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L Fenson

Publications and source records attributed to L Fenson.

8 recordsLinked to original sources
PubMed1994

Developmental and stylistic variation in the composition of early vocabulary.

Results are reported for stylistic and developmental aspects of vocabulary composition for 1,803 children and families who participated in the tri-city norming of a new parental report instrument, the MacArthur Communicative Development Inventories. We replicate previous studies with small samples showing extensive variation in use of common nouns between age 0; 8 and 1;4 (i.e. 'referential style'), and in the proportion of vocabulary made up of closed-class words between 1;4 and 2;6 (i.e. 'analytic' vs. 'holistic' style). However, both style dimensions are confounded with developmental changes in the composition of the lexicon, including three 'waves' of reorganization: (I) an initial increase in percentage of common nouns from 0 to 100 words, followed by a proportional decrease; (2) a slow linear increase in verbs and other predicates, with the greatest gains taking place between 100 and 400 words; (3) no proportional development at all in the use of closed-class vocabulary between 0 and 400 words, followed by a sharp increase from 400 to 680 words. When developmental changes in noun use are controlled, referential-style measures do not show the association with developmental precocity reported in previous studies, although these scores are related to maternal education. By contrast, when developmental changes in grammatical function word use are controlled, high closed-class scores are associated with a slower rate of development. We suggest that younger children may have less perceptual acuity and/or shorter memory spans than older children with the same vocabulary size. As a result, the younger children may ignore unstressed function words until a later point in development while the older children tend to reproduce perceptual details that they do not yet understand. Longitudinal data show that early use of function words (under 400 words) is not related to grammatical levels after the 400-word point, confirming our 'stylistic' interpretation of early closed-class usage. We close with recommendations for the unconfounding of stylistic and developmental variance in research on individual differences in language development, and provide look-up tables that will permit other investigators to pull these aspects apart.

Child Language↗
PubMed1994

Variability in early communicative development.

Data from parent reports on 1,803 children--derived from a normative study of the MacArthur Communicative Development Inventories (CDIs)--are used to describe the typical course and the extent of variability in major features of communicative development between 8 and 30 months of age. The two instruments, one designed for 8-16-month-old infants, the other for 16-30-month-old toddlers, are both reliable and valid, confirming the value of parent reports that are based on contemporary behavior and a recognition format. Growth trends are described for children scoring at the 10th-, 25th-, 50th-, 75th-, and 90th-percentile levels on receptive and expressive vocabulary, actions and gestures, and a number of aspects of morphology and syntax. Extensive variability exists in the rate of lexical, gestural, and grammatical development. The wide variability across children in the time of onset and course of acquisition of these skills challenges the meaningfulness of the concept of the modal child. At the same time, moderate to high intercorrelations are found among the different skills both concurrently and predictively (across a 6-month period). Sex differences consistently favor females; however, these are very small, typically accounting for 1%-2% of the variance. The effects of SES and birth order are even smaller within this age range. The inventories offer objective criteria for defining typicality and exceptionality, and their cost effectiveness facilitates the aggregation of large data sets needed to address many issues of contemporary theoretical interest. The present data also offer unusually detailed information on the course of development of individual lexical, gestural, and grammatical items and features. Adaptations of the CDIs to other languages have opened new possibilities for cross-linguistic explorations of sequence, rate, and variability of communicative development.

Birth Order↗
PubMed1989

Children's knowledge of thematic and taxonomic relations at two years of age.

An interesting conflict exists in the developmental literature concerning the strength of thematic versus taxonomic associations. "Dog-doghouse" is a thematic match, while "dog-horse" is a taxonomic match. This study compared the ability of children to identify both types of associations at 2 points during the third year of life: 26 months (N = 15) and 34 months (N = 24). A reinforced match-to-sample technique was used in which half of the matches were thematic and the other half were taxonomic. Both age groups were able to identify thematic matches, although children near 3 years of age were able to recognize a wider range of thematic associations than children near 2 years of age. The 26-month-olds were unable to identify taxonomic matches that had no perceptual basis, but the 34-month-olds were successful at this task; the 34-month-olds appeared to have a more general understanding of categories that was less tied to perceptual features.

Association↗
PubMed1988

Role of perceptual and conceptual similarity in category matching at age two years.

Perceptual and categorical similarity were varied independently in a concept-matching task administered to 26-month-old children (N = 25). 44 test sets were assembled. Each set included a 3-dimensional standard and an array of 4 pictures, one of which was a member of the same basic or superordinate category as the standard. On each trial, placing the standard on the matching picture resulted in activation of 1 of 12 mechanical displays. The test sets varied in the perceptual and categorical resemblance of the standard to the match and to the nonmatches, as determined by adults' ratings. Perceptual similarity proved to be the primary determinant of difficulty level. When perceptual resemblance of the standard and the match were equated, superordinate and basic matches were equally difficult. When perceptual resemblance was minimal, most children were unable to recognize matches at either the basic or superordinate level.

Association↗
PubMed1981

Effects of modeling action sequences on the play of twelve-, fifteen, and nineteen-month-old children.

3 studies examined the relation between the spontaneous occurrence in play of simple 2-part action sequences and the frequency of these sequences and their components following modeling at 12, 15, and 19 months of age. Play following modeling was typically more advanced than play preceding modeling. Moreover, imitation was tied to developmental level. Children at 19 months of age were generally able to imitate complete sequences, though only a few 19-month-olds performed such actions spontaneously. Children at 15 months of age typically did not imitate complete sequences except under simplified experimental conditions, and, even then, their ability to perform sequences was attenuated relative to the 19-month-olds. However, 15-month-olds did imitate many single components of the 2-part combinations and, to a lesser extent, exhibited these components spontaneously. A smaller number of 12-month-olds imitated components, which were rarely displayed spontaneously at this age. The results suggested that a general combinatorial capacity in play emerges between 15 and 19 months of age.

Child Development↗
PubMedDate not supplied

Measuring variability in early child language: don't shoot the messenger.

Feldman et al. criticize the MacArthur Communicative Development Inventories (CDIs) as having too much variability, too little stability, and insufficient ability to predict early language delay. We present data showing that these characteristics of the CDI are authentic reflections of individual differences in early language development rather than measurement deficiencies. We also respond to their critical assertions concerning sociodemographic influences on the CDI scores.

Child Development↗