On the adaptive origins and maladaptive consequences of human inbreeding: Parasite prevalence, immune functioning, and consanguineous marriage

We propose that consanguineous marriages arise adaptively in response to high parasite prevalence and function to maintain coadapted gene complexes and associated local adaptation that defend against local pathogens. Therefore, a greater prevalence of inbreeding by consanguineous marriage is expected in geographical regions that historically have had high levels of disease-causing parasites. Eventually such marriages may, under the contemporary high movement of people with modern transportation, jeopardize the immunity of those who practice inbreeding as this leads to an increased susceptibility to novel pathogens. Therefore, a greater frequency of inbreeding is expected to predict higher levels of contemporary mortality and morbidity from infectious diseases. This parasite model of human inbreeding was supported by an analysis involving 72 countries worldwide. We found that historically high levels of pathogen prevalence were related positively to the proportion of consanguineous marriages, and that a higher prevalence of such marriages was associated with higher contemporary mortality and morbidity due to pathogens. Our study addresses plausible alternative explanations. The results suggest that consanguineous marriage is an adaptive consequence of historical pathogen ecologies, but is maladaptive in contemporary disease ecologies.     

When hoarding is a symptom of OCD: A case series and implications for DSM-V

Hoarding, the excessive collection and failure to discard objects of apparently little value, can represent a serious psychiatric problem and pose a threat to public health. Hoarding has traditionally been considered a symptom (or symptom dimension) of Obsessive-Compulsive Disorder (OCD), but its nosological status has recently been debated. Mounting evidence suggests that, once other primary causes are ruled out, hoarding may be a discrete diagnostic entity, recently named Hoarding Disorder. However, hoarding can sometimes be a genuine OCD symptom. This can be confusing and clinicians may sometimes struggle making the differential diagnosis. To illustrate this, we describe 10 OCD patients with severe hoarding behavior that is better conceptualized as a symptom of OCD. We focus on the motivations for hoarding and the overlapping of hoarding with other obsessive-compulsive symptom dimensions. We estimate that this clinical presentation is relatively rare and accounts for a minority of severe hoarding cases. We discuss the unique characteristics of hoarding as a symptom of OCD and the implications for DSM-V.     

Predictors of multitasking performance in a synthetic work paradigm

This study investigated determinants of success in a ‘synthetic work’ task designed to reflect the requirement for multitasking that is common to many occupations. Participants were administered tests of working memory capacity (WMC) and processing speed (PS), and they reported experience with videogames, a type of activity presumed to involve multitasking. Results revealed that WMC was a strong predictor of multitasking in a ‘non‐emergency’ condition when the pace of the tasks was relatively slow, whereas PS was a weaker predictor. Additionally, there was evidence for the incremental validity of videogame experience (VGE), consistent with the possibility that multitasking is supported by a general, trainable skill. Finally, individual differences in strategy use accounted for a large proportion of the variance in multitasking, above and beyond other predictor variables, and WMC predicted use of an effective strategy. Copyright © 2009 John Wiley & Sons, Ltd.     

Educating both halves of the brain: Educational breakthrough or neuromythology?

The increasing popularity of the idea that the two hemispheres of the human cerebral cortex carry on different modes of thinking has resulted in an accelerating social and commercial pressure to organize school curricula, teaching, and testing to conform to a right brain-left brain dichotomy. Evidence gathered from commissurotomy (split-brain) patients and right hemisphere studies on normal intact humans is reviewed and evaluated. Conclusions from this review are (a) the commissurotomy patients are not a suitable group on which to base generalizations about cortical functioning in the normal intact human; (b) the right-left hemisphere differences reported in many experiments on normal subjects are small and can be found only in an extremely narrow experimental context; and (c) there is no scientific basis in this work for any reorganization of curricular, teaching, or testing programs within contemporary educational practice.     

Differential Competencies Contributing to Children's Comprehension of Narrative and Expository Texts

The purpose of this study was to examine the connections between the oral reading abilities and the spelling behaviors of third and fifth grade students. Seventy-two third graders and sixty fifth graders from two different schools (one urban and one suburban) were the subjects of the study. Each subject read a selection one level above his/her current grade placement, spelled the words on the appropriate grade level list of the Qualitative Inventory of Word Knowledge and took the appropriate level of the Gates-MacGinitie Reading Tests. Oral readings were scored for accuracy, rate and phrasing. Spellings were scored for accuracy, phonetic quality and stage of spelling development. These scores were then analyzed using correlations, partial correlations and multiple regression techniques. At both grade levels there were high, significant correlations between spelling and reading variables, with spelling variables accounting for from 40% to 60% of the variance in oral reading measures and a smaller, but still significant percentage of the variance when standardized test scores were used as a control. These results confirm a strong relationship between spelling skill and oral reading ability, supporting the argument that a common body of conceptual word knowledge underlies both.     

Cognitive Vulnerability to Depression in Canadian and Chinese Adolescents

The goal of the current study was to compare diathesis-stress and transactional models of cognitive vulnerability to depression in samples of Canadian (n = 118) and Chinese (n = 405) adolescents. We utilized a six-month multi-wave, longitudinal design in order to examine whether (a) perceived control moderated the association between the occurrence of dependent interpersonal stressors and subsequent increases in depressive symptoms (i.e., a diathesis-stress perspective) and (b) dependent interpersonal stressors mediated the association between perceived control and subsequent increases in depressive symptoms (i.e., a transactional perspective). Results from idiographic, time-lagged, hierarchical linear modeling analyses indicated that for Canadian adolescents both diathesis-stress and transactional models were significant predictors of depressive symptomology. When examining the diathesis-stress model, boys, but not girls, who reported lower perceived control, reported higher levels of depressive symptoms following the occurrence of dependent interpersonal stress. Gender differences, however, were not present in the transactional model. In contrast, transactional, but not diathesis-stress, models were significant in Chinese adolescents, and gender differences did not emerge. Overall, these results may reflect culturally-relevant differences in the etiology of depression in Canadian and Chinese adolescents.     

The interplay of controlled and automatic processing in the expression of spontaneously inferred traits: A PDP analysis

Inferences made about actors influence subsequent processing about those actors. Three experiments conducted in the context of spontaneous trait inference (STI) making demonstrate that such influences occur can either occur via automatic processes or via controlled processes. Results from Experiment 1 demonstrated that processing goals manipulated prior to encoding actor behavior affected the extent to which STIs automatically influenced subsequent responses but did not alter the extent to which STIs influenced those responses via controlled processes. Results from Experiment 2 showed that the extent to which STIs affected subsequent responding via the action of controlled processes were more affected by a delay between exposure to an actor behavior and the response task than the extent to which STIs affected task performance via the action of automatic processes. Finally, results from Experiment 3 showed that participants' subjective experience of awareness of their trait inferences is related to estimates of the extent to which controlled processing is involved in the production of their future responses but not to estimates of the extent to which those responses are affected by automatic processing.     

Quantifying Idiodynamics: A Process Approach to Personality Psychology

Rosenzweig's (1950) concept of idiodynamics is presented, and the importance of time in applied idiodynamics is stressed. Time-series analyses are proposed as one method for realizing the potential of idiodynamics for understanding and modeling individual lives. Building on this, and incorporating Cattell's (1966) notion of the data box, a process approach to personality research is proposed. This approach begins with idiodynamic analyses at the level of individual lives in an effort to identify patterns or themes, then proceeds to examine individual differences in the patterns or themes so identified. Examples of applying this process approach to personality questions are provided. These include identification of cycles in daily moods, assessing the link between each individual's moods and the events in his/her daily life, and the relation between repressive coping style and the experience of and memory for affect-charged life events. Conclusions emphasize how this approach can retain the appeal of the dynamic while maintaining the precision and rule-governed discourse afforded by quantification.     

Human (Homo sapiens) facial attractiveness in relation to skin texture and color

The notion that surface texture may provide important information about the geometry of visible surfaces has attracted considerable attention for a long time. The present study shows that skin texture plays a significant role in the judgment of female facial beauty. Following research in clinical dermatology, the authors developed a computer program that implemented an algorithm based on co-occurrence matrices for the analysis of facial skin texture. Homogeneity and contrast features as well as color parameters were extracted out of stimulus faces. Attractiveness ratings of the images made by male participants relate positively to parameters of skin homogeneity. The authors propose that skin texture is a cue to fertility and health. In contrast to some previous studies, the authors found that dark skin, not light skin, was rated as most attractive.     

Factors in athletic achievement: reply to Van Rossum (2004)

Several lines of evidence have questioned the contribution of innate talents to achievement. Nonetheless, it is also apparent that belief in talent is still common and affects perceptions that athletes form about themselves and fellow competitors about different levels of achievement.