Deciphering Contact Interactions and Exploration Strategies Underlying Tactile Perception of Material Softness

Our sense of touch is essential and permeates in interactions involving natural explorations and affective communications. For instance, we routinely judge the ripeness of fruit at the grocery store, caress the arm of a spouse to offer comfort, and stroke textiles to gauge their softness. Meanwhile, interactive displays that provide tactile feedback are becoming normal and ubiquitous in our daily lives, and are extending rich and immersive interactions into augmented and virtual reality. To replicate touch sensation and make virtual objects feel tangible, such feedback will need to relay a sense of compliance, or softness, one of the key dimensions underlying haptic perception. As our understanding of softness perception remains incomplete, this study seeks to understand exploratory strategies and perceptual cues that may optimally encode material softness. Specifically, we employ methods of computational finite element modeling, biomechanical experimentation, psychophysical evaluation, and data-driven analysis. Overall, this work may aid in engineering the next-generation wearable haptic displays, which must be more tangible, compatible, and perceptually naturalistic.