A comparison of various forms of reinforcement with and without extinction as treatment for escape-maintained problem behavior

The present investigation compared the effects of reinforcing compliance with either positive or negative reinforcement for a participant who displayed escape-maintained problem behavior. The results indicated that positive reinforcement in the form of a highly preferred edible or leisure item produced higher levels of compliance and lower levels of problem behavior when compared to negative reinforcement in the form of escape from demands. In addition, an extinction procedure was unnecessary to achieve high levels of compliance.     

An exploratory examination of the associations among racial and ethnic discrimination, racial climate, and trauma-related symptoms in a college student population

In this study, we examined the association among perceptions of racial and/or ethnic discrimination, racial climate, and trauma-related symptoms among 289 racially diverse college undergraduates. Study measures included the Perceived Stress Scale, the Perceived Ethnic Discrimination Questionnaire, the Posttraumatic Stress Disorder Checklist-Civilian Version, and the Racial Climate Scale. Results of a multivariate analysis of variance (MANOVA) indicated that Asian and Black students reported more frequent experiences of discrimination than did White students. Additionally, the MANOVA indicated that Black students perceived the campus racial climate as being more negative than did White and Asian students. A hierarchical regression analysis showed that when controlling for generic life stress, perceptions of discrimination contributed an additional 10% of variance in trauma-related symptoms for Black students, and racial climate contributed an additional 7% of variance in trauma symptoms for Asian students.     

Preschoolers' knowledge about the appearance of proper names

Preschoolers' knowledge of the appearance of proper names was tested in three experiments with 25 boys and 22 girls from low-income families. Children from a Head Start program, whose parents signed a permission letter, participated. Their ages ranged from 3 yr. 6 mo. to 5 yr. 6 mo. (M = 52.2 mo., SD = 4.9). When shown consonant-vowel-consonant trigrams such as Rit or baF or dEg with various capitalization patterns, the children showed a tendency to recognize that CVC trigrams with the first letter capitalized or all letters capitalized were the ones most likely to represent a person's name. When their own names were substituted, which typically contained more than three letters, their performance was markedly better. Children also had a strong tendency to consider trigrams of Latin letters as more likely to be a person's name than trigrams of non-Latin characters (e.g., Sanskrit).     

Internalizing Trajectories in Young Boys and Girls: The Whole is Not a Simple Sum of its Parts

There is support for a differentiated model of early internalizing emotions and behaviors, yet researchers have not examined the course of multiple components of an internalizing domain across early childhood. In this paper we present growth models for the Internalizing domain of the Infant-Toddler Social and Emotional Assessment and its component scales (General Anxiety, Separation Distress, Depression/Withdrawal, and Inhibition to Novelty) in a sample of 510 one- to three-year-old children. For all children, Internalizing domain scores decreased over the study, although girls had significantly higher initial levels and boys had steeper declines. General Anxiety increased over the study period and, when modeled individually, girls evidenced higher initial levels and greater increases. For all children, Separation Distress and Inhibition to Novelty decreased significantly over time, while Depression/Withdrawal remained low without change. Findings from our parallel process model, in which all components were modeled simultaneously, revealed that initial levels of internalizing scales were closely associated while rates of change were less closely related. Sex differences in variability around initial levels and rates of change emerged on some scales. Findings suggest that, for one- to three-year-olds, examining scales of the internalizing domain separately rather than as a unitary construct reveals more meaningful developmental and gender variation.     

The observation of stacking-fault tetrahedra in III-V compounds

Abstract

The first observations of stacking-fault tetrahedra in ion-implanted III-V compounds are reported. The structure and orientation of the stacking-fault tetrahedra are briefly described. The tetrahedra are present in the near-surface region that recrystallized during the annealing. High-resolution images suggest that the stacking-fault tetrahedra are of the vacancy type.     

Hierarchical models for relational event sequences

Interaction within small groups can often be represented as a sequence of events, each event involving a sender and a recipient. Recent methods for modeling network data in continuous time model the rate at which individuals interact conditioned on the previous history of events as well as actor covariates. We present a hierarchical extension for modeling multiple such sequences, facilitating inferences about event-level dynamics and their variation across sequences. The hierarchical approach allows one to share information across sequences in a principled manner—we illustrate the efficacy of such sharing through a set of prediction experiments. After discussing methods for adequacy checking and model selection for this class of models, the method is illustrated with an analysis of high school classroom dynamics from 297 sessions.     

Effects of Emotional Factors Upon Recall

Bendig's (1) Pittsburgh Scales of Social Extraversion-Introversion (SEI) and Emotionality (Em) were translated so that they were of appropriate reading difficulty for children as well as for adults. The revised scales correlated highly (both .90) with the Pittsburgh scales, and they had high test-retest reliabilities (.92 and .89). Data from samples representing third grade to college ages were presented for the revised scales. SEI-Em correlations were nonsignificant for most subsamples, indicating that the revised SEI-Em scales are independent. Scale means were stable across ages. The revised scales should be considered as research instruments, since more representative normative data and validity data are still required. The scales should, though, facilitate developmental research in extraversion and emotionality.     

Social problem solving in early childhood: Developmental change and the influence of shyness

The purpose of this study was to examine developmental change and the influence of shyness on social problem-solving (SPS). At 24, 36, and 48 months, children (N = 570) were observed while interacting with an unfamiliar peer during an SPS task and at 24 months, maternal report of shyness was collected. Results showed that across the full sample, children displayed low but stable levels of withdrawn SPS and increasing levels of SPS competence over development. In addition, results showed multiple trajectories of withdrawn and competent SPS. Shyness was associated with high-increasing and high-decreasing withdrawn SPS trajectories compared with the low-increasing withdrawn SPS trajectory. Shyness was also associated with the low-increasing compared with the high-increasing SPS competence trajectory. Findings demonstrate the development of SPS competence over early childhood, and the influence of early shyness on this developmental course, with some shy children showing improvement in SPS skills and others continuing to show SPS difficulties over time.