Vocabulary and automatic attention: The relation between novel words and gaze dynamics in noun generalization.

Words direct visual attention in infants, children, and adults, presumably by activating representations of referents that then direct attention to matching stimuli in the visual scene. Novel, unknown, words have also been shown to direct attention, likely via the activation of more general representations of naming events. To examine the critical issue of how novel words and visual attention interact to support word learning we coded frame-by-frame the gaze of 17- to 31-month-old children (n = 66, 38 females) while generalizing novel nouns. We replicate prior findings of more attention to shape when generalizing novel nouns, and a relation to vocabulary development. However, we also find that following a naming event, children who produce fewer nouns take longer to look at the objects they eventually select and make more transitions between objects before making a generalization decision. Children who produce more nouns look to the objects they eventually select more quickly following the naming event and make fewer looking transitions. We discuss these findings in the context of prior proposals regarding children's few-shot category learning, and a developmental cascade of multiple perceptual, cognitive, and word-learning processes that may operate in cases of both typical development and language delay. RESEARCH HIGHLIGHTS: Examined how novel words guide visual attention by coding frame-by-frame where children look when asked to generalize novel names. Gaze patterns differed with vocabulary size: children with smaller vocabularies attended to generalization targets more slowly and did more comparison than those with larger vocabularies. Demonstrates a relationship between vocabulary size and attention to object properties during naming. This work has implications for looking-based tests of early cognition, and our understanding of children's few-shot category learning.

Disrupting the speech motor network: Exploring hemispheric specialization for verbal and manual sequencing using a dual-task approach.

OBJECTIVE: The concept of overlapping neural networks supporting both speech production and fine motor praxis is well accepted; however, few studies have explored the lateralized behavioral characteristics of both functions when performed simultaneously. METHOD: This study probes the characteristics of the dominant hemisphere by overloading cognitive processing via a novel dual-task paradigm. In 2 experiments, participants performed sets of motor and speech tasks under single-task and dual-task conditions. The sets of tasks differed as to the extent to which they relied on sequential processing, and we hypothesized that tasks more reliant on this type of processing would suffer a greater performance decrement under dual-task conditions. A reliable measure of hemispheric language dominance was obtained via functional transcranial Doppler (fTCD) ultrasound. RESULTS: Speech production scores in the experimental set (i.e., sequential processing) were consistently impaired under dual-task conditions, a distinction that was not seen in the control set. Results of Experiment 2 confirm those of Experiment 1, whereby speech scores were most strongly impaired under dual-task conditions, especially in the experimental set. Motor performance suffered less than speech performance in dual-task conditions in both the experimental and control sets across both experiments. CONCLUSION: Data suggest that the common processing capacity for speech and fine motor praxis can be disrupted through a dual-task paradigm. This novel behavioral data supports theories of a motor-based gestural origin for language and indicates that speech production is more sensitive to the effects of increased processing requirements than are motor skills. (PsycINFO Database Record (c) 2019 APA, all rights reserved).