  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.
