The role of fractality in perceptual learning: exploration in dynamic touch

Perceptual systems must learn to explore and to use the resulting information to hone performance. Optimal performance depends on using information available at many time scales, from the near instantaneous values of variables underlying perception (i.e., detection), to longer term information about appropriate scaling (i.e., calibration), to yet longer term information guiding variable use (i.e., attunement). Fractal fluctuations in explorations would entail fluctuation at all time scales, allowing perceptual systems a flexible way to detect information at all time scales. We tested whether perceptual learning in dynamic touch is related to the fractality of wielding behaviors. A reanalysis of wielding behaviors from Arzamarski, Isenhower, Kay, Turvey, and Michaels (2010) revealed that exploratory movements were fractal and that a fractal-scaling exponent predicts individual differences in haptic judgments.