Flexible fast-mapping: Deaf children dynamically allocate visual attention to learn novel words in American Sign Language.

Word learning in young children requires coordinated attention between language input and the referent object. Current accounts of word learning are based on spoken language, where the association between language and objects occurs through simultaneous and multimodal perception. In contrast, deaf children acquiring American Sign Language (ASL) perceive both linguistic and non-linguistic information through the visual mode. In order to coordinate attention to language input and its referents, deaf children must allocate visual attention optimally between objects and signs. We conducted two eye-tracking experiments to investigate how young deaf children allocate attention and process referential cues in order to fast-map novel signs to novel objects. Participants were deaf children learning ASL between the ages of 17 and 71 months. In Experiment 1, participants (n = 30) were presented with a novel object and a novel sign, along with a referential cue that occurred either before or after the sign label. In Experiment 2, a new group of participants (n = 32) were presented with two novel objects and a novel sign, so that the referential cue was critical for identifying the target object. Across both experiments, participants showed evidence for fast-mapping the signs regardless of the timing of the referential cue. Individual differences in children's allocation of attention during exposure were correlated with their ability to fast-map the novel signs at test. This study provides first evidence for fast-mapping in sign language, and contributes to theoretical accounts of how word learning develops when all input occurs in the visual modality.

Mapping Word to World in ASL: Evidence from a Human Simulation Paradigm.

Across languages, children map words to meaning with great efficiency, despite a seemingly unconstrained space of potential mappings. The literature on how children do this is primarily limited to spoken language. This leaves a gap in our understanding of sign language acquisition, because several of the hypothesized mechanisms that children use are visual (e.g., visual attention to the referent), and sign languages are perceived in the visual modality. Here, we used the Human Simulation Paradigm in American Sign Language (ASL) to determine potential cues to word learning. Sign-naïve adult participants viewed video clips of parent-child interactions in ASL, and at a designated point, had to guess what ASL sign the parent produced. Across two studies, we demonstrate that referential clarity in ASL interactions is characterized by access to information about word class and referent presence (for verbs), similarly to spoken language. Unlike spoken language, iconicity is a cue to word meaning in ASL, although this is not always a fruitful cue. We also present evidence that verbs are highlighted well in the input, relative to spoken English. The results shed light on both similarities and differences in the information that learners may have access to in acquiring signed versus spoken languages.

The role of redundant verbal labels in 8- and 10-month-olds' working memory.

Verbal labels have been shown to help preverbal infants' performance on various cognitive tasks, such as categorization. Redundant labels also aid adults' visual working memory (WM), but it is not known if this linguistic benefit extends to preverbal infants' WM. In two eye-tracking studies, we tested whether 8- and 10-month-old infants' WM performance would improve with the presence of redundant labels in a Delayed Match Retrieval (DMR) paradigm that tested infants' WM for object-location bindings. Findings demonstrated that infants at both ages were unable to remember two object-location bindings when co-presented with labels at encoding. Moreover, infants who encoded the object-location bindings with labels were not significantly better than those who did so in silence. These findings are discussed in the context of label advantages in cognition and auditory dominance.

Toddlers' word learning through overhearing: Others' attention matters.

In laboratory settings children are able to learn new words from overheard interactions, yet in naturalistic contexts this is often not the case. We investigated the degree to which joint attention within the overheard interaction facilitates overheard learning. In the study, 20 2-year-olds were tested on novel words they had been exposed to in two different overhearing contexts: one in which both interlocutors were attending to the interaction and one in which one interlocutor was not attending. Participants learned the new words only in the former condition, indicating that they did not learn when joint attention was absent. This finding demonstrates that not all overheard interactions are equally good for word learning; attentive interlocutors are crucial when learning words through overhearing.

Toddlers with Autism Spectrum Disorder Can Use Language to Update Their Expectations About the World.

This study examined if two-year-olds with ASD can update mental representations on the basis of verbal input. In an eye-tracking study, toddlers with ASD and typically-developing nonverbal age-matched controls were exposed to visual or verbal information about a change in a recently encoded scene, followed by an outcome that was either congruent or incongruent with that information. Findings revealed that both groups looked longer at incongruent outcomes, regardless of information modality, and despite the fact that toddlers with ASD had significantly lower measured verbal abilities than TD toddlers. This demonstrates that, although there is heterogeneity on the individual level, young toddlers with ASD can succeed in updating their mental representations on the basis of verbal input in a low-demand task.

Off to a Good Start: The Early Development of the Neural Substrates Underlying Visual Working Memory.

Current neuroscientific models describe the functional neural architecture of visual working memory (VWM) as an interaction of the frontal-parietal control network and more posterior areas in the ventral visual stream (Jonides et al., 2008; D'Esposito and Postle, 2015; Eriksson et al., 2015). These models are primarily based on adult neuroimaging studies. However, VWM undergoes significant development in infancy and early childhood, and the goal of this mini-review is to examine how recent findings from neuroscientific studies of early VWM development can be reconciled with this model. We surveyed 29 recent empirical reports that present neuroimaging findings in infants, toddlers, and preschoolers (using EEG, fNIRS, rs-fMRI) and neonatal lesion studies in non-human primates. We conclude that (1) both the frontal-parietal control network and the posterior cortical storage areas are active from early infancy; (2) this system undergoes focalization and some reorganization during early development; (3) and the MTL plays a significant role in this process as well. Motivated by both theoretical and methodological considerations, we offer some recommendations for future directions for the field.

Sixteen-month-olds can use language to update their expectations about the visual world.

The capacity to use language to form new representations and to revise existing knowledge is a crucial aspect of human cognition. Here we examined whether infants can use language to adjust their representation of a recently encoded scene. Using an eye-tracking paradigm, we asked whether 16-month-old infants (N=26; mean age=16;0 [months;days], range=14;15-17;15) can use language about an occluded event to inform their expectation about what the world will look like when the occluder is removed. We compared looking time to outcome scenes that matched the language input with looking time to those that did not. Infants looked significantly longer at the event outcome when the outcome did not match the language input, suggesting that they generated an expectation of the outcome based on that input alone. This effect was unrelated to infants' vocabulary size. Thus, using language to adjust expectations about the visual world is present at an early developmental stage even when language skills are rudimentary.

Detail and gestalt focus in individuals with optimal outcomes from autism spectrum disorders.

Individuals with high-functioning autism (HFA) have a cognitive style that privileges local over global or gestalt details. While not a core symptom of autism, individuals with HFA seem to reliably show this bias. Our lab has been studying a sample of children who have overcome their early ASD diagnoses, showing "optimal outcomes" (OO). This study characterizes performance by OO, HFA, and typically developing (TD) adolescents as they describe paintings under cognitive load. Analyses of detail focus in painting descriptions indicated that the HFA group displayed significantly more local focus than both OO and TD groups, while the OO and TD groups did not differ. We discuss implications for the centrality of detail focus to the autism diagnosis.