Infant color vision: A search for short-wavelength-sensitive mechanisms by means of chromatic adaptation

Abstract

Incremental thresholds for short- and middle-wavelength test spots, projected upon blue and yellow backgrounds, were determined for 2 mth old infants. Three out of four infants tested showed a change in relative sensitivity to 460 and 560 nm test spots with a change in the wavelength composition of the backgrounds, indicating the existence of at least two separately adaptable chromatic mechanisms. When infant spectral sensitivity under yellow adaptation was examined in more detail, however, it did not agree with that of adults tested under comparable conditions. In adults, the yellow background revealed a short-wavelength mechanism ( λ max = 440 nm ) in isolation, but did not do so in most 2 and 3 mth old infants. The infants who were least sensitive to short wavelengths on an absolute scale also deviated most from adult-like spectral sensitivity. We tentatively interpret this difference between adults and infants as an immaturity of the infant's short-wavelength-sensitive mechanism.