The contrast sensitivity of human infants to gratings differing in duty cycle.

Human infants' contrast thresholds for rectangular wave gratings differing in duty cycle were measured. The forced-choice preferential looking technique was used to estimate thresholds in fifteen 8- to 10-week old infants. The results indicated that contrast threshold varied systematically with duty cycle. Our findings were consistent with the predictions of a linear, multiple channel model and one version of a linear, single channel model but were inconsistent with the predictions of a contour density and another version of a single channel model.