Testing the effects of an expectancy-based intervention among adolescents: Can placebos be used to enhance physical health?

It has been suggested that the well-known health benefits associated with exercise can be explained by a placebo effect, and that greater effort should be given to convince people that their current behaviors have desirable health consequences. The overall purpose of this study was to test the efficacy of this "mind-set matters" hypothesis through the use of an expectancy-based intervention with adolescents. The study involved a four week randomized controlled trial with 348 Grade 9 adolescents (M (age)?=?14.07 yrs, SD?=?0.30), from four high schools, taking part in either a placebo-intervention condition (n?=?188) or a control condition (n?=?160). Participants in the placebo-intervention condition were informed that what they are already doing in school physical education lessons fulfills current recommendations for an active lifestyle. Participants in the control condition were not given this information. Four weeks after the intervention, adolescents in the placebo-intervention condition did not demonstrate significant changes in physiological health-related measures (diet, weight, body mass index, percentage body fat, heart rate, mean arterial pressure). The findings question the external validity of the "mind-set matters" hypothesis with adolescents, and suggest that simply encouraging adolescents to believe that they are healthy may not enable them to respond with improved indicators of physical health.     

Age-related differences in inhibitory control in the early school years

The transition to school is associated with a greater requirement to inhibit irrelevant or inappropriate thought and behavior in order to concentrate on effective learning and to interact successfully with peers. Current knowledge of inhibitory control development in the early school years is limited due to a lack of normative data from age-appropriate, sensitive measures. In this study, three pictorial versions of the Stroop task were administered to investigate inhibitory control development in early school-aged children. Age-related trajectories of inhibition and effects of gender were examined in 80 children (42 boys) aged 5 to 8 years. All children were assessed with the Cognitive Assessment System Expressive Attention subtest (Big-Small Stroop), Fruit Stroop, and Boy-Girl Stroop. The Big-Small Stroop revealed substantial age-related improvement in inhibition from 5 to 7 years with a levelling of performance at 8 years of age, while the Fruit Stroop and Boy-Girl Stroop demonstrated clear but nonsignificant age trends. In particular, older children committed fewer errors and corrected their errors more frequently than younger children. Performance on all Stroop tasks correlated significantly, providing evidence that they tap similar cognitive abilities. Some gender differences were found. This study indicates that inhibitory skills develop rapidly in the early school years and suggests that error awareness may be a useful indicator of the development of cognitive inhibition for this age group.     

Olfactory discrimination of mouse strains (Mus musculus) and major histocompatibility types by humans (Homo sapiens)

A series of experiments revealed that humans can use olfaction to discriminate closely related strains of mice, differing genetically only at the major histocompatibility gene complex (H-2). In Experiment 1, subjects were asked to distinguish between the whole-body odors of live mice. In Experiments 2 and 3, the odor source was mouse fecal pellets, and in Experiments 4 and 5, the odor source was mouse urine.     

Body dissatisfaction,eating disorders,and depression: A developmental perspective

McCarthy (1990) contends that a cultural ideal of thinness (the thin ideal) causes depression and eating disorders to occur more frequently in women than men. She believes eating disorders are a way of coping with depression and hypothesizes that the thin ideal has its greatest impact during puberty when sexual attractiveness becomes important and changes in physical appearance increase the discrepancy between the adolescent girl's actual and ideal body image. The present study used a cross-sectional design of 5th, 8th, and 12th grade males and females (N = 599) to test several predictions from McCarthy's model. As expected, 8th and 12th grade females preferred a thinner than average body shape. They were more dissatisfied with their bodies than males and scored higher on measures of disordered eating. In contrast, before puberty (5th grade) boys were more depressed than their female peers but this pattern was reversed in 8th grade boys and girls. Paralleling changes in depression, disordered eating scores were highest in 8th and 12th grade girls. Both of these findings underscore the role of maturational factors in the onset of eating disorders. Although the sample was ethnically diverse and mainly from middle and low socioeconomic groups, there was a surprisingly high incidence of body dissatisfaction and symptoms of disordered eating. This illustrates the pervasiveness of thinness as a standard of feminine beauty in our society and the damaging effects it can have.     

The mettle of moral fundamentalism: a reply to Robert Baker

This article is a reply to Robert Baker's attempt to rebut moral fundamentalism, while grounding international bioethics in a form of contractarianism. Baker is mistaken in several of his interpretations of the alleged moral fundamentalism and findings of the Advisory Committee on Human Radiation Experiments. He also misunderstands moral fundamentalism generally and wrongly categorizes it as morally bankrupt. His negotiated contract model is, in the final analysis, itself a form of the moral fundamentalism he declares bankrupt.     

In Defense of Affirmative Action

Affirmative action refers to positive steps taken to hire persons from groups previously and presently discriminated against. Considerable evidence indicates that this discrimination is intractable and cannot be eliminated by the enforcement of laws. Numerical goals and quotas are justified if and only if they are necessary to overcome the discriminatory effects that could not otherwise be eliminated with reasonable efficiency. Many past as well as present policies are justified in this way.