Lightness constancy: Ratio invariance and luminance profile

The term simultaneous lightness constancy describes the capacity of the visual system to perceive equal reflecting surfaces as having the same lightness despite lying in different illumination fields. In some cases, however, a lightness constancy failure occurs; that is, equal reflecting surfaces appear different in lightness when differently illuminated. An open question is whether the luminance profile of the illumination edges affects simultaneous lightness constancy even when the ratio invariance property of the illumination edges is preserved. To explore this issue, we ran two experiments by using bipartite illumination displays. Both the luminance profile of an illumination edge and the luminance ratio amplitude between the illumination fields were manipulated. Results revealed that the simultaneous lightness constancy increases when the luminance profile of the illumination edge is gradual (rather than sharp) and homogeneous (rather than inhomogeneous), whereas it decreases when the luminance ratio between the illumination fields is enlarged. The results are interpreted according to the layer decomposition schema, stating that the visual system splits the luminance into perceived lightness and apparent illumination components. We suggest that illumination edges having gradual and homogeneous luminance profiles facilitate the luminance decomposition process, whereas wide luminance ratios impede it.     

Scaffolding knowledge

In this article I argue that often propositional knowledge is acquired and retained by extensive reliance on physical and social scaffolds that create an environment or niche conducive to knowledge. It is incumbent on epistemologists to subject these aids to epistemic assessments. I show that several of the activities involved in the creation of niches within which inquiry can thrive are carried out by whole cultures. New generations benefit from inheriting these niches whilst being able to improve upon them to the advantage of their descendants. Finally, I highlight that the growth of human epistemic achievements is often due to increased outsourcing of cognitive effort and epistemic powers onto impersonal physical and social structures so that human beings can succeed more by contributing less to the solution of problems.     

Na+,K(+)-ATPase activity is reduced in hippocampus of rats submitted to an experimental model of depression: effect of chronic lithium treatment and possible involvement in learning deficits

This study was undertaken to verify the effects of chronic stress and lithium treatments on the hippocampal Na+,K(+)-ATPase activity of rats, as well as to investigate the effects of stress interruption and post-stress lithium treatment on this enzyme activity and on spatial memory. Two experiments were carried out; in the first experiment, adult male Wistar rats were divided into two groups: control and submitted to a chronic variate stress paradigm, and subdivided into treated or not with LiCl. After 40 days of treatment, rats were killed, and Na+,K(+)-ATPase activity was determined. In the second experiment, rats were stressed during 40 days, and their performance was evaluated in the Water Maze task. The stressed group was then subdivided into four groups, with continued or interrupted stress treatment and treated or not with lithium for 30 additional days. After a second evaluation of performance in the Water Maze, rats were killed and Na+,K(+)-ATPase activity was also measured. Results showed an impairment in Na+,K(+)-ATPase activity and in Water Maze performance of chronically stressed rats, which were prevented by lithium treatment and reversed by lithium treatment and by stress interruption. These results suggest that the modulation of Na+,K(+)-ATPase activity may be one of the mechanisms of action of lithium in the treatment of mood disorders.     

Why do women underperform under stereotype threat? Evidence for the role of negative thinking

This study investigated the role of negative thinking as a potential mediator of performance deficits under stereotype threat. After being assigned to a stereotype-threat or a no-threat condition, 60 female participants were asked to complete a difficult math task. Using the thought-listing technique, women under stereotype threat reported a higher number of negative thoughts specifically related to the test and to mathematics compared with women in the no-threat condition. Moreover, women under stereotype threat also showed a sharp decrease in performance that (a) was most pronounced in the second half of the test and (b) was mediated by the increase in negative thinking.     

A data-driven approach to neuropsychological features in isolated REM behaviour disorder: A latent class analysis

Recent evidence demonstrated that neuropsychological assessment may be considered a valid marker of neurodegeneration in idiopathic REM sleep behaviour disorder (iRBD). However, little is known about the possible neuropsychological heterogeneity within the iRBD population. This retrospective study aimed to identify and describe different neuropsychological phenotypes in iRBD patients by means of a data-driven approach using latent class analysis. A total of 289 iRBD patients underwent a neuropsychological assessment evaluating cognitive domains: global cognition, language, short- and long-term memory, executive functions and visuospatial abilities. The presence of mild cognitive impairment (MCI) was also assessed. Latent class analysis was carried out to identify iRBD subtypes according to neuropsychological scores. The most parsimonious model identified three latent classes. Groups were labelled as follows: Class 2 “severely impaired” (n = 83/289): mean pathological scores in different tests, a high percentage of MCI multiple-domain and impairment in all neuropsychological domains. Class 1 “moderately impaired” (n = 44/289): mean neuropsychological score within the normal value, a high percentage of MCI (high risk to phenoconversion) and great impairment in the visuospatial domain. Class 3 “slightly impaired” (n = 162/289): no deficit worthy of attention except for short- and long-term memory. Our results suggest three different clinical phenotypes within the iRBD population. These findings may be relevant in the future for predicting the clinical trajectories of phenoconversion in iRBD.     

Molyneux' question redux

After more than three centuries, Molyneux's question continues to challenge our understanding of cognition and perceptual systems. Locke, the original recipient of the question, approached it as a theoretical exercise relevant to long-standing philosophical issues, such as nativism, the possibility of common sensibles, and the empiricism-rationalism debate. However, philosophers were quick to adopt the experimentalist's stance as soon as they became aware of recoveries from congenital blindness through ophtalmic surgery. Such recoveries were widely reported to support empiricist positions, suggesting that the question had found its empirical answer. Contrary to this common view, we argue that studies of patients recovering from early blindness through surgery cannot provide an answer. In fact, because of the very nature of such ophtalmological interventions it is impossible to test the question in the empirical conditions outlined by Molyneux. Thus we propose that Molyneux's question be treated as an early thought experiment of a specific kind. Although thought experiments of this kind cannot be turned into actual experimental conditions, they provide a conceptual restructuring of theories. Such restructuring in turn leads to new predictions that can then be tested by normal experiments. In accord with this interpretation, we show that Molyneux's question can be analyzed into a hierarchy of specific questions about vision in its phenomenal and sensory-motor components. Some of these questions do lead to actual experimental conditions that could be studied empirically.     

The scholar’s best friend: research trends in dog cognitive and behavioral studies

Animal Cognition - In recent decades, cognitive and behavioral knowledge in dogs seems to have developed considerably, as deduced from the published peer-reviewed articles. However, to date, the...     

Validation of the Duke Religion Index: DUREL (Portuguese Version)

The purpose of the current study was to examine the psychometric properties of the Portuguese version of the Duke Religion Index (PDUREL) in a community setting. PDUREL was translated and adapted for administration to 383 individuals from a population-based study of low-income community-dwelling adults. The PDUREL intrinsic subscale and total scores demonstrated high internal consistency (alphas ranging from 0.733 for the total scale score to 0.758 for the intrinsic subscale). Correlations among the DUREL subscales were also examined for evidence of discriminant validity. Correlations were ranging from 0.36 to 0.46, indicating significant overlap between the scales without marked redundancy. PDUREL is a reliable and valid scale. The availability of a comprehensive, but brief measure of religiousness can help to study the role of religiousness in health by researchers from countries that speak the Portuguese language.     

Childhood conduct problems are associated with increased partnership and parenting difficulties in adulthood

This paper uses data from a sample of 337 parents studied at age 30 to examine the linkages between childhood conduct problems assessed at ages 7–9 and later partnership and parenting outcomes. The key findings of this study were: 1) increasing levels of childhood conduct problems were associated with increased risk of partnership difficulties, including relationship ambiguity, inter-partner conflict/violence and lower levels of relationship satisfaction; 2) increasing levels of childhood conduct problems were associated with increased risk of parenting difficulties, including over-reactivity, lax and inconsistent discipline, child physical punishment and lower levels of parental warmth and sensitivity. These findings were consistent across both parent reports and interviewer ratings, and in nearly all cases remained after extensive adjustment for confounding and selection bias. Study findings add to the growing body of evidence documenting the adverse consequences of early conduct problems for later adult interpersonal relationships and parenting behaviors.