Integration of haptics and vision in human multisensory grasping

Abstract

Grasping actions are directed not only toward objects we see but also toward objects we both see and touch (multisensory grasping). In this latter case, the integration of visual and haptic inputs improves movement performance compared to each sense alone. This performance advantage could be due to the integration of all the redundant positional and size cues or to the integration of only a subset of these cues. Here we selectively provided specific cues to tease apart how these different sensory sources contribute to visuo-haptic multisensory grasping. We demonstrate that the availability of the haptic positional cue together with the visual cues is sufficient to achieve the same grasping performance as when all cues are available. These findings provide strong evidence that the human sensorimotor system relies on non-visual sensory inputs and open new perspectives on their role in supporting vision during both development and adulthood.

Visual uncertainty unveils the distinct role of haptic cues in multisensory grasping

“…A tendency of observing a credibly smaller peak grip aperture in VH compared to V condition was also observed. These results replicate our previous findings and further corroborate that the simultaneous availability of visual and haptic inputs leads to a multisensory advantage (Camponogara & Volcic, 2019b, 2021b).…”

“…The scaling was equivalent in the VH and V conditions, and stronger compared to the H condition (Figure 4D). This can be considered as a sign that, in central vision, the peak grip aperture modulation in multisensory grasping is mainly based on the visual size cue, as suggested by our previous study (Camponogara & Volcic, 2021b).…”

“…The integration of these redundant sensory cues fosters a consistently superior grasping performance compared to when movements are guided by each modality alone (Camponogara & Volcic, 2019a, 2019b). Even more intriguingly, the same superior grasping performance is achieved when the haptic size cue is not provided and vision is complemented by only the haptic position cue (Camponogara & Volcic, 2021b).…”

“…The superior performance in multisensory grasping might arise from the visual and haptic integration at the level of the position cues only which would reduce the uncertainty about the position of the object in space (Battaglia et al, 2010; Carey & Allan, 1996; Chen, Sperandio, & Goodale, 2018; Sperandio, Kaderali, Chouinard, Frey, & Goodale, 2013). As a consequence, the object size estimation would be solely determined by vision (Camponogara & Volcic, 2021b). Alternatively, the visuo-haptic integration might occur both at the level of the position cues and at the level of size cues, but the dominance of the more reliable visual size cue would completely overshadow the haptic size cue, making it hard to determine whether the multisensory size information is truly integrated.…”

Reach-to-Grasp: A Multisensory Experience

“…Results show that the sensory modality did not affect size estimation for the large target, whereas small stimuli tended to be underestimated when judged relying on tactile information. Adopting a similar approach, Camponogara and Volcic ( 2019a , b , 2020 ) recently showed how the role of the sensory modality changes over time when the right hand grasps an object which is perceived through vision, or haptically, with the left hand. When only haptic information was available, wider grip aperture and earlier initiation characterized hand preshaping, whereas the final phase of the action was slower.…”