Perceptual Learning

Traditionally, researchers viewed motor development in terms of neural-muscular maturation. Development was considered largely a matter of muscles and biomechanics and the underlying mechanisms were thought to be maturational. My research has highlighted the important role of experience in motor skill acquisition and the essential role of perceptual exploration in controlling motor actions adaptively. Using innovative paradigms that allow continuous scaling of environmental features (slopes, gaps, apertures, drop-offs, etc.) and experimental manipulation of body properties (e.g., slippery Teflon shoes or floors), we have examined infants’ ability to match their motor decisions to the actual affordances for action. Borrowing experimental methods from perceptual psychophysics (curve fitting algorithms, staircase procedures, etc.), we test infants in dozens of trials per session yielding extremely rich data about the accuracy and informational basis of their decisions. Using new observational techniques (checklist diaries, telephone diaries, step-counters, video-tracking), we have collected the first data on infants’ everyday locomotor experiences.

Several important and surprising findings have resulted from this work. First, infants acquire an immense quantity of experience with balance and locomotion (e.g., a typical toddler travels more than 39 football fields/day, and accumulates an average of 15 falls/hr). Second, the duration of infants’ experience has tremendous predictive power, explaining significant portions of variance in developmental changes above and beyond that explained by infants’ body dimensions and chronological age. Third, learning from everyday experience is specific to each perception-action system in development. That is, sitting, crawling, cruising, and walking show separate learning curves, even for responses in the same tasks. Finally, experience with surfaces varying in friction and rigidity promotes only narrow transfer to situations with the same visual context.