The Ontogeny of Lexical Networks Toddlers Encode the Relationships Among Referents When Learning Novel Words

Although the semantic relationships among words have long been acknowledged as a crucial component of adult lexical knowledge, the ontogeny of lexical networks remains largely unstudied. To determine whether learners encode relationships among novel words, we trained 2-year-olds on four novel words that referred to four novel objects, which were grouped into two visually similar pairs. Participants then listened to repetitions of word pairs (in the absence of visual referents) that referred to objects that were either similar or dissimilar to each other. Toddlers listened significantly longer to word pairs referring to similar objects, which suggests that their representations of the novel words included knowledge about the similarity of the referents. A second experiment confirmed that toddlers can learn all four distinct words from the training regime, which suggests that the results from Experiment 1 reflected the successful encoding of referents. Together, these results show that toddlers encode the similarities among referents from their earliest exposures to new words

Toddlers Encode Similarities Among Novel Words from Meaningful Sentences

Toddlers can learn about the meanings of individual words from the structure and semantics of the sentences in which they are embedded. However, it remains unknown whether toddlers encode similarities among novel words based on their positions within sentences. In three experiments, two-year-olds listened to novel words embedded in familiar sentence frames. Some novel words consistently occurred in the subject position across sentences, and others in the object position across sentences. An auditory semantic task was used to test whether toddlers encoded similarities based on sentential position, for (a) pairs of novel words that occurred within the same sentence, and (b) pairs of novel words that occurred in the same position across sentences. The results suggest that while toddlers readily encoded similarity based on within-sentence occurrences, only toddlers with more advanced grammatical knowledge encoded the positional similarities of novel words across sentences. Moreover, the encoding of these cross-sentential relationships only occurred if the exposure sentences included a familiar verb. These studies suggest that the types of lexical relationships that toddlers learn depend on the child’s current level of language development, as well as the structure and meaning of the sentences surrounding the novel words

Idiomatic syntactic constructions and language learning.

Abstract This article explores the influence of idiomatic syntactic constructions (i.e., constructions whose phrase structure rules violate the rules that underlie the construction of other kinds of sentences in the language) on the acquisition of phrase structure. In Experiment 1, participants were trained on an artificial language generated from hierarchical phrase structure rules. Some participants were given exposure to an idiomatic construction (IC) during training, whereas others were not. Under some circumstances, the presence of an idiomatic construction in the input aided learners in acquiring the phrase structure of the language. Experiment 2 provides a replication of the first experiment and extends the findings by showing that idiomatic constructions that strongly violate the predictive dependencies that define the phrase structure of the language do not aid learners in acquiring the structure of the language. Together, our data suggest that (a) idiomatic constructions aid learners in acquiring the phrase structure of a language by highlighting relevant structural elements in the language, and (b) such constructions are useful cues to learning to the extent that learners can keep their knowledge of the idiomatic construction separate from their knowledge of the rest of the language

Toddlers Activate Lexical Semantic Knowledge in the Absence of Visual Referents: Evidence from Auditory Priming

Language learners rapidly acquire extensive semantic knowledge, but the development of this knowledge is difficult to study, in part because it is difficult to assess young children\u27s lexical semantic representations. In our studies, we solved this problem by investigating lexical semantic knowledge in 24-month-olds using the Head-turn Preference Procedure. In Experiment 1, looking times to a repeating spoken word stimulus (e.g., kitty-kitty-kitty) were shorter for trials preceded by a semantically related word (e.g., dog-dog-dog) than trials preceded by an unrelated word (e.g., juice-juice-juice). Experiment 2 yielded similar results using a method in which pairs of words were presented on the same trial. The studies provide evidence that young children activate of lexical semantic knowledge, and critically, that they do so in the absence of visual referents or sentence contexts. Auditory lexical priming is a promising technique for studying the development and structure of semantic knowledge in young children

Non-Linguistic Constraints on the Acquisition of Phrase Structure

To what extent is linguistic structure learnable from statistical information in the input? One set of cues which might assist in the discovery of hierarchical phrase structure given serially presented input are the dependencies, or predictive relationships, present within phrases. In order to determine whether adult learners can use this statistical information, subjects were exposed to artificial languages which either contained or violated the kinds of dependencies which characterize natural languages. The results suggest that adults possess learning mechanisms which detect and utilize statistical cues to phrase and hierarchical structure. A second experiment contrasted the acquisition of these linguistic systems with the same grammars implemented as non-linguistic input (sequences of non-linguistic sounds or shapes). These findings suggest that constraints on the mechanisms which highlight the statistical cues which are most characteristic of human languages are not specifically tailored for language learning

Statistical learning as a window into developmental disabilities

Abstract Until recently, most behavioral studies of children with intellectual and developmental disabilities (IDD) have used standardized assessments as a means to probe etiology and to characterize phenotypes. Over the past decade, however, tasks originally developed to investigate learning processes in typical development have been brought to bear on developmental processes in children with IDD. This brief review will focus on one learning process in particular—statistical learning—and will provide an overview of what has been learned thus far from studies using statistical learning tasks with different groups of children with IDD conditions. While a full picture is not yet available, results to date suggest that studies of learning are both feasible and informative about learning processes that may differ across diagnostic groups, particularly as they relate to language acquisition. More generally, studies focused on learning processes may be highly informative about different developmental trajectories both across groups and within groups of children

Roses Are Red, Socks Are Blue: Switching Dimensions Disrupts Young Children's Language Comprehension.

Language is used to identify objects in many different ways. An apple can be identified using its name, color, and other attributes. Skilled language comprehension requires listeners to flexibly shift between different dimensions. We asked whether this shifting would be difficult for 3-year-olds, who have relatively immature executive function skills and struggle to switch between dimensions in card sorting tasks. In the current experiment, children first heard a series of sentences identifying objects using a single dimension (either names or colors). In the second half of the experiment, the labeling dimension was switched. Children were significantly less accurate in fixating the correct object following the dimensional switch. This disruption, however, was temporary; recognition accuracy recovered with increased exposure to the new labeling dimension. These findings provide the first evidence that children's difficulty in shifting between dimensions impacts their ability to comprehend speech. This limitation may affect children's ability to form rich, multi-dimensional representations when learning new words

Expectancy Learning from Probabilistic Input by Infants

Across the first few years of life, infants readily extract many kinds of regularities from their environment, and this ability is thought to be central to development in a number of domains. Numerous studies have documented infants’ ability to recognize deterministic sequential patterns. However, little is known about the processes infants use to build and update representations of structure in time, and how infants represent patterns that are not completely predictable. The present study investigated how infants’ expectations fora simple structure develope over time, and how infants update their representations with new information. We measured 12-month-old infants’ anticipatory eye movements to targets that appeared in one of two possible locations. During the initial phase of the experiment, infants either saw targets that appeared consistently in the same location (Deterministic condition) or probabilistically in either location, with one side more frequent than the other (Probabilistic condition). After this initial divergent experience, both groups saw the same sequence of trials for the rest of the experiment. The results show that infants readily learn from both deterministic and probabilistic input, with infants in both conditions reliably predicting the most likely target location by the end of the experiment. Local context had a large influence on behavior: infants adjusted their predictions to reflect changes in the target location on the previous trial. This flexibility was particularly evident in infants with more variable prior experience (the Probabilistic condition). The results provide some of the first data showing how infants learn in real time