Nonlinear pattern vision processes in early infancy

Abstract

This study explored a possible nonlinear process in the pattern vision of 1 1 2 - to 3-month-old human infants by using a herringbone pattern. Adults perceive a global orientation in this pattern from the arrangement of local line segments oriented at right angles to each other. Fourier analysis of this pattern, however, shows no power at the perceived global orientation. In essence, no linear filtering of this pattern will yield energy in the perceived global orientation of the herringbone pattern. Infant perceptual theories based on the linear systems approach would predict that infants should be insensitive to this global orientation of the herringbone. Results of a preference procedure in Experiment 1 showed that 12-week-olds preferred the globally vertical and horizontal herringbones over the oblique herringbones. This preference is not predicted by linear systems accounts of pattern preferences. Experiment 2 provided converging evidence for nonlinear pattern vision processes at 12 weeks of age using a habituation procedure. Taken together, these results indicate that nonlinear pattern vision processes are functional by 3 months of age in the human visual system.