Haptic curvature comparison of convex and concave shapes

A sculpture and the mould in which it was formed are typical examples of objects with an identical, but opponent, surface shape: each convex (ie outward pointing) surface part of a sculpture has a concave counterpart in the mould. The question arises whether the object features of opponent shapes can be compared by touch. Therefore, we investigated whether human observers were able to discriminate the curvatures of convex and concave shapes, irrespective of whether the shape was convex or concave. Using a 2AFC procedure, subjects had to compare the curvature of a convex shape to the curvature of a concave shape. In addition, results were also obtained for congruent shapes, when the curvature of either only convex shapes or only concave shapes had to be compared. Psychometric curves were fitted to the data to obtain threshold and bias results. When subjects explored the stimuli with a single index finger, significantly higher thresholds were obtained for the opponent shapes than for the congruent shapes. However, when the stimuli were touched by two index fingers, one finger per surface, we found similar thresholds. Systematic biases were found when the curvature of opponent shapes was compared: the curvature of a more curved convex surface was judged equal to the curvature of a less curved concave surface. We conclude that human observers had the ability to compare the curvature of shapes with an opposite direction, but that their performance decreased when they sensed the opponent surfaces with the same finger. Moreover, they systematically underestimated the curvature of convex shapes compared to the curvature of concave shapes.     

How age affects memory task performance in clinically normal hearing persons

The main objective of this study is to investigate memory task performance in different age groups, irrespective of hearing status. Data are collected on a short-term memory task (WAIS-III Digit Span forward) and two working memory tasks (WAIS-III Digit Span backward and the Reading Span Test). The tasks are administered to young (20–30 years, n = 56), middle-aged (50–60 years, n = 47), and older participants (70–80 years, n = 16) with normal hearing thresholds. All participants have passed a cognitive screening task (Montreal Cognitive Assessment (MoCA)). Young participants perform significantly better than middle-aged participants, while middle-aged and older participants perform similarly on the three memory tasks. Our data show that older clinically normal hearing persons perform equally well on the memory tasks as middle-aged persons. However, even under optimal conditions of preserved sensory processing, changes in memory performance occur. Based on our data, these changes set in before middle age.     

Replications and extensions in arousal assessment for sex offenders with developmental disabilities

Three adult male sex offenders with developmental disabilities participated in phallometric assessments that involved repeated measures of arousal when exposed to various stimuli. Arousal assessment outcomes were similar to those obtained by Reyes et al. (2006). Additional data-analysis methods provided further information about sexual preferences, thus replicating and extending previous research. The results provide preliminary data for establishing a preference gradient by age. Implications for the use of repeated measures and preference gradients in arousal assessments are discussed.     

A cross-cultural study of relationships between daily social interaction and the five-factor model of personality

Two studies, one in the United States (N = 130) and another in Germany (N = 100), examined relationships between daily social interaction and the traits of the Five-Factor Model. In both studies, student participants described their social interactions for 2 weeks using the Rochester Interaction Record. In both countries, Agreeableness and Conscientiousness were positively related to reactions to social interaction, whereas Neuroticism was unrelated to reactions to interactions. In the United States, Extraversion and Openness were positively related to reactions to interactions, whereas these factors were not related to reactions to interactions in Germany. In the United States, Extraversion was positively related to how socially active participants were, whereas none of the FFM traits was related to amount of social interaction in the German sample. In both countries, Extraversion was positively related to percent of interactions involving friends. The results highlight the importance of taking into account the sociocultural milieus within which personality unfolds.     

Matters of Interest: The Objects of Research in Science and Technoscience

This discussion paper proposes that a meaningful distinction between science and technoscience can be found at the level of the objects of research. Both notions intermingle in the attitudes, intentions, programs and projects of researchers and research institutions—that is, on the side of the subjects of research. But the difference between science and technoscience becomes more explicit when research results are presented in particular settings and when the objects of research are exhibited for the specific interest they hold. When an experiment is presented as scientific evidence which confirms or disconfirms a hypothesis, this agrees with traditional conceptions of science. When organic molecules are presented for their capacity to serve individually as electric wires that carry surprisingly large currents, this would be a hallmark of technoscience. Accordingly, we propose research on the ontology of research objects. The focus on the character and significance of research objects makes this a specifically philosophical project.     

Revisiting the African origins of attachment research—50 years on from Ainsworth: A descriptive review

Culture plays a significant role in the variations observed in the manifestation, expression, and meaning of attachment behaviors. Africa is home to multiple cultures, with distinct organizations of caregiving relationships underlying the development of attachment. This review aims to consolidate knowledge about African attachment by describing studies of infant attachment conducted in Africa since Mary Ainsworth's Ugandan findings in 1967. Electronic databases were searched with the terms “Africa” (“attachment” or “bond”) and “infant.” Nine studies that assessed infant attachment style with self-report or observation methods were included, but spanned only five countries. The Strange Situation Procedure was most frequently used. Most studies described dyads living in peri-urban or township areas. Multiple socioeconomic factors affecting living conditions were identified, including, unemployment, financial difficulties, limited education, poor housing, single parenthood, lack of partner support, substance abuse, and depression. Overall distributions of attachment classification proportions appear consistent with global attachment-classification patterns. Despite adverse conditions, secure attachment was relatively widespread, and some populations had low rates of avoidant attachment. Relatively high rates of disorganized attachment were found when the category was included. Africa remains an understudied continent regarding infant attachment. The continent's cultural diversity may hold important truths necessary for understanding the complex relationship between infant and attachment figure.     

A single exposure to severe stressors causes long-term desensitisation of the physiological response to the homotypic stressor

Although some laboratories have reported that a single session of stress is able to induce a long-lasting sensitisation of the hypothalamic-pituitary-adrenal (HPA) response to further exposures to stress, we have found that a single exposure to severe emotional (immobilisation, restraint or shock) or systemic (endotoxin) stressors reduces the responsiveness of the HPA to the same, but not to a novel (heterotypic), stressor, in which case a slight sensitisation was observed. Long-term desensitisation has been found to reduce not only secretion of peripheral HPA hormones (ACTH and corticosterone), but also to reduce responses of central components of the HPA axis (c-fos and CRF gene expression at the level of the paraventricular nucleus of the hypothalamus, PVN). In addition, desensitisation also applies to the impact of the stressor on food intake and, probably, to stress-induced hyperglycaemia. The development of long-term desensitisation of the HPA axis does not appear to be a universal consequence of exposure to severe stressors as it was not observed in response to insulin-induced hypoglycaemia. Whether or not the development of long-term effects of stress depend on the specific pathways activated by particular stressors remains to be tested. The observed desensitisation of the HPA axis in response to the homotypic stressor shows two special features which makes it difficult to be interpreted in terms of an habituation-like process: (a) the effect increased with time (days to weeks) elapsed between the first and second exposure to the stressor, suggesting a progressive maturational process; and (b) the stronger the stressor the greater the long-term desensitisation. Therefore, it is possible that desensitisation of the HPA axis is the sum of two different phenomena: long-term effects and habituation-like processes. The contribution of the former may be more relevant with severe stressors and longer inter-stress intervals, and that of the latter with mild stressors and repeated exposures. Long-term stress-induced changes may not take place at the level of the PVN itself, but in brain nuclei showing synaptic plasticity and putatively involved in the control of the HPA axis and other physiological responses. As for the precise areas involved, these remain to be characterized.     

Pappus in optical space

Optical space differs from physical space. The structure of optical space has generally been assumed to be metrical. In contradistinction, we do not assume any metric, but only incidence relations (i.e., we assume that optical points and lines exist and that two points define a unique line, and two lines a unique point). (The incidence relations have generally been assumed implicitly by earlier authors.) The condition that makes such an incidence structure into a projective space is the Pappus condition. The Pappus condition describes a projective relation between three collinear triples of points, whose validity can--in principle--be verified empirically. The Pappus condition is a necessary condition for optical space to be a homogeneous space (Lobatchevski hyperbolic or Riemann elliptic space) as assumed by, for example, the well-known Luneburg theory. We test the Pappus condition in a full-cue situation (open field, broad daylight, distances of up to 20 m, visual fields of up to 160 degrees diameter). We found that although optical space is definitely not veridical, even under full-cue conditions, violations of the Pappus condition are the exception. Apparently optical space is not totally different from a homogeneous space, although it is in no way close to Euclidean.