Multifractal Auditory Stimulation Promotes the Effect of Multifractal Torso Sway on Spatial Perception: Evidence from Distance Perception by Blindwalking

Stimulation and movement interact non-linearly across multiple scales—a point empirically and quantitatively available through multifractal structure. Multifractal movements might implicate multifractal stimulation. Previous correlational modeling of accelerometry-measured torso movements during blindwalking indicated that multifractality in movement predicts distance-perceptual judgments. We now experimentally tested whether multifractal stimulation interacted with multifractal torso movement to support distance perception. We edited music-like sounds to manipulate multifractal non-linearity in auditory stimulation through headphones to participants perceiving distance by blindwalking—with eyes closed both during Lap-1 distance instruction and Lap-2 distance replication. Stimulation non-linearity significantly interacted with torso movements to predict distance-replication judgments. Low stimulation non-linearity showed no effect. Medium stimulation non-linearity interacted with Lap-2 torso non-linearity to produce over-/underestimation of shorter/longer distances. Higher auditory non-linearity led Lap-2 distance replication enlisted longer time scales, drawing on prior torso non-linearity, i.e. from Lap 1, and producing overestimation proportionally with a greater standard deviation of torso movements. Distance perception by blindwalking appears more accurate under medium rather than excessive non-linearity, resonating with previous evidence that walking engenders less multifractality than other movements. Movement-dependence of stimulation is also unsurprising to ecological-psychology wisdom. However, to our knowledge, present results constitute an unprecedented step toward elaborating movement-dependence to multifractal-geometrical approaches to perception.