Sex categorization of faces: The effects of age and experience

The face own-age bias effect refers to the better ability to recognize the face from one's own age compared with other age groups. Here we examined whether an own-age advantage occurs for faces sex categorization. We examined 7- and 9-year-olds' and adults' ability to correctly categorize the sex of 7- and 9-year-olds and adult faces without external cues, such as hair. Results indicated that all ages easily classify the sex of adult faces. They succeeded in classifying the sex of child faces, but their performance was poorer than for adult faces. In adults, processing time increased, and a response bias (male response) was elicited for child faces. In children, response times remained constant, and no bias was observed. Experience with specific category of faces seems to offer some advantage in speed of processing. Overall, sex categorization is more challenging for child than for adult faces due to their reduced sexual dimorphic facial characteristics

Long Lasting Egocentric Disorientation Induced by Normal Sensori-Motor Spatial Interaction

Perception of the cardinal directions of the body, right-left, up-down, ahead-behind, which appears so absolute and fundamental to the organisation of behaviour can in fact, be modified. Perhaps unsurprisingly, it has been shown that prolonged distorted perception of the orientation of body axes can be a consequence of disordered sensori-motor signals, including long-term prismatic adaptation and lesions of the central nervous system. We report the novel and surprising finding that a long-lasting distortion of perception of personal space can also be induced by an ecological pointing task without the artifice of distorting normal sensori-motor relationships.Twelve right-handed healthy adults performed the task of pointing with their arms, without vision, to indicate their subjective 'straight ahead', a task often used to assess the Egocentric Reference. This was performed before, immediately, and one day after a second task intended to 'modulate' perception of spatial direction. The 'modulating' task lasted 5 minutes and consisted of asking participants to point with the right finger to targets that appeared only in one (right or left) half of a computer screen. Estimates of the 'straight-ahead' during pre-test were accurate (inferior to 0.3 degrees deviation). Significantly, up to one day after performing the modulating task, the subjective 'straight-ahead' was deviated (by approximately 3.2 degrees) to the same side to which subjects had pointed to targets.These results reveal that the perception of directional axes for behaviour is readily influenced by interactions with the environment that involve no artificial distortion of normal sensori-motor-spatial relationships and does not necessarily conform to the cardinal directions as defined by the anatomy of orthostatic posture. We thus suggest that perceived space is a dynamic construction directly dependent upon our past experience about the direction and/or the localisation of our sensori-motor spatial interaction with environment

Research Proposal Bruel Léa

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Flexibility of the cognitive system to use various spatial coding : Implication for driving situation

International audienc

Asymétrie et plasticité de la perception spaciale (étude de l'adulte sain et cérébro-lésé)

GRENOBLE2/3-BU Droit/Lettres (384212101) / SudocSudocFranceF

Spatial bias induced by a non-conflictual task reveals the nature of space perception

The aim of the present study was to show that space perception depends on sensori-motor experience. We induced spatial biases by a non-conflictual lateralized sensori-motor task on twenty seven right-handed healthy volunteers (left-to-right readers). After a pre-test and before a post-test, which assessed visuo-motor and perceptual subjective midpoint in line bisection, participants performed a short lateralized pointing task (towards the left or right hemispace). Results indicated that this lateralized pointing task induced deviations towards the stimulated hemispace in both the visuo-motor and the perceptual estimations of the subjective line centre. These spatial biases varied as a function of pointing direction (left or right pointing), spatial location and line lengths. These findings suggest that a preceding non-conflictual lateralized sensori-motor experience influences subsequent space perception. Accordingly, ecological sensori-motor experience could be involved in asymmetric perception exhibited by normal individuals and neglect patients

Experimental remission of unilateral spatial neglect

Over the past several decades a growing amount of research has focused on the possibility of transiently reducing left neglect signs in right brain-damaged patients by using vestibular and/or visuo-proprioceptive stimulations. Here we review seminal papers dealing with these visuo-vestibulo-proprioceptive stimulations in normal controls, right brain-damaged (RBD) patients, and animals. We discuss these data in terms of clinical implications but also with regards to theoretical frameworks commonly used to explain the unilateral neglect syndrome. We undermine the effect of these stimulations on the position of the egocentric reference and extend the notion that the positive effects of these stimulation techniques may stem from a reorientation of attention towards the neglected side of space or from a recalibration of sensori-motor correlations. We conclude this review with discussing the possible interaction between experimental rehabilitation, models of neglect and basic spatial cognition research

Induction of lateralized spatial bias among normal subjects

International audienc

What is the relation between unilateral spatial neglect and verticality perception biases after stroke?

International audienceObjectiveUnilateral spatial neglect (USN) and verticality perception biases are frequently associated after right hemispheric cerebral stroke (Pérennou et al., 2006). These troubles in spatial cognition have also in common to present different clinical types, according to the space considered: personal (PN) and extra-personal neglect (EPN), and biases in the visual (VV) or the postural (PV) vertical. Here, we hypothesized that PN is specially related to a biased PV, and that EPN could be more related to a biased VV.Material/Patients and methodsForty-six patients (25 females, 41 right-handed, mean age = 62) were submitted to neuropsychological and verticality perception assessment at 30, 60, and/or 90 days after a first right hemispheric stroke. Z-scores on neuropsychological tests were used to compute a composite score for PN (based on Bisiach test, thumb find test, Comb test, Fluff test and 4 items of the Catherine Bergego Scale, CBS) and EPN (based on bells cancellation test, clock drawing test, overlapping figures task, copy of a landscape, text reading, and 4 items of the CBS). A diagnosis of PN or EPN required at least two abnormal tests. Verticality assessment comprised both VV and PV, considered abnormal for a contralesional bias over 2.5°. We tested the link between neglect and verticality perception by conducting linear regression analyses, on NC and NEC, with VV and PV as predictors.ResultsPN and EPN were found in 28 and 32 patients, respectively. A biased verticality perception was found in 24 patients for VV; among them, 5 without NSU, 12 had PN + EPN, 1 PN, 6 EPN and in 17 patients for PV; among them, 1 without NSU, 13 PN + EPN, 3 EPN. Regression analyses showed that PV was significantly associated to PN (F = 15.4; P < 0.001) but also to EPN (F = 9.4; P < 0.01). No significant effect was found for VV.Discussion - ConclusionFindings confirm the link between neglect and verticality perception. However, instead of showing specific links VV-EPN and VP-PN, results showed that both EPN and PN severity predict a biased PV (but not a biased VV). The stronger links was found between PV and PN, in relation with the body space

Multimodal virtual reality application for the study of unilateral spatial neglect

In the present paper, we describe a virtual reality application developed for the study of unilateral spatial neglect, a post-stroke neurological disorder that results in failure to respond to stimuli presented contralaterally to the damaged hemisphere. Recently, it has been proposed that patients with unilateral spatial neglect experience sensorimotor decorrelation in the affected space. Consequently, it is possible that since the sensorimotor experience in the affected space is perturbed, patients avoid this space, which results in neglect behavior. Here, we evaluate this hypothesis using a virtual reality application built on the base of the Stringed Haptic Workbench, a large-scale visuo-haptic system. The results provide support for the hypothesis and demonstrate that the proposed application is suitable for the envisioned goal