Inference for quantile measures of kurtosis,peakedness, and tail weight

Insight into measures of peakedness, heavy-tailedness, and kurtosis can be gained by studying Ruppert’s ratios of interquantile ranges. They are not only monotone in Horn’s measure of peakedness when applied to the central portion of the population, but also monotone in the practical tail-index of Morgenthaler and Tukey, when applied to the tails. Non-parametric confidence intervals are found for Ruppert’s ratios, and sample sizes required to obtain such intervals for a pre-specified relative width and level are provided. In addition, the empirical power of distribution-free tests for peakedness and bimodality are found for some symmetric distributions.     

Social Norms and Motivations Associated with College Binge Drinking*

This study proposes that members of Greek social organizations have higher rates of binge drinking as compared to other college students because of their unique social organization, which supports binge drinking. Using data from the College Alcohol Study, logistic regression analysis results show that Greek members binge drink at higher levels than do other students, which supports previous literature ( Cashin, Presley, and Meilman 1998 ). The results also indicate, however, that social norms and motives for drinking which were thought to be predictive of binge drinking practices for all students are actually better predictors of binge drinking for non‐Greek members.     

Observational Stance as a Predictor of Subjective and Genital Sexual Arousal in Men and Women

Observational stance refers to the perspective a person takes while viewing a sexual stimulus, either as a passive observer (observer stance) or an active participant (participant stance). The objective of the current study was to examine the relationship between observational stance and sexual arousal (subjective and genital) across a range of sexual stimuli that do or do not correspond with a participant's sexual attraction (preferred or nonpreferred stimuli, respectively). Regression analyses revealed that, for men (n = 44), participant stance significantly predicted subjective and genital arousal. Women's (n = 47) observer and participant stance predicted subjective arousal but not genital arousal. Analysis of variance showed that participant stance was greatest under preferred sexual stimuli conditions for all groups of participants, while observer stance scores revealed a less consistent pattern of response. This was particularly true for opposite-sex-attracted women, whose ratings of observer stance were lowest for preferred stimuli. Observational stance does not appear to account for gender differences in specificity of sexual arousal; for men, however, participant stance uniquely predicted genital response after controlling for sexual attractions. Similarities in the relationships between men's and women's observational stance and sexual responses challenge previous claims of gender differences in how men and women view erotica.     

Physiological Responses to Near-Miss Outcomes and Personal Control During Simulated Gambling

Near-miss outcomes during gambling are non-win outcomes that fall close to a pay-out. While objectively equivalent to an outright miss, near-misses motivate ongoing play and may therefore be implicated in the development of disordered gambling. Given naturalistic data showing increases in heart rate (HR) and electrodermal activity (EDA) during periods of real gambling play, we sought to explore the phasic impact of win, near-miss and full-miss outcomes on physiological arousal in a controlled laboratory environment. EDA and HR were monitored as healthy, student participants (n = 33) played a simulated slot-machine task involving unpredictable monetary wins. A second gambling distortion, perceived personal control, was manipulated within the same task by allowing the participant to select the play icon on some trials, and having the computer automatically select the play icon on other trials. Near-misses were rated as less pleasant than full-misses. However, on trials that involved personal choice, near-misses produced higher ratings of ‘continue to play’ than full-misses. Winning outcomes were associated with phasic EDA responses that did not vary with personal choice. Compared to full-misses, near-miss outcomes also elicited an EDA increase, which was greater on personal choice trials. Near-misses were also associated with greater HR acceleration than other outcomes. Near-miss outcomes are capable of eliciting phasic changes in physiological arousal consistent with a state of subjective excitement, despite their objective non-win status.     

Stream salamander responses to varying degrees of urbanization within Maryland’s piedmont physiographic province

The main objective of this study was to determine how stream salamander assemblages and species respond to varying levels of impervious surface cover within Maryland’s Piedmont physiographic province. We sampled stream salamanders in 21 first-order streams located in watersheds representing a range of impervious surface cover (0–24 %) across the northeastern part of Maryland’s Piedmont region. Habitat data, including stream substrate and riparian characteristics, were measured at each site. Eurycea bislineata was the predominant species of stream salamander encountered during this study (> 99 % of individuals) and most of these individuals were larvae (> 92 %). Consequently, statistical analysis was limited to E. bislineata larvae. We were unable to detect a difference in E. bislineata abundances or body mass index’s among varying levels of impervious surface cover % or any individual site habitat variables alone. These results suggest that in smaller watersheds within the Piedmont of Maryland, local habitat variables, in conjunction with land use variables, are necessary in determining the abundance and body mass index of E. bislineata larvae populations. This study makes a strong case for halting the over-simplification of the relationship between urbanization and the presence/abundance of stream salamanders.

     

Infusing Career Development to Strengthen Middle School English Language Arts Curricula

An approach is presented for strengthening middle school standards‐based English language arts (ELA) classroom instruction by infusing theory‐ and research‐supported career development constructs and practices. Over an 8‐week period, 90 urban 7th graders participated in an integrated ELA–career development curriculum. Career agency emerged as an important construct for students. It was related to key markers of ELA achievement (i.e., standardized test scores, grades, and positive change in 6th‐ to 7th‐grade test scores) and elaborated on in nuanced ways by students in their written narratives. Four themes related to career agency were identified in student writings: time perspective, challenges of self‐direction, career development, and social and emotional development. Advantages for students and schools related to synergy, scale, and sustainability are discussed.     

Toddlers Help Anonymously

Young children are extremely motivated to help others, but it is not clear whether they do so in anonymous situations without social recognition. In two studies, we found that 18‐month‐old toddlers provided help equally in situations where an adult recipient was present and in situations where an adult recipient was not present. We included several control conditions to rule out that toddlers were simply unaware of their anonymity or were merely motivated to restore the physical order of things. Together, these findings suggest that early in ontogeny children are motivated to help others in need regardless of whether they can immediately be recognized for their prosocial intentions.