The Role of Skin Mechanics for Softness Exploration and Perception
Mon—HZ_13—Talks2—1602
Presented by: Didem Katircilar
People explore objects through various exploratory procedures to assess their properties, such as stroking a texture or pressing a soft object. They can also adjust specific parameters of their strategies, like applying more force to enhance precision (Kaim & Drewing, 2011). Individuals with finger pads that are more elastic and hydrated, or smaller in size, tend to show better precision in passive touch tasks (Deflorio et al., 2023). In the present study, we investigate whether these individual differences lead to different exploratory strategies (here: force-tuning) and whether they affect tactile precision in active softness perception. Participants completed two softness tasks in two sessions. In one session, hyaluronic acid was applied to their finger pad, while no treatment was given in the other. At the beginning and end of each session, elasticity and hydration were measured using cutometer and corneometer devices, and finger pad size was assessed with a caliper in three dimensions. We presented pairs of stimuli (Young’s Modulus: 41.5 vs. 45.0; 28.7 vs. 31.3 kPa) and participants chose the softer stimulus. In the unconstrained condition, participants could apply as much force as they wanted, while in the restricted condition, force was limited to 2N. Core findings were that hyaluronic acid increased elasticity and hydration, participants starting with hyaluronic acid used less force in the unconstrained condition (indicating slow initial force-tuning), and higher individual hydration and force levels together led to more accurate performance in both softness tasks. Overall, the results demonstrate tuning of exploration to skin mechanics.
Keywords: skin mechanics, haptic exploration, softness perception