Amygdala activation during masked presentation of emotional faces predicts conscious detection of threat-related faces

It has been argued that critical functions of the human amygdala are to modulate the moment-to-moment vigilance level and to enhance the processing and the consolidation of memories of emotionally arousing material. In this functional magnetic resonance study, pictures of human faces bearing fearful, angry, and happy expressions were presented to nine healthy volunteers using a backward masking procedure based on neutral facial expression. Activation of the left and right amygdala in response to the masked fearful faces (compared to neutral faces) was significantly correlated with the number of fearful faces detected. In addition, right but not left amygdala activation in response to the masked angry faces was significantly related to the number of angry faces detected. The present findings underscore the role of the amygdala in the detection and consolidation of memory for marginally perceptible threatening facial expression.     

Perception of illumination direction in images of 3-D convex objects: influence of surface materials and light fields

We investigated the perception of illumination direction in images of 3-D convex objects under variations of light field and surface material properties. In a first experiment, we used an illumination-matching procedure in order to measure observers' ability to estimate the direction of illumination in images of 3-D polyhedra rendered under different light fields and illumination directions. Match deviations were larger in frontal direction than in rear directions, mainly counterclockwise in azimuth component, and diverged, in elevation component, from the image plane. In a second experiment, we examined whether the direction estimate was affected by the surface material type (BRDF), the light field, and the illumination direction. Angular deviations varied with material surface type and were largest in the test elevation direction 0 degrees. Elevation component deviations also differed with surface type and were larger in hemispherical diffuse lighting than in collimated lighting. These results suggest that the direction estimation is better with images of evenly distributed intensity gradients than with those of drastically varying gradients, and that the visual system may not take intensity variations due to the surface material or the light field into account in estimating the direction of illumination.     

Visual search for size-defined target objects is modulated by the Ebbinghaus apparent-size illusion: facilitatory and inhibitory effects of the context objects

Five experiments were carried out to investigate under which conditions the apparent size of objects is computed and exploited optimally in visual search for size-defined targets. Observers searched for a target test circle that was retinally larger than the distractor test circles, with both types of circles surrounded by context circles modulating the apparent size of the test circles (Ebbinghaus illusion). RTs were the faster the better test circles could be differentiated from the context circles, ie with smaller numbers of context circles, larger distances, and higher lightness (or colour) contrast between test and context circles. Apparent-size modulation had a strong influence on search RTs, resulting in faster RTs with smaller, and slower RTs with larger, context circles. A model assuming overall facilitatory effects of the apparent-size modulation and interference effects arising from decreasing test-context circle discriminability can explain the present results.     

Auditory temporal information processing in preschool children at family risk for dyslexia: relations with phonological abilities and developing literacy skills

In this project, the hypothesis of an auditory temporal processing deficit in dyslexia was tested by examining auditory processing in relation to phonological skills in two contrasting groups of five-year-old preschool children, a familial high risk and a familial low risk group. Participants were individually matched for gender, age, non-verbal IQ, school environment, and parental educational level. Psychophysical thresholds were estimated for gap-detection, frequency modulation detection, and tone-in-noise detection using a three-interval forced-choice adaptive staircase paradigm embedded within a computer game. Phonological skills were measured by tasks assessing phonological awareness, rapid serial naming, and verbal short-term memory. Significant group differences were found for phonological awareness and letter knowledge. In contrast, none of the auditory tasks differentiated significantly between both groups. However, both frequency modulation and tone-in-noise detection were significantly related to phonological awareness. This relation with phonological skills was not present for gap-detection.     

Cross-cultural generalizability of the youth self-report and teacher's report form cross-informant syndromes

Exploratory factor analyses on 569 Youth Self-Reports and 1,221 Teacher's Report Forms of clinically referred Dutch children revealed six and eight factors respectively, very similar to the eight YSR and TRF cross-informant syndromes derived by Achenbach (1991c, 1991d). Mean cross-cultural correlations were .89 for YSR syndromes and .95 for TRF syndromes. In confirmatory factor analyses of the Dutch and American YSR and TRF factor models in cross-validation samples of 570 YSRs and 1,221 TRFs, goodness-of-fit indices were only slightly better for Dutch factor models. The American cross-informant Social Problems and Attention Problems syndromes had the poorest fit. The application of the eight American cross-informant syndromes to Dutch self-and teacher reports was supported.We wish to thank Dr. Thomas Achenbach for his comments and advice on this article.This research was supported by grants from the Sophia Foundation for Medical Research and from the Dutch National Program for Stimulation of Health Research.     

Models of burnout: Implications for interventions

Three process models of burnout are discussed, Cherniss' process model, Golembiewski's phase model and Leiter's process model. Empirical support for each model is reported. The models make different contributions to the problem of burnout and its development, and the kind of interventions that follow from each model seem to represent different targets. The strengths and weaknesses of the three models are assessed, and the relative merits of individual versus organizational level interventions are addressed. More model-driven research is necessary to reduce the problem of burnout for individuals and organizations.     

A Predictive Approach to Nonparametric Inference for Adaptive Sequential Sampling of Psychophysical Experiments

We present a predictive account on adaptive sequential sampling of stimulus-response relations in psychophysical experiments. Our discussion applies to experimental situations with ordinal stimuli when there is only weak structural knowledge available such that parametric modeling is no option. By introducing a certain form of partial exchangeability, we successively develop a hierarchical Bayesian model based on a mixture of Pólya urn processes. Suitable utility measures permit us to optimize the overall experimental sampling process. We provide several measures that are either based on simple count statistics or more elaborate information theoretic quantities. The actual computation of information theoretic utilities often turns out to be infeasible. This is not the case with our sampling method, which relies on an efficient algorithm to compute exact solutions of our posterior predictions and utility measures. Finally, we demonstrate the advantages of our framework on a hypothetical sampling problem.     

Prosocial norm violations fuel power affordance

The question of what makes people rise to power has long puzzled social scientists. Here we examined the novel hypothesis that power is afforded to individuals who exhibit prosocial norm violations—i.e., breaking rules for the benefit of others. Three experiments using different methods provide support for this idea. Individuals who deliberately ignored a prohibition to tilt a bus chair (Study 1; scenario) or to close a window (Study 2; film clip) were afforded more power than individuals who obeyed the rules, but only when the norm violation benefited others (i.e., by giving them more leg space or fresh air). Study 2 further showed that this effect was mediated by perceived social engagement, which was highest among prosocial norm violators. In Study 3 (face-to-face), a confederate who stole coffee from the experimenter's desk was afforded more power than a confederate who took coffee upon invitation, but only when he also offered coffee to the participant. We discuss implications for hierarchy formation, morality, and social engagement.     

Impulse control disorders in obese patients

The aim of this study was to determine the prevalence of impulse control disorders (ICDs) in morbidly obese individuals. One hundred bariatric surgery candidates were examined using a module of the Structured Clinical Interview for DSM-IV that has been developed for ICDs. Nineteen per cent suffered from at least one current ICD and 27% met the criteria for any lifetime ICD, most frequently skin picking (current, 8%; lifetime, 9%), compulsive buying (current 6%, lifetime 8%), and intermittent explosive disorder (current, 5%; lifetime, 10%). Patients with regular binge eating (N?=?25) reported significantly more often a history of at least one ICD compared with those without binge eating. The results indicate a high prevalence of ICDs among morbidly obese prebariatric surgery patients that are related to regular binge eating.     

Maltreated Children's Memory of Stressful Removals from Their Biological Parents

The effects of stress on memory were examined through a study of 33 3 to 12‐year‐old maltreated children removed from their biological parents by the Child Protective Services because of an emergency (acute) or normal (planned) care order. Children's stress levels were rated by a researcher present during the removal and children's memory of the removal investigated at a later time. The type of removal significantly predicted children's level of stress. ‘Acute removal’ children remembered more from high‐stress phases of the removal than the ‘planned removal’ children. All children had more accurate memories of the low‐stress phases. Details remembered were rated as central or peripheral; more central information was recalled than peripheral information. The ‘acute removal’ children recalled more peripheral information from the high‐stress phases of the removal than the low‐stress phases, a difference, which was not present for the ‘planned removal’ children. Copyright © 2011 John Wiley & Sons, Ltd.