‘Pushing Through’ in Plato’s Sophist: A New Reading of the Parity Assumption

At a crucial juncture in Plato’s Sophist, when the interlocutors have reached their deepest confusion about being and not-being, the Eleatic Visitor proclaims that there is yet hope. Insofar as they clarify one, he maintains, they will equally clarify the other. But what justifies the Visitor’s seemingly oracular prediction? A new interpretation explains how the Visitor’s hope is in fact warranted by the peculiar aporia they find themselves in. The passage describes a broader pattern of ‘exploring both sides’ that lends insight into Plato’s aporetic method

Cynophobic Fear Adaptively Extends Peri-Personal Space

cote interne IRCAM: Taffou14aInternational audiencePeri-personal space (PPS) is defined as the space immediately surrounding our bodies, which is critical in the adaptation of our social behavior. As a space of interaction with the external world, PPS is involved in the control of motor action as well as in the protection of the body. The boundaries of this PPS are known to be flexible but so far, little is known about how PPS boundaries are influenced by unreasonable fear. We hypothesized that unreasonable fear extends the neural representation of the multisensory space immediately surrounding the body in the presence of a feared object, with the aim of expanding the space of protection around the body.To test this hypothesis, we explored the impact of unreasonable fear on the size of PPS in two groups of non-clinical participants: dog-fearful and non-fearful participants. The sensitivity to cynophobia was assessed with a questionnaire. We measured participants’ PPS extent in the presence of threatening (dog growling) and non-threatening (sheep bleating) auditory stimuli. The sound stimuli were processed through binaural rendering so that the virtual sound sources were looming toward participants from their rear hemi-field.We found that, when in the presence of the auditory dog stimulus, the PPS of dog-fearful participants is larger than that of non-fearful participants. Our results demonstrate that PPS size is adaptively modulated by cynophobia and suggest that anxiety tailors PPS boundaries when exposed to fear-relevant features. Anxiety, with the exception of social phobia, has rarely been studied as a disorder of social interaction. These findings could help develop new treatment strategies for anxious disorders by involving the link between space and interpersonal interaction in the approach of the disorder

Auditory-Visual Aversive Stimuli Modulate the Conscious Experience of Fear

International audiencevision. However, the impact of multisensory information on affect remains relatively undiscovered. In this study, we investigated whether the auditory-visual presentation of aversive stimuli influences the experience of fear. We used the advantages of virtual reality to manipulate multisensory presentation and to display potentially fearful dog stimuli embedded in a natural context. We manipulated the affective reactions evoked by the dog stimuli by recruiting two groups of participants: dog-fearful and non-fearful participants. The sensitivity to dog fear was assessed psychometrically by a questionnaire and also at behavioral and subjective levels using a Behavioral Avoidance Test (BAT). Participants navigated in virtual environments, in which they encountered virtual dog stimuli presented through the auditory channel, the visual channel or both. They were asked to report their fear using Subjective Units of Distress. We compared the fear for unimodal (visual or auditory) and bimodal (auditory- visual) dog stimuli. Dog-fearful participants as well as non-fearful participants reported more fear in response to bimodal audiovisual compared to unimodal presentation of dog stimuli. These results suggest that fear is more intense when the affective information is processed via multiple sensory pathways, which might be due to a cross-modal potentiation. Our findings have implications for the field of virtual reality-based therapy of phobias. Therapies could be refined and improved by implicating and manipulating the multisensory presentation of the feared situations

Auditory-visual virtual environment for the treatment of fear of crowds

ABSTRACT Fear of crowds is a symptom found in agoraphobia (among others) and which has both visual and auditory relevant components. In order to examine the potential interest of auditory-visual virtual reality to treat fear of crowds, we investigated the efficiency of an auditory-visual virtual environment in evoking affective reaction. We conducted an evaluation test with healthy participants sensitive to the fear of crowds to explore the influence of auditory-visual virtual environment on affective reactions. Our application involves both high fidelity visual stimulation and interactive 3D sound. Our specific presentation of animated crowds of humans creates an environment that is highly arousing, suggesting that manipulating the sensory presentation together with the spatial location of stimulation might provide a way to modulate affective reactions

Induire un ressenti de peur avec la réalité virtuelle : étude de l'influence de stimuli multisensoriels sur l'expérience émotionnelle négative

In a natural environment, affective events often convey emotional cues through multiple sensory modalities. Yet, the effect of multisensory affective events on the conscious emotional experience (feelings) they induce remains relatively undiscovered. The present research exploited the unique advantages of virtual reality techniques to examine the negative emotional experience induced by auditory-visual aversive events embedded in a natural context. In natural contexts, the spatial distance between the perceiver and the affective stimuli is an important factor. Consequently, this research investigated the relationship between affect, multisensory presentation and space. A first study using virtual reality tested the influence of auditory-visual aversive stimuli on negative emotional experience. A second study explored the effect of excessive fear on the representation of close space. A third study examined the effect of auditory-visual stimuli on negative emotional experience as a function of their location at close or far distances from the perceiver. Overall, it was found that negative emotional experience is modulated by the sensory and spatial characteristics of aversive events. Multisensory aversive events amplify negative feelings only when they are located at close distances from the perceiver. Moreover, excessive fear related to an event extends the space, wherein the event is represented as close. Taken together, the present research provides new information about affective processing and exposes virtual reality as a relevant tool for the study of human affect.Dans l'environnement naturel, les signaux émotionnels sont transmis via différentes modalités sensorielles. Pourtant, l'effet d'évènements affectifs multisensoriels sur l'expérience émotionnelle consciente (le ressenti) reste relativement peu connu. Ce travail de recherche a exploité les avantages de la réalité virtuelle pour étudier le ressenti négatif induit par des évènements aversifs visuo-auditifs présentés dans un contexte écologique. Un tel contexte permet de prendre en compte un facteur important qui est la distance entre le sujet et le stimulus affectif. Par conséquent, ce travail a impliqué l'étude des liens entre l'affect, la présentation multisensorielle et l'espace. Une première étude a exploré l'influence de stimuli aversifs visuo-auditifs sur le ressenti. Une deuxième étude a examiné l'effet de la peur excessive sur la représentation de l'espace péri-personnel. Une troisième étude a testé l'effet de stimuli aversifs visuo-auditifs sur le ressenti en fonction de leur position plus ou moins proche du sujet. En conclusion, il a été constaté que le ressenti émotionnel est modulé par les caractéristiques sensorielles et spatiales des évènements aversifs. Les stimuli aversifs visuo-auditifs amplifient le ressenti négatif. Cependant, cet effet n'existe que si ces stimuli sont dans l'espace proche du sujet. Enfin, la peur excessive d'un stimulus spécifique provoque une extension de l'espace péri-personnel. L'ensemble de ces travaux fournit de nouvelles informations sur le traitement de l'information affective et met en évidence l'utilité et la pertinence de la réalité virtuelle pour l'étude de l'affect

Fear adaptively extends peri-personal space

cote interne IRCAM: Taffou14dNone / NoneNational audienceFear adaptively extends peri-personal spac

Social impact on audiotactile integration near the body

International audienc

Auditory Sketches: Very Sparse Representations of Sounds Are Still Recognizable

International audienceSounds in our environment like voices, animal calls or musical instruments are easily recognized by human listeners. Understanding the key features underlying this robust sound recognition is an important question in auditory science. Here, we studied the recognition by human listeners of new classes of sounds: acoustic and auditory sketches, sounds that are severely impoverished but still recognizable. Starting from a time-frequency representation, a sketch is obtained by keeping only sparse elements of the original signal, here, by means of a simple peak-picking algorithm. Two time-frequency representations were compared: a biologically grounded one, the auditory spectrogram, which simulates peripheral auditory filtering, and a simple acoustic spectrogram, based on a Fourier transform. Three degrees of sparsity were also investigated. Listeners were asked to recognize the category to which a sketch sound belongs: singing voices, bird calls, musical instruments, and vehicle engine noises. Results showed that, with the exception of voice sounds, very sparse representations of sounds (10 features, or energy peaks, per second) could be recognized above chance. No clear differences could be observed between the acoustic and the auditory sketches. For the voice sounds, however, a completely different pattern of results emerged, with at-chance or even below-chance recognition performances, suggesting that the important features of the voice, whatever they are, were removed by the sketch process. Overall, these perceptual results were well correlated with a model of auditory distances, based on spectro-temporal excitation patterns (STEPs). This study confirms the potential of these new classes of sounds, acoustic and auditory sketches, to study sound recognition

Capturing the dynamics of peripersonal space by integrating expectancy effects and sound propagation properties

International audienceBackground. Humans perceive near space and far space differently. Peripersonal space (PPS), i.e. the space directly surrounding the body, is often studied using paradigms based on auditory-tactile integration. In these paradigms, reaction time (RT) to a tactile stimulus is measured in the presence of a concurrent auditory looming stimulus. New Method.We propose here to refine the experimental procedure by disentangling behavioral contributions of the targeted audiotactile integration mechanisms from expectancy effects. To this aim, we added to the protocol a baseline with a fixed sound distance. Furthermore, in order to improve the relevance of the auditory-tactile integration measures, we took into account sound propagation properties and assessed RTs for logarithmically spaced auditory distances. Results. Expectation contributed significantly to overall behavioral responses. Subtracting it isolated the audiotactile effect due to the stimulus proximity. This revealed that audiotactile integration effects have to be tested on a logarithmic scale of distances, and that they follow a linear variation on this scale. Comparison with Existing Method(s). The current method allows cleaner and more pertinent sampling measures for evaluating audiotactile integration phenomena linked to PPS. Furthermore, most of the existing methods propose a sigmoid fitting, which rests on the intuitive framework that PPS is an in-or-out zone. Our results suggest that behavioral effects follow a logarithmic decrease, thus a response graduated in space. Conclusions.The proposed protocol design and method of analysis contribute to sharpen the experimental investigation of the factors influencing and modifying multisensory integration phenomena in the space surrounding the body