Effects of category learning on the stimulus selectivity of macaque inferior temporal neurons

Primates can learn to categorize complex shapes, but as yet it is unclear how this categorization learning affects the representation of shape in visual cortex. Previous studies that have examined the effect of categorization learning on shape representation in the macaque inferior temporal (IT) cortex have produced diverse and conflicting results that are difficult to interpret owing to inadequacies in design. The present study overcomes these issues by recording IT responses before and after categorization learning. We used parameterized shapes that varied along two shape dimensions. Monkeys were extensively trained to categorize the shapes along one of the two dimensions. Unlike previous studies, our paradigm counterbalanced the relevant categorization dimension across animals. We found that categorization learning increased selectivity specifically for the category-relevant stimulus dimension (i.e., an expanded representation of the trained dimension), and that the ratio of within-category response similarities to between-category response similarities increased for the relevant dimension (i.e., category tuning). These small effects were only evident when the learned category-related effects were disentangled from the prelearned stimulus selectivity. These results suggest that shape-categorization learning can induce minor category-related changes in the shape tuning of IT neurons in adults, suggesting that learned, category-related changes in neuronal response mainly occur downstream from IT.     

Perceptual saliency of points along the contour of everyday objects: a large-scale study

The aim of this large-scale study was to find out which points along the contour of a shape are most salient and why. Many subjects (N=161) were asked to mark salient points on contour stimuli, derived from a large set of line drawings of everyday objects (N=260). The database of more than 200,000 marked points was analyzed extensively to test the hypothesis, first formulated by Attneave (1954), that curvature extrema are most salient. This hypothesis was confirmed by the data: Highly salient points are usually very close to strong curvature extrema (positive maxima and negative minima). However, perceptual saliency of points along the contour is determined by more factors than just local absolute curvature. This was confirmed by an extensive correlational analysis of perceptual saliency in relation to ten different stimulus factors. A point is more salient when the two line segments connecting it with its two neighboring salient points make a sharp turning angle and when the 2-D part defined by the triplet of salient points is less compact and sticks out more.     

Drive for thinness, affect regulation and physical activity in eating disorders: a daily life study

Using Ecological Momentary Assessment, the within patient associations between drive for thinness, emotional states, momentary urge to be physically active and physical activity were studied in 32 inpatients with an eating disorder. Participants received an electronic device and had to indicate at nine random times a day during 1 week their momentary drive for thinness, positive and negative emotional states and their urge to be physically active and physical activity. Multilevel analyses indicated that patients with higher mean levels for urge to be physically active were characterized by lower body mass index (BMI) and chronically negative affect whereas patients with higher mean levels for physical activity were characterized by lower BMI and higher dispositions for drive for thinness. In addition, within patient relations between drive for thinness and urge to be physically active were moderated by BMI and chronically negative affect whereas within patient relations between drive for thinness and physical activity were moderated by BMI. Finally, also positive emotional states were significantly associated with physical activity within patients. By using a daily process design, characteristics of physical activity were revealed that have not been identified with assessment methods that have a lower time resolution.     

Ethical Theories and the Transparency Condition

Following John Rawls, writers like Bernard Williams and Christine Korsgaard have suggested that a transparency condition should be put on ethical theories. The exact nature of such a condition and its implications is however not anything on which there is any consensus. It is argued here that the ultimate rationale of transparency conditions is epistemic rather than substantively moral, but also that it clearly connects to substantive concerns about moral psychology. Finally, it is argued that once a satisfactory form of the transparency condition is formulated, then, at least among the main contenders within ethical theory, it speaks in favor of a broadly Aristotelian approach to ethical theorizing.     

Being Admired or Being Liked: Classroom Social Status and Depressive Problems in Early Adolescent Girls and Boys

This study investigates associations between depressive problems and classroom social status in a large population cohort of Dutch early adolescents (N = 1046, age 13.52 +/- 0.51, 52.4% girls). Depressive problems were assessed by parent and self-reports and classroom status by peer nominations. We assessed peer status with respect to both achievement-related (being a good learner, being good at sports, being good-looking) and affection-related (being liked, being disliked, being best friend) areas. In boys, depressive problems were most strongly associated with not being good at sports, while in girls the association was strongest for not being liked. The risk of a low status in one area could largely be compensated by a high status in another area.     

Appraisal of behavioral measurement techniques for assessing dental anxiety and fear in children: A review

The aim of this article is to review and evaluate behavioral and physiological measurement techniques frequently used to assess dental anxiety and fear in children. Attention is given to the data collected, the empirical findings obtained, and the availability of normative data. The main focus, however, is on the reliability and validity. Results show that all questionnaires are open to criticism. Of the behavioral measures, Melamed's Behavior Profile Rating Scale is to be preferred to Frankl's Rating Scale, Venham Rating Scales, and Visual Analogue Scales. The main reasons are that Melamed's BPRS measures the behavior of the child more precisely and that it has superior psychometric properties. Furthermore, because of their practical, conceptual, and psychometric problems, physiological measures at this stage are found to be less appropriate for assessing dental fear in children. It is concluded that a behavioral measure is not always the ideal, but often the only available technique for assessing dental fear in children.