Wallace E. Dixon

Temperamental predictors of linguistic style during multiword acquisition

Abstract To investigate temperamental predictors of linguistic style, parents of 29 13-month-olds completed the Rothbart Infant Behavior Questionnaire and were later interviewed about their childrens language. Three temperamental dimensions predicted analytic/referential language. Temperament may contribute to parent–child relationships conductive to acquisition of nominals.

Temperamental and Joint Attentional Predictors of Language Development

Individual differences in child temperament have been associated with individual differences in language development. Similarly, relationships have been reported between early nonverbal social communication (joint attention) and both temperament and language. The present study examined whether individual differences in joint attention might mediate temperament-language relationships. Temperament, language, and joint attention were assessed in 51 21-month-olds. Results indicated an inverse relationship between aspects of temperamental difficulty, including low executive control and high negative affect, and language development. Temperamental aspects of negative affect were also inversely predictive of joint attention. However, the utility of a model in which joint attention mediates the relationship between temperament and language during the second year was not supported.

TouchStat: A Monte Carlo program for calculating sequential touching probabilities

A growing number of child cognition researchers are using an object-manipulation, sequential-touching paradigm to explore young children’s conceptual abilities. Within this paradigm, it is essential to distinguish children’s intracategory touching sequences from those expected by chance. The sequentialtouching approach is congruent with a permutation testing model of statistical inference and is best modeled by sampled permutations as derived from Monte Carlo procedures. In this article, we introduce a computer program for generating Monte Carlo sequential-touching simulations. TouchStat permits users to determine their own specifications to simulate sequential touching to category exemplars across a wide range of task parameters. We also present Monte Carlo chance probabilities for the standard two-category, four-exemplar task, with sequences up to 30 touches long. Finally, we consider broader applications of the TouchStat program.

Establishing covariance continuity between the WISC--R and the WISC-III.

Much of the research based on Wechsler Intelligence Scale for Children-Revised (WISC-R; D. Wechsler, 1974) subtest covariances may not validly be applied to the Wechsler Intelligence Scale for Children-Third Edition (WISC-III; D. Wechsler, 1991) without ascertaining whether the covariance structures of the normative samples for the two versions are equivalent. The covariance matrices for the WISC-R and the WISC-III were tested for equality by age group using the EQS Structural Equations Program (P. M. Bentler, 1989). Chi-square tests revealed significant differences between the covariance matrices for 10- and 16-year-olds; however, the more stable normed fit index revealed essentially no difference across all age groups. It can be concluded that, for all practical purposes, covariation among WISC-III subtests does not differ from covariation among WISC-R subtests

TouchStat v. 3.00: a new and improved Monte Carlo adjunct for the sequential touching task.

The sequential-touching procedure is employed by researchers studying nonlinguistic categorization in toddlers. TouchStat 3.00 is introduced in this article as an adjunct to the sequential-touching procedure, allowing researchers to compare children’s actual touching behavior to what might be expected by chance. Advantages over the Thomas and Dahlin (2000) framework include ease of use, and fewer assumptive limitations. Improvements over TouchStat 1.00 include calculation of chance probabilities for multiple “special cases” and for immediate intercategory alternations. A new feature for calculating mean run length is also included.

Infants' responses to objects representing levels of word knowledge and categorical information

Abstract The effects of differing levels of word knowledge on infants’ sequential touching behaviors were investigated in two studies. In both, parent report was used to assess three levels of word knowledge: known, frontier, and unknown. In the first study, 14-month-old infants sequentially touched objects consistent with parents’ reports of their word knowledge. In the second study, 20-month-old infants sequentially touched objects by both conceptual category and reported level of word knowledge. It appears that even infants, like adults, can make distinctions among objects on the basis of their knowledge about the objects’ labels.

CHILDREN'S ACQUISITION OF LANGUAGE: GENERAL LINGUISTIC COMPETENCE OR DIMENSIONS OF STYLE?

Previous studies have described children’s acquisition of language as reflecting either a referential or an expressive style. A multivariate approach, characterizing “referentiality” and “expressivity” as partially dissociable dimensions, is advantageous because it allows children to vary along one dimension as they vary along another, allowing children to have high or low degrees of both characteristics simultaneously. The present study applies multivariate techniques to an “exploratory” sample of 87 children, all of whom were 20 months old, and by subsequently validating the exploratory phase with 56 of the original children seen one month later. Using parental reports to assess children’s multiword productions, exploratory factor analyses revealed two correlated dimensions of language style which indeed reflected referential and expressive characteristics. Confirmatory factor analyses “confirmed” these factors in the test sample. This two-dimensional model of language acquisition was superior to a unidimensional, general linguistic competence model. There is also strong short-term stability for both dimensions across the one-month period.