Development of chromatic discrimination in early infancy.

Combining a habituation-recovery paradigm with procedures to minimize brightness cues, we evaluated 1-3-month-olds' ability to discriminate among broadband mid- and long-wavelength stimuli. One-month olds showed evidence of discriminating a red (dominant lambda = 650 nm) from green (dominant lambda = 545 nm) but failed to discriminate either of these from a yellow (dominant lambda = 585 nm). At 2 months, infants showed evidence of discriminating 545-nm green from 585-nm yellow, but only at 3 months do they appear to discriminate 650-nm red from the yellow. Consistent with previous work, these data imply that chromatic discrimination emerges slowly over the first three postnatal months. Moreover, the developmental pattern is consistent with the notion that early human vision is limited by general rather than selective immaturities within the requisite retinal and neural mechanisms.