Narrowing in categorical responding to other‐race face classes by infants

Infants can form object categories based on perceptual cues, but their ability to form categories based on differential experience is less clear. Here we examined whether infants filter through perceptual differences among faces from different other‐race classes and represent them as a single other‐race class different only from own‐race faces. We used a familiarization/novelty‐preference procedure to investigate category formation for two other‐race face classes (Black vs. Asian) by White 6‐ and 9‐month‐olds. The data indicated that while White 6‐month‐olds categorically represented the distinction between Black and Asian faces, White 9‐month‐olds formed a broad other‐race category inclusive of Black and Asian faces, but exclusive of own‐race White faces. The findings provide evidence that narrowing can occur for mental processes other than discrimination: category formation is also affected. The results suggest that frequency of experience with own‐race versus other‐race classes of faces may propel infants to contrast own‐race faces with other‐race faces, but not different classes of other‐race faces with each other.     

Multisensory integration in multiple reference frames in the posterior parietal cortex

Spatial information processing takes place in different brain regions that receive converging inputs from several sensory modalities. Because of our own movements—for example, changes in eye position, head rotations, and so forth—unimodal sensory representations move continuously relative to one another. It is generally assumed that for multisensory integration to be an orderly process, it should take place between stimuli at congruent spatial locations. In the monkey posterior parietal cortex, the ventral intraparietal (VIP) area is specialized for the analysis of movement information using visual, somatosensory, vestibular, and auditory signals. Focusing on the visual and tactile modalities, we found that in area VIP, like in the superior colliculus, multisensory signals interact at the single neuron level, suggesting that this area participates in multisensory integration. Curiously, VIP does not use a single, invariant coordinate system to encode locations within and across sensory modalities. Visual stimuli can be encoded with respect to the eye, the head, or halfway between the two reference frames, whereas tactile stimuli seem to be prevalently encoded relative to the body. Hence, while some multisensory neurons in VIP could encode spatially congruent tactile and visual stimuli independently of current posture, in other neurons this would not be the case. Future work will need to evaluate the implications of these observations for theories of optimal multisensory integration.Edited by: Marie-Hélène Giard and Mark Wallace     

Place and Displacement: Towards a Distopological Approach

Most recently, debates on decolonization, transformation, and Africanization raise, again, critical questions about the continuous dominance of the Western practice of philosophy in an African place. Such debates bear particular reference to colonization; however, they are relevant to any place where displacement is an issue and transformation demanded. Yet, the concept of displacement receives surprisingly little attention in these debates or in literature on place. I argue that place and displacement are inherently related, and explore some implications of this relation with regard to the practice of philosophy. My contention is that while displacement is an issue that raises specific challenges to the practice of Western philosophy in an African context, it is in fact a defining feature of philosophy as such in search of its place in the world. In conclusion, I propose what I call a distopological approach towards a philosophical practice that takes seriously its place and inherent relation to displacement.     

Brain drain: A communitarian response to Brock and Blake

The problem of brain drain, the movement of skilled citizens of developing countries to developed ones, arises largely because of seriously unequal life prospects in different countries. Hence, there is something profoundly wrong with the brain drain, something that calls for a moral response. Brock and Blake offer such a response by debating the ethical rights and responsibilities of skilled professionals, and of the societies in which they live, from the perspective of moral liberalism. The aim of my paper is to develop a response to some of their arguments from the perspective of moral communitarianism, with particular reference to the work of one of its classical proponents in African philosophy, Kwame Gyekye.     

Authentic leadership influences on organisational commitment in a South African state hospital

This study investigated the influence of authentic leadership (AL) on employee organisational commitment (OC) in a South African state hospital. A convenience sample of 222 employees (female = 81%; black = 82%) completed the Authentic Leadership Questionnaire on their perceptions of AL behaviours among their leaders; namely self-awareness, relational transparency, internalised moral perspective, and balanced processing. The employees also completed the Organisational Commitment Questionnaire to self-report on their own OC; namely affective, continuance, and normative commitment. Data were analysed utilising regression analysis to predict employees’ self-reported OC from perceived AL behaviours. Findings suggest AL scores to predict OC scores as well as the OC dimensions of continuance and normative commitment. AL scores did not predict affective commitment. Employees whose leaders apply AL may be able to retain employees through increased OC.     

Edge detection based on Hodgkin–Huxley neuron model simulation

In this paper, we propose a spiking neural network model for edge detection in images. The proposed model is biologically inspired by the mechanisms employed by natural vision systems, more specifically by the biologically fulfilled function of simple cells of the human primary visual cortex that are selective for orientation. Several aspects are studied in this model according to three characteristics: feedforward spiking neural structure; conductance-based model of the Hodgkin–Huxley neuron and Gabor receptive fields structure. A visualized map is generated using the firing rate of neurons representing the orientation map of the visual cortex area. We have simulated the proposed model on different images. Successful computer simulation results are obtained. For comparison, we have chosen five methods for edge detection. We finally evaluate and compare the performances of our model toward contour detection using a public dataset of natural images with associated contour ground truths. Experimental results show the ability and high performance of the proposed network model.     

Sensory load incurs conceptual processing costs

Theories of grounded cognition propose that modal simulations underlie cognitive representation of concepts [Barsalou, L. W. (1999). Perceptual symbol systems. Behavioral and Brain Sciences, 22(4), 577-660; Barsalou, L. W. (2008). Grounded cognition. Annual Review of Psychology, 59, 617-645]. Based on recent evidence of modality-specific resources in perception, we hypothesized that verifying properties of concepts encoded in different modalities are hindered more by perceptual short-term memory load to the same versus different sensory modality as that used to process the property. We manipulated load to visual and auditory modalities by having participants store one or three items in short-term memory during property verification. In the high (but not low) load condition, property verification took longer when the property (e.g., yellow) involved the same modality as that used by the memory load (e.g., pictures). Interestingly, similar interference effects were obtained on the conceptual verification and on the memory task. These findings provide direct support for the view that conceptual processing relies on simulation in modality-specific systems.     

Aggressor and victim perspective-related differences in perceived legitimacy of aggression in soccer

The purpose of this role-playing study was to explore the perceived legitimacy of aggression in soccer as a function of perspective-related differences (aggressor vs victim) and type of aggression (instrumental vs hostile). 120 soccer players watched videotaped aggressive interactions in soccer and took the perspective of the actors (aggressor then victim or the reverse). Then they rated the legitimacy of each aggressive behavior depending on its ultimate goal (instrumental then hostile or the reverse). When participants adopted the aggressor perspective, they perceived instrumental aggression as more legitimate than hostile aggression. In contrast, when participants took the perspective of the victim, no significant difference was found regardless of the type of aggression. The discussion focussed on implications and consequences of such divergences in aggressive sport situations.     

The modular structure of physical theories

Any advanced theory of physics contains modules defined as essential components that are themselves theories with different domains of application. Different kinds of modules can be distinguished according to the way in which they fit in the symbolic and interpretive apparatus of a theory. The number and kind of the modules of a given theory vary as the theory evolves in time. The relative stability of modules and the variability of their insertion in other theories play a vital role in the application, comparison, construction, and communication of theories. Modularity conveys some global unity to physics through the sharing of modules by diverse theories. This alternative to rigid hierarchies and holistic totalities permits a dynamical, plastic, and symbiotic approach to physical theory.     

Aging of the planning process: the role of executive functioning

This study tested whether the aging of executive functioning is linked to the decline in planning performance. Participants were divided into three groups: group 1 composed of 15 adults with a mean age of 22.7 years, group 2 composed of 15 adults with a mean age of 68.1 years and group 3 composed of 16 adults with a mean age of 78.75 years. Each participant took tests for shifting, inhibition, updating and processing speed. Planning was evaluated by the Tower of Hanoi task with 3 and 4 disks. Analyses of variance showed a main age effect on the many executive functioning and planning measures assessed. Analyses of regression indicated that combined processing speed and shifting accounted for 58.33% of performance on the 3-disk version, while processing speed accounted for only 36.86% of performance on the 4-disk version. These results are discussed in relation to two levels of the planning process: formulation and execution.