Search PubMed⌕ Search

Biomedical subjects

C B Mervis

Publications and source records attributed to C B Mervis.

At least 19 recordsLinked to original sources
PubMed1996

LIM-kinase1 hemizygosity implicated in impaired visuospatial constructive cognition.

To identify genes important for human cognitive development, we studied Williams syndrome (WS), a developmental disorder that includes poor visuospatial constructive cognition. Here we describe two families with a partial WS phenotype; affected members have the specific WS cognitive profile and vascular disease, but lack other WS features. Submicroscopic chromosome 7q11.23 deletions cosegregate with this phenotype in both families. DNA sequence analyses of the region affected by the smallest deletion (83.6 kb) revealed two genes, elastin (ELN) and LIM-kinase1 (LIMK1). The latter encodes a novel protein kinase with LIM domains and is strongly expressed in the brain. Because ELN mutations cause vascular disease but not cognitive abnormalities, these data implicate LIMK1 hemizygosity in imparied visuospatial constructive cognition.

Base Sequence↗
PubMed1996

Mapping the meanings of novel visual symbols by youth with moderate or severe mental retardation.

The word-learning ability of 12 school-age subjects with moderate or severe mental retardation was assessed. Subjects had little or no functional speech and used the System for Augmenting Language with visual-graphic symbols for communication. Their ability to fast map novel symbols revealed whether they possessed the novel name-nameless category (N3C) lexical operating principle. On first exposure, 7 subjects were able to map symbol meanings for novel objects. Follow-up assessments indicated that mappers retained comprehension of some of the novel words for up to delays of 15 days and generalized their knowledge to production. Ability to fast map reliably was related to symbol achievement status. Implications for understanding vocabulary acquisition by youth with mental retardation were discussed.

Adolescent↗
PubMed1995

Early lexical acquisition and the vocabulary spurt: a response to Goldfield & Reznick.

Vocabulary development of three children (aged 1;6-1;8 at the start of the study) who had not begun to evidence a vocabulary spurt even though their productive vocabularies already included well over 50 words was followed to determine if these children eventually would have a vocabulary spurt. All three children evidenced a spurt, beginning at a mean productive vocabulary size of 112 words. The vocabulary spurt occurred at about the same time as the children first demonstrated the ability to sort objects exhaustively and to fast map new object names. Results are discussed in the context of Goldfield & Reznick's (1990; Reznick & Goldfield, 1992) argument that a substantial proportion of children never evidence a vocabulary spurt.

Child Language↗
PubMed1995

Acquisition of the novel name-nameless category (N3C) principle by young children who have Down syndrome.

Acquisition of the novel name-nameless category (N3C) principle by 22 children with Down syndrome between the ages of 2.42 and 3.33 years was examined to investigate the generalizability of a new approach to early lexical development: the developmental lexical principles framework. Results indicated that, as predicted, the N3C principle (operationally defined as the ability to fast map a new word to a [basic level] category), is not available at the start of lexical acquisition. The predicted link between ability to use the N3C principle and ability to perform exhaustive categorization of objects was supported. Children who used the principle had significantly larger productive vocabularies than did those who did not and, according to maternal report, had begun to acquire new words rapidly.

Child Language↗
PubMed1994

Early object labels: the case for a developmental lexical principles framework.

Universally, object names make up the largest proportion of any word type found in children's early lexicons. Here we present and critically evaluate a set of six lexical principles (some previously proposed and some new) for making object label learning a manageable task. Overall, the principles have the effect of reducing the amount of information that language-learning children must consider for what a new word might mean. These principles are constructed by children in a two-tiered developmental sequence, as a function of their sensitivity to linguistic input, contextual information, and social-interactional cues. Thus, the process of lexical acquisition changes as a result of the particular principles a given child has at his or her disposal. For children who have only the principles of the first tier (reference, extendibility, and object scope), word learning has a deliberate and laborious look. The principles of the second tier (categorical scope, novel name-nameless category' or N3C, and conventionality) enable the child to acquire many new labels rapidly. The present unified account is argued to have a number of advantages over treating such principles separately and non-developmentally. Further, the explicit recognition that the acquisition and operation of these principles is influenced by the child's interpretation of both linguistic and non-linguistic input is seen as an advance.

Child Language↗
PubMed1994

Acquisition of the novel name--nameless category (N3C) principle.

Toddlers' acquisition of the Novel Name-Nameless Category (N3C) principle was examined to investigate the developmental lexical principles framework and the applicability of the specificity hypothesis to relations involving lexical principles. In Study 1, we assessed the ability of 32 children between the ages of 16 and 20 months to use the N3C principle (operationally defined as the ability to fast map). As predicted, only some of the children could fast map. This finding provided evidence for a crucial tenet of the developmental lexical principles framework: Some lexical principles are not available at the start of language acquisition. Children who had acquired the N3C principle also had significantly larger vocabularies and were significantly more likely to demonstrate 2-category exhaustive sorting abilities than children who had not acquired the principle. The 2 groups of children did not differ in either age or object permanence abilities. The 16 children who could not fast map were followed longitudinally until they attained a vocabulary spurt; at that time, their ability to fast map was retested (Study 2). Results provided a longitudinal replication of the findings of Study 1. Implications of these findings for both the developmental lexical principles framework and the specificity hypothesis are discussed.

Child Development↗
PubMed1994

Two-year-olds readily learn multiple labels for the same basic-level category.

2 basic frameworks for lexical principles have been proposed (Golinkoff, Mervis, & Hirsh-Pasek; Markman). In many types of situations, these frameworks make the same predictions regarding 2-year-olds' interpretation of novel terms. However, the predictions diverge in some cases. 3 experiments were conducted to address 1 such situation: the case in which the child hears a novel term but already knows a label for each of the objects present. Results of all 3 studies converged on the same outcome: The new term was most likely to be treated as a second basic-level name for the category to which the object belonged. Analyses of individual patterns of responding revealed that, of the 58 subjects, 50 made more basic-level responses than part responses, 1 made equal numbers of basic-level and part responses, and 7 made more part responses than basic-level responses. Implications of these findings for models of early lexical development are discussed.

Age Factors↗
PubMed1990

Mothers' use of substantive deixis and nouns with their children with Down syndrome: some discrepant findings.

Mothers of children with Down syndrome were compared to mothers of nonretarded children with regard to the proportions of substantive deixis and of nouns (as opposed to pronouns) they used from the time when their children were prelinguistic until after they had started to talk. Five comparisons were made. At the time of the first comparison, the children with Down syndrome ranged in age from 17 to 21 months. The nonretarded children were between 9 and 10 months old. None of the children could comprehend or produce language referentially. At the time of the fifth comparison, the children with Down syndrome were between 30 and 38 months old and the nonretarded children, between 16 and 20 months old. No significant differences were observed between the two groups of mothers for either proportion of substantive deixis or proportion of nouns. These results contrast with the results we obtained in a previous investigation (Cardoso-Martins & Mervis, 1985). Possible reasons for these discrepant findings were discussed.

Down Syndrome↗
PubMed1989

Patterns of object-name extension in production.

The evolution of young children's categories, as measured by category name production, was studied. The focus was on categories whose names initially were overextended. Four children (initially aged 1.1 to 1.3) were visited at home twice a week over a four- to six-month period, until they were approximately 1.7. The play sessions included elicitations of the names of specially chosen objects. Results indicated that, as predicted, four sequences of category evolution were found, formed by the intersection of two factors: overlap vs. mutual exclusivity and first re-assignment separate vs. first re-assignment joint. As expected, most sequences involved initial overlap, and the choice of first reassignment option varied as a function of the relationship (hierarchical or non-hierarchical) between the initial child-basic category and the new category.

Concept Formation↗
PubMed1986

Effects of receptive and expressive training of category labels on generalized learning by severely mentally retarded children.

The effects of receptive vs. expressive training of category labels on the acquisition of generalized referential labels by prelinguistic severely mentally retarded children were investigated. A crossover design was used, in which each subject received the two conditions successively; order of presentation of conditions was counterbalanced across subjects. The data indicated that receptive training resulted in more accurate generalization to novel category members than did expressive training. Further, generalization was above chance levels following receptive training but not following expressive training. The importance of these results for designing and evaluating generalized labeling instruction for severely retarded children was considered.

Adolescent↗
PubMed1985

Early vocabulary acquisition by children with Down syndrome.

Early acquisition of object names by 6 children with Down syndrome relative to the acquisition pattern of 6 nonretarded children was investigated. Each child was followed for 14 to 21 months. At the start of the study the children with Down syndrome were 17 to 19 months old. The nonretarded children were 9 months old. Results indicated that the children with Down syndrome were at the same level of cognitive development as the nonretarded children at the onset of both comprehension and production of object names. Soon after language acquisition began, however, the language development of the Down syndrome group began to lag behind their cognitive development: Level of vocabulary development was lower than would have been expected based on level of cognitive development.

Cognition↗
PubMed1985

Maternal speech to prelinguistic children with Down syndrome.

The linguistic environment of prelinguistic children with Down syndrome who were cognitively ready to talk was investigated. Maternal speech to these children was compared to maternal speech to three groups of nonhandicapped children: one matched for level of linguistic development; one matched for MA, and one matched for CA. Mother and child participated in a 45-minute free-play session, using a specially chosen set of toys. As predicted, the language of the mothers of the children with Down syndrome differed significantly from that of the mothers of each of the groups of nonhandicapped children with regard to the functional language features studied.

Child, Preschool↗
PubMed1984

Interactive basis of severely handicapped and normal children's acquisition of referential language.

The purpose of this study was to compare the interactions of prelinguistic severely handicapped children and their caregivers to the interactions of prelinguistic normal children and their mothers. The children were matched for level of sensorimotor development. Comparisons were made with regard to the children's use of gestures, patterns of play, and natural opportunities for developmentally appropriate communicative stimulation. These comparisons were based on observations of each child and his caregiver during a 30-min period of naturalistic play. Overall, no significant differences were found between the children's use of prelinguistic gestures or in their patterns of play. Significant differences were found, however, between the communicative environments of the two groups of children. The severely handicapped children experienced significantly fewer opportunities to hear labels for the objects of their attention or to observe functional object demonstrations. Both the theoretical implications and the practical applications of these findings were considered.

Adolescent↗
PubMed1984

Transition from sensorimotor Stage 5 to Stage 6 by Down syndrome children: a response to Gibson.

Gibson (1978) has suggested that the transition from Sensorimotor Stage 5 to Stage 6 (i.e., the change from exclusive dependence on overt forms of representation and trial-and-error problem-solving to the beginning of internal representation and foresight in problem-solving) is particularly difficult for Down syndrome children. In order to test this "developmental wall" hypothesis, we compared longitudinally the performance of Down syndrome and nonretarded children on the Uzgiris and Hunt (1975) Object Permanence and Means-Ends Relations Scales. Results indicated that in contrast to Gibson's suggestion, the Down syndrome children progressed from Sensorimotor Stage 5 to Stage 6 at the same rate that nonretarded children did, once the generally slower developmental pace of the Down syndrome children was taken into account.

Child Development↗