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Cross-cutting Challenges - Theme 2: Interactive Discussions
Cross-cutting Challenges
California East
Tactile Perceptual Effects Specifically Relating to Surfaces
Vincent Hayward
(University of London, UK; Actronika SAS, France)
Abstract: The presentation will cover three studies relating to surfaces. In the first we hold the unconventional view that, when we are in contact with surfaces, touch informs proprioception rather than the conventionally adopted opposite view. The case in point is the perceptual task of deciding whether an object is stationary or is moveable. This task is an example of the general perceptual problem that is faced by any organism to relate internal and external sensory information to explain a stimulus. In touch, a frequent occurrence, not shared by vision, is the modification of the state of objects by manipulation through pushing, squeezing, etc. In 'The Brain Uses Extra-Somatic Information To Estimate Limb Displacement' by Terekhov and Hayward, 2015, we show through a proprioceptive illusion induced by tactile inputs that the brain uses the prior knowledge of the mechanical properties of touched surfaces to estimate the state of the body. In 'Looking for Physical Invariants in the Mechanical Response of a Tactually Scanned Braille Dot' by Bochereau, Sinclair, and Hayward, 2015, we found that our perceptual system does not encode the intensity and the duration of brief tactile events independently, not any more than in other sensory modalities. The implications of this finding — which relates to how we sense asperities and coarse textures — will be discussed in terms of early touch since we have collected recent evidence that this tradeoff is already encoded in the spiking characteristics of peripheral afferents. The third study “Touch uses frictional cues to discriminate flat materials” by Gueorguiev, Bochereau, et al., 2016 shows that the material of optically smooth surfaces can be discriminated by touch and that the sense of touch is sensitive to materials probably through differences in hydrophobicity.

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Time stamp: 2019-05-19T18:52:02+02:00