Eat,drink, and be merry,for tomorrow we diet: effects of anticipated deprivation on food intake in restrained and unrestrained eaters

This study examined the effect of anticipated food deprivation on intake in restrained and unrestrained eaters. Participants were randomly assigned to a diet condition, in which they expected to diet for a week, or to a control (no-diet) condition. Immediately after being assigned to a condition, participants completed a taste-rating task in which food consumption was measured. Restrained eaters in the diet condition consumed significantly more food than did restrained eaters in the no-diet condition or unrestrained eaters in either condition. Unrestrained eaters consumed the same amount regardless of condition. These results confirm that merely planning to go on a diet can trigger overeating in restrained eaters, reflecting the dynamic connection between dieting and overeating.     

Clinical features of major depressive disorder in adolescents and their relatives: impact on familial aggregation, implications for phenotype definition, and specificity of transmission

Three questions were addressed using family study data from a community sample: (a) Which clinical features of major depressive disorder (MDD) in adolescents are associated with elevated rates of MDD in relatives? (b) Which features of MDD in relatives distinguish family members of depressed adolescents from relatives of adolescents without mood disorders (NMD)? and (c) Do depressed adolescents with particular features have higher proportions of depressed relatives with the same features? Participants included 268 MDD adolescents, 401 NMD adolescents, and their 2,202 first-degree relatives. Rates of MDD were highest among relatives of depressed adolescents with recurrent episodes and greater impairment. Depression severity best distinguished the relatives of depressed adolescents from relatives of controls. Specific clinical features did not aggregate in families.     

Molecular analyses of the principal components of response strength

Killeen and Hall (2001) showed that a common factor called strength underlies the key dependent variables of response probability, latency, and rate, and that overall response rate is a good predictor of strength. In a search for the mechanisms that underlie those correlations, this article shows that (a) the probability of responding on a trial is a two-state Markov process; (b) latency and rate of responding can be described in terms of the probability and period of stochastic machines called clocked Bernoulli modules, and (c) one such machine, the refractory Poisson process, provides a functional relation between the probability of observing a response during any epoch and the rate of responding. This relation is one of proportionality at low rates and curvilinearity at higher rates.     

Sex differences in performance on three novel continuous response tasks

The Dynavision apparatus was used to assess psychomotor differences between men and women first-time users. Subjects, 50 men and 76 women, were tested on three 60-sec. Dynavision response tasks of graded difficulty. An analysis of variance with repeated measures indicated that men performed significantly better than women on all tasks. Performances on all tasks were also significantly different from each other within both sexes (p < or = .05). Furthermore, a significant interaction between sex and task was based on a greater drop in performance on the most complex task for women than for men.     

Symptoms of anxiety disorders and teacher-reported school functioning of normal children

Correlations between scores on the Spence Children's Anxiety Scale, a questionnaire for measuring symptoms of anxiety disorders and a report of school functioning by teachers were computed for 317 primary school children and 13 teachers in The Netherlands. Analysis showed a small but significant negative correlation between scores for total anxiety and school functioning (r = -.20, p < .001). The finding is consistent with the notion that high symptoms indicating anxiety disorders in children are accompanied by less optimal functioning in school.     

On normal theory based inference for multilevel models with distributional violations

Data in social and behavioral sciences are often hierarchically organized though seldom normal, yet normal theory based inference procedures are routinely used for analyzing multilevel models. Based on this observation, simple adjustments to normal theory based results are proposed to minimize the consequences of violating normality assumptions. For characterizing the distribution of parameter estimates, sandwich-type covariance matrices are derived. Standard errors based on these covariance matrices remain consistent under distributional violations. Implications of various covariance estimators are also discussed. For evaluating the quality of a multilevel model, a rescaled statistic is given for both the hierarchical linear model and the hierarchical structural equation model. The rescaled statistic, improving the likelihood ratio statistic by estimating one extra parameter, approaches the same mean as its reference distribution. A simulation study with a 2-level factor model implies that the rescaled statistic is preferable.This research was supported by grants DA01070 and DA00017 from the National Institute on Drug Abuse and a University of North Texas faculty research grant. We would like to thank the Associate Editor and two reviewers for suggestions that helped to improve the paper.     

A contour propagation approach to surface filling-in and volume formation

A new approach to surface and volume formation is introduced in response to the question, "Why do some silhouettes look 3 dimensional (3D) and others look 2D?" The central idea is that form information can propagate away from a "propagable segment" (PS) of occluding contour that could have projected onto the image from the visible portion of a cross-section of a surface. A key property of a PS is that it exhibits abrupt curvature changes where it meets the rest of the occluding contour. An algorithm is described for filling in curved surfaces from a PS: When copies of a PS are propagated into the interior, they act as cross-sectional surface contours that also exhibit abrupt curvature changes with the rest of the occluding contour. The result is a nonmetric coding of 3D-shape in terms of local ordinal surface curvature and orientation relationships that is scale, translation, and rotation invariant.     

A unified approach to exploratory factor analysis with missing data,nonnormal data,and in the presence of outliers

Factor analysis is regularly used for analyzing survey data. Missing data, data with outliers and consequently nonnormal data are very common for data obtained through questionnaires. Based on covariance matrix estimates for such nonstandard samples, a unified approach for factor analysis is developed. By generalizing the approach of maximum likelihood under constraints, statistical properties of the estimates for factor loadings and error variances are obtained. A rescaled Bartlett-corrected statistic is proposed for evaluating the number of factors. Equivariance and invariance of parameter estimates and their standard errors for canonical, varimax, and normalized varimax rotations are discussed. Numerical results illustrate the sensitivity of classical methods and advantages of the proposed procedures.This project was supported by a University of North Texas Faculty Research Grant, Grant #R49/CCR610528 for Disease Control and Prevention from the National Center for Injury Prevention and Control, and Grant DA01070 from the National Institute on Drug Abuse. The results do not necessarily represent the official view of the funding agencies. The authors are grateful to three reviewers for suggestions that improved the presentation of this paper.     

The optic trajectory is not a lot of use if you want to catch the ball

According to linear optic trajectory (LOT) theory, fielders use the direction of curvature of theoptic trajectory to control the way they run to intercept the ball. Data presented by D. M. Shaffer and M. K. McBeath (2002) as support for LOT theory show that the optic trajectory of balls that will fall behind the fielder provide the cue that LOT theory predicts would send the fielder running forward, not backward. In this article, the authors show that watching these balls would provide the fielder with the cue that the optic acceleration cancellation (OAC) theory of interception predicts would send the fielder running backward. It appears that the fielders studied by Shaffer and McBeath were following the cue predicted by OAC theory, not that predicted by LOT theory.