Laura L. Namy

Comparison in the Development of Categories

Recent research on children’s word learning has led to a paradox. Although word learning appears to be a deep source of insight into conceptual knowledge for children, preschoolers often categorize objects on the basis of shallow perceptual features such as shape. The current studies seek to resolve this discrepancy. We suggest that comparing multiple instances of a category enables children to extract deeper relational commonalities among category members. We examine 4-year-olds’ categorization behaviors when asked to select a match for a target object (e.g., an apple) between a perceptually similar, out-of-kind object (e.g., a balloon) and a perceptually different category match (e.g., a banana). Children who learn a novel word as a label for multiple instances of the category are more likely to select the category match over the perceptual match. Children who learn a label for only one instance are equally likely to select either alternative. This effect is present even when individual target instances are more perceptually similar to the perceptual choice than to the category choice. We conclude that structural alignment processes may be important in the development of category understanding.

Challenging the Notion of a Thematic Preference in Young Children.

Many researchers have argued that early cognitive development is characterized by a conceptual preference for thematic over taxonomic relations. However, more recent research indicates that infants and toddlers may not favor thematic relations. To resolve this discrepancy, the conceptual preferences of children ranging from 2 to 4 years of age were examined, using a forced-choice task including a target (e.g., a carrot), a thematic alternative (e.g., a rabbit), and a taxonomic alternative (e.g., a tomato). The effects of age, experimenters instructions, hierarchical level (basic vs. superordinate), and stimulus medium (pictures vs. objects) were examined systematically. Children revealed no pervasive preference for either thematic or taxonomic relations. This challenges the notion of a developmental shift in conceptual preferences and suggests a more continuous trajectory in early conceptual development.

Gender Differences in Vocal Accommodation:: The Role of Perception

This study examined how perceptual sensitivity contributes to gender differences in vocal accommodation. Male and female shadowers repeated isolated words presented over headphones by male and female speakers, and male and female listeners evaluated whether accommodation occurred. Female shadowers accommodated more than males, and more to males than to female speakers, although some speakers elicited greater accommodation than others. Gender differences in accommodation emerged even when immediate social motives were minimized, suggesting that accommodation may be due, in part, to differences in perceptual sensitivity to vocal characteristics.

Analogical Processes in Language Learning

The acquisition of language has long stood as a challenge to general learning accounts, leading many theorists to propose domain-specific knowledge and processes to explain language acquisition. Here we review evidence that analogical comparison is instrumental in language learning, suggesting a larger role for general learning processes in the acquisition of language.

The semantics of prosody: acoustic and perceptual evidence of prosodic correlates to word meaning.

This investigation examined whether speakers produce reliable prosodic correlates to meaning across semantic domains and whether listeners use these cues to derive word meaning from novel words. Speakers were asked to produce phrases in infant-directed speech in which novel words were used to convey one of two meanings from a set of antonym pairs (e.g., big/small). Acoustic analyses revealed that some acoustic features were correlated with overall valence of the meaning. However, each word meaning also displayed a unique acoustic signature, and semantically related meanings elicited similar acoustic profiles. In two perceptual tests, listeners either attempted to identify the novel words with a matching meaning dimension (picture pair) or with mismatched meaning dimensions. Listeners inferred the meaning of the novel words significantly more often when prosody matched the word meaning choices than when prosody mismatched. These findings suggest that speech contains reliable prosodic markers to word meaning and that listeners use these prosodic cues to differentiate meanings. That prosody is semantic suggests a reconceptualization of traditional distinctions between linguistic and nonlinguistic properties of spoken language.

Recognition of iconicity doesn't come for free

Iconicity--resemblance between a symbol and its referent--has long been presumed to facilitate symbolic insight and symbol use in infancy. These two experiments test childrens ability to recognize iconic gestures at ages 14 through 26 months. The results indicate a clear ability to recognize how a gesture resembles its referent by 26 months, but little evidence of recognition of iconicity at the onset of symbolic development. These findings imply that iconicity is not available as an aid at the onset of symbolic development but rather that the ability to apprehend the relation between a symbol and its referent develops over the course of the second year.

Developmental Changes in Neural Activity to Familiar Words and Gestures.

Infants younger than 20 months of age interpret both words and symbolic gestures as object names. Later in development words and gestures take on divergent communicative functions. Here, we examined patterns of brain activity to words and gestures in typically developing infants at 18 and 26 months of age. Event-related potentials (ERPs) were recorded during a match/mismatch task. At 18 months, an N400 mismatch effect was observed for pictures preceded by both words and gestures. At 26 months the N400 effect was limited to words. The results provide the first neurobiological evidence showing developmental changes in semantic processing of gestures.

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 childrens 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 childrens ability to classify objects in a spatial of temporal order is independent of advances in productive vocabulary growth. These results suggest that although childrens 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.

Young Children's Discovery of Spatial Classification.

Abstract Around the age of 18 months, children begin to classify objects spatially by kind, placing objects of the same kind close together in space and placing unlike objects apart. This behavior may be symbolic in the sense that children use spatial proximity to represent similarity. We examined the possibility that spatial classification is discovered during play—that the external products of play lead children to use space to represent similarity. Experiment 1 was a longitudinal study of four childrens classification behaviors, observed from the age of 16 to 21 months. Results suggest that play with one kind of object to the exclusion of another kind leads to the discovery of spatial classification. Experiment 2 examined how childrens tendencies to interact with one category might promote spatial classification of multiple categories. Twenty-four 18-month-old children who did not yet spatially classify objects by kind participated. Children who were given the experience of playing with two kinds of objects in a context that promoted interaction with only one kind were more likely to demonstrate spontaneous spatial classification of multiple kinds in a subsequent test period. Children who played equally with both kinds did not show heightened spontaneous classification. The results further suggest that comparison of different kinds during play is critical to the spontaneous occurrence of spatial classification.

Cross-linguistic sound symbolism and crossmodal correspondence: Evidence from fMRI and DTI.

Non-arbitrary correspondences between spoken words and categories of meanings exist in natural language, with mounting evidence that listeners are sensitive to this sound symbolic information. Native English speakers were asked to choose the meaning of spoken foreign words from one of four corresponding antonym pairs selected from a previously developed multi-language stimulus set containing both sound symbolic and non-symbolic stimuli. In behavioral (n=9) and fMRI (n=15) experiments, participants showed reliable sensitivity to the sound symbolic properties of the stimulus set, selecting the consistent meaning for the sound symbolic words at above chances rates. There was increased activation for sound symbolic relative to non-symbolic words in left superior parietal cortex, and a cluster in left superior longitudinal fasciculus showed a positive correlation between fractional anisotropy (FA) and an individuals sensitivity to sound symbolism. These findings support the idea that crossmodal correspondences underlie sound symbolism in spoken language.