. In this study we manipulate these two sources of information within the same paradigm, using eye gaze as a pragmatic cue and similarity along different dimensions as an object cue. In the crucial condition, object and pragmatic cues were inconsistent with each other. Our results showed that in this ambiguous condition monolingual children attend more to object property cues whereas bilingual children attend more to pragmatic cues. Control conditions showed that monolingual children were sensitive to eye gaze and bilingual children were sensitive to similarity by shape; it was only when the cues were inconsistent that children’s preference for one or the other cue was apparent. Our results suggest that children learn to weigh different cues depending on their relative informativeness in their environment

On the Automatic Generation and Simplification of Children's Stories

With recent advances in large language models (LLMs), the concept of automatically generating children's educational materials has become increasingly realistic. Working toward the goal of age-appropriate simplicity in generated educational texts, we first examine the ability of several popular LLMs to generate stories with properly adjusted lexical and readability levels. We find that, in spite of the growing capabilities of LLMs, they do not yet possess the ability to limit their vocabulary to levels appropriate for younger age groups. As a second experiment, we explore the ability of state-of-the-art lexical simplification models to generalize to the domain of children's stories and, thus, create an efficient pipeline for their automatic generation. In order to test these models, we develop a dataset of child-directed lexical simplification instances, with examples taken from the LLM-generated stories in our first experiment. We find that, while the strongest-performing current lexical simplification models do not perform as well on material designed for children due to their reliance on large language models behind the scenes, some models that still achieve fairly strong results on general data can mimic or even improve their performance on children-directed data with proper fine-tuning, which we conduct using our newly created child-directed simplification dataset.Comment: Accepted to EMNLP 2023 (main conference

Reproducibility and a unifying explanation: Lessons from the shape bias

The goal of science is to advance our understanding of particular phenomena. However, in the field of development, the phenomena of interest are complex, multifaceted, and change over time. Here, we use three decades of research on the shape bias to argue that while replication is clearly an important part of the scientific process, integration across the findings of many studies that include variations in procedure is also critical to create a coherent understanding of the thoughts and behaviors of young children. The “shape bias,” or the tendency to generalize a novel label to novel objects of the same shape, is a reliable and robust behavioral finding and has been shown to predict future vocabulary growth and possible language disorders. Despite the robustness of the phenomenon, the way in which the shape bias is defined and tested has varied across studies and laboratories. The current review argues that differences in performance that come from even seemingly minor changes to the participants or task can offer critical insight to underlying mechanisms, and that working to incorporate data from multiple labs is an important way to reveal how task variation and a child’s individual pathway creates behavior—a key issue for understanding developmental phenomena

Learning from Word Books: Does the Type of Illustration Matter?

Picture books are a popular medium through which to promote language acquisition in young children. However, not much is known about how the pictorial context in which words are introduced in such books impacts word learning in toddlers, or how joint book reading further mediates this relationship. The present study introduced words to 19-23-month-old toddlers through books in either contextually rich, semantically relevant illustrations, or on a white background in isolation. Children and their parents participated in three lab visits during which a range of language and environmental measures were taken. Parents read our intervention materials at home between the first and second visits. We found that the pictorial context in which vocabulary words are presented was significantly related to language measures throughout our study. Further, this context also influences parents’ reading techniques, with longer interactions and more target words produced when reading contextually illustrated books. Our minimal book intervention shows promise in promoting vocabulary development in typically talking toddlers