Subtle to significant: Enhancing heaviness perception with stochastic resonance.

Dynamic touch allows individuals to perceive object properties such as weight and length through movement-based exploration. This study examined how subthreshold vibrotactile stimulation influences heaviness perception by leveraging the principles of stochastic resonance, which suggests that adding structured noise can enhance weak sensory signals. Specifically, we tested whether pink-noise stimulation (which mimics natural movement variability) improves perceptual accuracy more effectively than white noise or no stimulation. Ten participants completed wielding tasks while blindfolded, estimating the weight of objects under different noise conditions. Movement dynamics were analyzed using autoregressive fractionally integrated moving average modeling to assess the presence of long-range correlations (LRCs), a hallmark of fractal variability in biological systems. Results confirmed the presence of LRCs in wielding movements but revealed no consistent benefit of pink-noise stimulation on perceptual accuracy. Instead, we observed a complex interaction between noise type and object mass, with white noise increasing perceptual error at heavier weights. Contrary to expectations, stronger LRCs in wielding movements did not correlate with improved perception, suggesting that movement complexity alone does not guarantee perceptual accuracy. These findings challenge existing assumptions about the role of fractal dynamics in sensorimotor function and highlight the need for context-dependent models of stochastic resonance. Future research should explore how individual differences, task constraints, and stimulation intensity shape the effects of subthreshold noise on perception, with implications for sensory augmentation and rehabilitation strategies. (PsycInfo Database Record (c) 2026 APA, all rights reserved).