There is still much debate about the nature of the experiential and maturational changes that take place during childhood to bring about the sophisticated language abilities of an adult. The present study investigated text exposure as a possible source of linguistic experience that plays a role in the development of adult-like language abilities. Corpus analyses of object and passive relative clauses (Object: The book that the woman carried; Passive: The book that was carried by the woman) established the frequencies of these sentence types in child-directed speech and children's literature. We found that relative clauses of either type were more frequent in the written corpus, and that the ratio of passive to object relatives was much higher in the written corpus as well. This analysis suggests that passive relative clauses are much more frequent in a child's linguistic environment if they have high rates of text exposure. We then elicited object and passive relative clauses using a picture-description production task with eight and twelve year old children and adults. Both group and individual differences were consistent with the corpus analyses, such that older individuals and individuals with more text exposure produced more passive relative clauses. These findings suggest that the qualitatively different patterns of text versus speech may be an important source of linguistic experience for the development of adult-like language behavior.

Young children learn language from the speech they hear. Previous work suggests that the statistical diversity of words and of linguistic contexts is associated with better language outcomes. One potential source of lexical diversity is the text of picture books that caregivers read aloud to children. Many parents begin reading to their children shortly after birth, so this is potentially an important source of linguistic input for many children. We constructed a corpus of 100 children’s picture books and compared word type and token counts to a matched sample of child-directed speech. Overall, the picture books contained more unique word types than the child-directed speech. Further, individual picture books generally contained more unique word types than length-matched, child-directed conversations. The text of picture books may be an important source of vocabulary for young children, and these findings suggest a mechanism that underlies the language benefits associated with reading to children.

BackgroundThe neural substrates of olfactory working memory are unknown. We addressed the questions of whether olfactory working memory involves a verbal representation of the odor, or a sensory image of the odor, or both, and the location of the neural substrates of these processes.Methodology/Principal FindingsWe used functional magnetic resonance imaging to measure activity in the brains of subjects who were remembering either nameable or unnameable odorants. We found a double dissociation whereby remembering nameable odorants was reflected in sustained activity in prefrontal language areas, and remembering unnameable odorants was reflected in sustained activity in primary olfactory cortex.Conclusions/SignificanceThese findings suggest a novel dedicated mechanism in primary olfactory cortex, where odor information is maintained in temporary storage to subserve ongoing tasks.

The words in children's language learning environments are strongly predictive of cognitive development and school achievement. But how do we measure language environments and do so at the scale of the many words that children hear day in, day out? The quantity and quality of words in a child's input are typically measured in terms of total amount of talk and the lexical diversity in that talk. There are disagreements in the literature whether amount or diversity is the more critical measure of the input. Here we analyze the properties of a large corpus (6.5 million words) of speech to children and simulate learning environments that differ in amount of talk per unit time, lexical diversity, and the contexts of talk. The central conclusion is that what researchers need to theoretically understand, measure, and change is not the total amount of words, or the diversity of words, but the function that relates total words to the diversity of words, and how that function changes across different contexts of talk.

The role of visual salience on utterance form was investigated in a picture description study. Participants heard spoken questions about animate or inanimate entities in a picture and produced a relative clause in response. Visual properties of the scenes affected production choices such that less salient inanimate entities tended to yield longer initiation latencies and to be described with passive relative clauses more than visually salient inanimates. We suggest that the participants’ question-answering task can change as a function of visual salience of entities in the picture. Less salient entities require a longer visual search of the scene, which causes the speaker to notice or attend more to the non-target competitors in the picture. As a result, it becomes more important in answering the question for the speaker to contrast the target item with a salient competitor. This effect is different from other effects of visual salience, which tend to find that more salient entities take more prominent grammatical roles in the sentence. We interpret this discrepancy as evidence that visual salience does not have a single effect on sentence production, but rather its effect is modulated by task and linguistic context.