Infants' Ability to Learn Phonetically Similar Words: Effects of Age and Vocabulary Size

What do novice word learners know about the sound of words? Word‐learning tasks suggest that young infants (14 months old) confuse similar‐sounding words, whereas mispronunciation detection tasks suggest that slightly older infants (18–24 months old) correctly distinguish similar words. Here we explore whether the difficulty at 14 months stems from infants' novice status as word learners or whether it is inherent in the task demands of learning new words. Results from 3 experiments support a developmental explanation. In Experiment 1, infants of 20 months learned to pair 2 phonetically similar words to 2 different objects under precisely the same conditions that infants of 14 months (Experiment 2) failed. In Experiment 3, infants of 17 months showed intermediate, but still successful, performance in the task. Vocabulary size predicted word‐learning performance, but only in the younger, less experienced word learners. The implications of these results for theories of word learning and lexical representation are discussed.     

Childhood Developmental Risk for Teen Childbearing in Britain

Adolescence is often assumed to be the most important period of life for understanding teen childbearing risk. Developmental perspectives challenge that assumption, offering the possibility that early childhood characteristics may have unique and lasting effects on the risk for teen childbearing. This study examined family life risk factors (socioeconomic status, family stress, and parental involvement in education) and how their effects on teen childbearing risk varied, depending on the childhood age at which they were experienced. Prospective life history data from the National Child Development Study of Great Britain were used to study a birth cohort of 4,928 British women, 15.3% of who became pregnant as teens. This study demonstrated that data from early childhood significantly contribute to the understanding of teen childbearing risk.     

Factors Associated with the Development of Nonmetropolitan Growth Nodes in Producer Services Industries, 1980–1990*

Abstract Over the 1980–1990 period, employment in producer services industries in the nonmetropolitan United States increased substantially. This growth resulted in the development of nonmetropolitan growth nodes in producer services industries. A growth node refers to a nonmetropolitan area that contains a greater than average concentration of employment in a particular industry sector relative to other nonmetropolitan areas. Moreover, this industry concentration not only increases over time, but also represents an important source of employment growth within the area. With nonmetropolitan counties as the spatial unit of analysis, 317 growth nodes in producer services industries are identified for the 1980–1990 period. Access to workers with clerical and administrative support skills, access to highly educated workers, higher earnings per employed worker, access to recreational amenities, and proximity to metropolitan areas were associated with the development of nonmetropolitan growth nodes in producer services industries during this period.     

Review Essay: The Political Sociology of Nader and Chomsky

Sociological Forum -     

Local polynomial estimation of Poisson intensities in the presence of reporting delays

Summary.  The system for monitoring suicides in Hong Kong has considerable delays in reporting as the cause of death needs to be determined by a coroner's investigation. However, timely estimates of suicide rates are desirable to assist in the formulation of public health policies. This motivated us to develop a non-parametric procedure to estimate the intensity function of a Poisson process in the presence of reporting delays. We give closed form estimators of the Poisson intensity and the delay distribution, conduct simulation studies to evaluate the method proposed and derive their asymptotic properties. The method proposed is applied to estimate the intensity of suicide in Hong Kong.     

Plaid designs for the evaluation of training for medical practitioners

The training of medical practitioners to improve the practitioner/patient relationship may be difficult, as limitations often exist on the choice of patients included in the study. A specific study of this type of training is given. It is proposed that a simple modification and generalization of Yates' plaid-square designs be used. It is shown that a replicated plaid-design incorporates as a special case the criss-cross or strip-plot design. The usefulness of these designs in studies of the training of medical practitioners is illustrated. The basic characteristics of their analysis are outlined.