Sensory redundancy and perceptual invariance in force production and object manipulation

Many real-world tasks involve exploratory movements for the manipulation of objects with a wide range of physical properties. Historically, neurophysiological research has emphasized how force sensations and perceptions arise due to descending motor commands and ascending afferent feedback from proprioceptors. However, how force sensation and perception contribute to stable percepts of handheld objects’ properties, such as moments of mass (moment, moment of inertia, etc.), to facilitate smooth interaction and manipulation is unclear. Studies have shown that wielding movements, and the associated Ia re-afferent activity, may be necessary to perceive a handheld object's moments of mass. Recent theoretical frameworks provide a novel basis to rethink how somatosensory information from different mechanoreceptors could be integrated with other sensory modalities, such as vision, to create stable percepts of object affordances associated with different moments of mass.