nontraversability

In this research we investigated perception of traversability in infants making independent trips in an unfamiliar environment. The overall plan was to put young ambulatory infants in a novel situation where surfaces varying in properties defining traversability or nontraversability stretched between the infant and a customary objective (a parent). […] Both crawling and walking subjects were observed when presented with surfaces having different affordances for walking as compared with crawling. The rigidity of a surface — its resistance to deformation — was chosen as the property to be focused on in the experiments to be reported. […] Earlier research (Gibson, Owsley, & Johnston, 1978; Gibson, Owsley, Walker, & Megaw-Nyce, 1979; Gibson & Walker, 1984) showed that even precrawling infants can discriminate differences in rigidity of objects that can be mouthed or handled. Here we asked whether the affordance of rigid and nonrigid surfaces was detected with respect to locomotion.

1994, E. J. Gibson, G. Riccio, M. A. Schmuckler, T. A. Stoffregen, D. Rosenberg, J. Taormina, “Detection of the traversability of surfaces by crawling and walking infants”, in Eleanor J. Gibson, editor, An Odyssey in Learning and Perception, MIT Press, →ISBN, page 574