The size-constancy of underwater swimmers

The size-constancy of divers was measured by requiring them to adjust the distance between two disks of unequal size so that they appeared phenomenally equal. In clear water divers showed greater constancy-ratios than on land. In murky water, where visibility was reduced by suspended particles, constancy-ratios were the same as, or less than, on land. It is suggested that these effects may be due to changes in apparent distance: in clear water objects appear nearer through refraction, but in murky water they appear further away because of the distance cues provided by the visibility gradient.

The orientation of the display, or of the diver's body, did not affect constancy under water, though it does on land. It is argued that the effect on land is due to visual and proprioceptive cues which are absent in the water.     

Psychosocial Predictors of Young Adolescent Cigarette Smoking: A Sixteen-Month,Three-Wave Longitudinal Study1

Understanding the psychosocial factors that predict cigarette smoking onset in young people is of crucial importance for prevention efforts. The present study examined prospective psychosocial predictors of smoking in a three-wave longitudinal data set. Similar in design to an earlier study by Chassin, Presson, Sherman, Corty, and Olshavsky (1984), the present study replicated their work, and extended it by (a) using composite predictors derived from exploratory factor analysis, (b) including prior behavior as a predictor, (c) using a design extended over three waves of data collection, and (d) using a sample composed primarily of urban teenagers. Subjects were 3295 7th-grade students at the beginning of the study. The subjects completed a questionnaire containing items tapping cigarette smoking behavior and psychosocial items that have previously been shown to predict smoking behavior. Forty-one psychosocial items on the Wave 1 (initial) questionnaire were factor analyzed, and five factors were retained. Subscale scores were constructed based on these factors and were used as predictors. Regression analyses were performed using the subscales and pretest smoking frequency to predict a continuous measure of smoking, and discriminant analyses were performed to predict transitions between qualitative levels of smoking. Prior smoking behavior was the most important predictor of future smoking. Four of the subscales, Social Disapproval, Risk Taking/Rebelliousness, Perceived Smoking Prevalence, and Motivation to Comply, were significant predictors. One subscale, Physical Consequences from Smoking, was not predictive of smoking in any of the analyses. The effect sizes cross-validated well. It is suggested that an integrative model of smoking initiation developed by Flay, d'Avernas, Best, Kersell, and Ryan (1983) best summarizes the results of the present study.     

Some Effects of Reduction of Extra-Classroom Crowding in a School Environment

The effects of reduced enrollment were studied by examining two architecturally identical schools. One school experienced a 43% reduction in enrollment while the other's enrollment remained constant. Reduction in enrollment had a number of positive benefits, including improved attitudes about the school environment and reduced faculty absenteeism. Findings regarding academic performance were less clear.     

Dynamic changes in work/rest duty cycles in a study of sleep deprivation

The effects of moderate workload and 72 h of sleep deprivation were studied using a modified continuous-performance paradigm. Ten subjects were tested hourly on a number of perceptual and cognitive tasks designed to require approximately 30 min to complete, with the remainder of each hour free. As sleep deprivation continued, the average time on task increased at an accelerating rate. The rate of increase differed among tasks, with longer tasks showing greater absolute and relative increases than shorter ones. Such increases confound sleep deprivation and workload effects. In this paper, we compare the advantages and disadvantages of several experimental paradigms; describe details of the present design; and discuss methodological problems associated with separating the interactions of sleep deprivation, workload, and circadian variation with performance.     

Training Methods for Delivering Difficult News in Genetic Counseling and Genetics Residency Training Programs

Genetic counselors and clinical geneticists are often in the position of delivering difficult news (DDN) to patients and families. Many studies show that healthcare providers require major improvement in the skills needed in DDN in a manner that is satisfactory to their patients. The purpose of this study was to assess the amount and methodology of DDN training received by genetic counselors and medical genetics residents in their training programs, such as observations of DDN or attending didactic lectures. To our knowledge, there is no previous assessment or study of DDN training in genetic counselor and medical genetics residency programs; therefore, we aim to both assess and compare the training in DDN received by genetic counselors and by genetics residents and determine whether there is a desire for recommendations on DDN training. We invited genetic counseling (GC) and genetics residency program directors to participate in an online survey designed to assess coursework, clinical experiences, and directors’ attitudes toward teaching DDN. Response rate was 85% (28/33) for GC program directors and 26% (14/53) for genetics residency program directors. One hundred percent of GC and genetics residency directors who responded to the survey agreed that it is important for genetic counselors and medical geneticists to be able to deliver difficult news effectively and that training programs should formally teach students how to deliver difficult news. Six of the eight common teaching methods are used by at least 75% of GC programs while two of eight are used by at least 75% of genetics residency programs. Seventy-nine percent of GC and 93% of genetics residency program directors agree that there should be recommendations on how to teach students to deliver this news. Our results show that techniques for DDN are integrated more fully into GC program curricula than genetics residency curricula. Directors of both types of programs desire recommendations and more standardized education for training students to deliver difficult news.     

Bayesian inference for psychology. Part II: Example applications with JASP

Bayesian hypothesis testing presents an attractive alternative to p value hypothesis testing. Part I of this series outlined several advantages of Bayesian hypothesis testing, including the ability to quantify evidence and the ability to monitor and update this evidence as data come in, without the need to know the intention with which the data were collected. Despite these and other practical advantages, Bayesian hypothesis tests are still reported relatively rarely. An important impediment to the widespread adoption of Bayesian tests is arguably the lack of user-friendly software for the run-of-the-mill statistical problems that confront psychologists for the analysis of almost every experiment: the t-test, ANOVA, correlation, regression, and contingency tables. In Part II of this series we introduce JASP (http://www.jasp-stats.org), an open-source, cross-platform, user-friendly graphical software package that allows users to carry out Bayesian hypothesis tests for standard statistical problems. JASP is based in part on the Bayesian analyses implemented in Morey and Rouder’s BayesFactor package for R. Armed with JASP, the practical advantages of Bayesian hypothesis testing are only a mouse click away.