Tracking Multiple Statistics: Simultaneous Learning of Object Names and Categories in English and Mandarin Speakers.

Two experiments were conducted to examine adult learners' ability to extract multiple statistics in simultaneously presented visual and auditory input. Experiment 1 used a cross-situational learning paradigm to test whether English speakers were able to use co-occurrences to learn word-to-object mappings and concurrently form object categories based on the commonalities across training stimuli. Experiment 2 replicated the first experiment and further examined whether speakers of Mandarin, a language in which final syllables of object names are more predictive of category membership than English, were able to learn words and form object categories when trained with the same type of structures. The results indicate that both groups of learners successfully extracted multiple levels of co-occurrence and used them to learn words and object categories simultaneously. However, marked individual differences in performance were also found, suggesting possible interference and competition in processing the two concurrent streams of regularities.

Word comprehension and production asymmetries in children and adults.

Two studies investigated differences in the comprehension and production of words in 2-year-old children and adults. Study 1 compared children's speaking and understanding of the names of 12 novel objects presented over three weekly sessions. Study 2 tested adults' performance under similar training and testing conditions over two sessions. The findings indicated a comprehension advantage for both age groups. A fine-grained temporal analysis of individual words revealed that acquisition does not resemble a linear stage-wise progression from comprehension to production. Rather, dimensions of lexical knowledge develop at different rates, with words acquired, lost, and maintained over the course of learning. The findings support a dynamic and graded view of lexical processing and have implications for understanding what it means to know a word.

Fast mapping skills in the developing lexicon.

PURPOSE: This preliminary investigation was a longitudinal study of fast mapping skills in normally developing children, 16-18 months of age. The purpose was to examine the effects of practice on the accessibility of words in lexical memory. METHOD: Eight children were taught the names of 24 unfamiliar objects over 12 weekly training sessions. The amount of practice children had with individual words varied as a function of session. Data were compared to a control group of children-matched on productive vocabulary-who were exposed to the same experimental words at the first and last sessions only. RESULTS: The results showed that for children in the experimental group, extended practice with a novel set of high-practice words led to the rapid acquisition of a second set of low-practice words. Children in the control group did not show the same lexical advantage. CONCLUSIONS: The data suggest that learning some words primes the system to learn more words. Vocabulary development can thus be conceptualized as a continual process of fine-tuning the lexical system to enable increased accessibility to information. Implications for the treatment of children with word-finding difficulties are considered.

Priming overgeneralizations in two- and four-year-old children.

Overgeneralization occurs when a child uses the wrong word to name an object and is often observed in the early stages of word learning. We develop a method to elicit overgeneralizations in the laboratory by priming children to say the names of objects perceptually similar to known and unknown target objects. Experiment 1 examined 18 two-year-old children's labelling of familiar and unfamiliar objects, using a name that was previously produced. Experiment 2 compared the labelling of 30 two-year-olds and 39 four-year-olds when presented with completely novel objects. The findings suggest that the retrieved word is a blend of previous activation from the prior retrieval and activation engendered by the similarity of the test object to instances of the target category. We put forward a theoretical account of overgeneralization based on current models of adult language processing. The account suggests a common mechanism of activation and retrieval, which may explain not only momentary lapses in the correct selection of words, but other types of naming errors traditionally thought to reflect differences in children's underlying category representations or, perhaps, gaps in their knowledge of words.

Shape and the first hundred nouns.

This paper reports evidence from a longitudinal study in which children's attention to shape in a laboratory task of artificial noun learning was correlated with a rate shift in noun acquisitions. Eight children were tested in the laboratory at 3-week intervals beginning when they had less than 25 nouns in their productive vocabulary (M age=17 months). Children were presented with a novel word generalization task at each session. Additionally, the study examined the kinds of words the children learned early, based on parent reports, and the statistical regularities inherent in those vocabularies. The results indicate that as children learned nouns, they also learned to attend to shape in the novel word task. At the same time, children showed an acceleration in new noun production outside of the laboratory.

Is there a natural order for expressing semantic relations?

All languages rely to some extent on word order to signal relational information. Why? We address this question by exploring communicative and cognitive factors that could lead to a reliance on word order. In Study 1, adults were asked to describe scenes to another using their hands and not their mouths. The question was whether this home-made "language" would contain gesture sentences with consistent order. In addition, we asked whether reliance on order would be influenced by three communicative factors (whether the communication partner is permitted to give feedback; whether the information to be communicated is present in the context that recipient and gesturer share; whether the gesturer assumes the role of gesture receiver as well as gesture producer). We found that, not only was consistent ordering of semantic elements robust across the range of communication situations, but the same non-English order appeared in all contexts. Study 2 explored whether this non-English order is found only when a person attempts to share information with another. Adults were asked to reconstruct scenes in a non-communicative context using pictures drawn on transparencies. The adults picked up the pictures for their reconstructions in a consistent order, and that order was the same non-English order found in Study 1. Finding consistent ordering patterns in a non-communicative context suggests that word order is not driven solely by the demands of communicating information to another, but may reflect a more general property of human thought.

Object name learning provides on-the-job training for attention.

By the age of 3, children easily learn to name new objects, extending new names for unfamiliar objects by similarity in shape. Two experiments tested the proposal that experience in learning object names tunes children's attention to the properties relevant for naming--in the present case, to the property of shape--and thus facilitates the learning of more object names. In Experiment 1, a 9-week longitudinal study, 17-month-old children who repeatedly played with and heard names for members of unfamiliar object categories well organized by shapeformed the generalization that only objects with ith similar shapes have the same name. Trained children also showed a dramatic increase in acquisition of new object names outside of the laboratory during the course of the study. Experiment 2 replicated these findings and showed that they depended on children's learning both a coherent category structure and object names. Thus, children who learn specific names for specific things in categories with a common organizing property--in this case, shape--also learn to attend to just the right property--in this case, shape--for learning more object names.

Categorization and Its Developmental Relation to Early Language.

Three studies examine the developmental relation between early linguistic and cognitive achievements. Studies 1 and 2 attempt to replicate previous findings of a strong temporal link between the ages at there is a sharp rise in new nominal productions and the appearance of 2-category grouping using a longitudinal design. Studies 1 and 2 differ principally in whether the same stimuli were employed each time the children's categorization was tested or whether different stimuli were employed. Study 3 compares the categorization performance of children identified as late talkers to age-matched and language-matched controls cross-sectionally. Our findings consistently show that children's ability to classify objects in a spatial of temporal order is independent of advances in productive vocabulary growth. These results suggest that although children's developing knowledge of object categories may underlie developments in categorization and naming such developments depend on other abilities as well Studyin the past experiences of the child and the particular context in which the behavior is exhibited may be a more meaningful approach to understanding changes in categorization and ultimately its relation to language.