Wavelength generalization and preference in monochromatically reared ducklings

Two experiments determined the effects of early color experience on gradients of wavelength generalization. In each experiment, one group of ducklings was raised in monochromatic (589 nanometers) sodium-vapor light and a second group, in white light. In Exp. I, ducklings pecked a key transilluminated by 589 nanometers. In a subsequent test, the group raised in white light produced steeper gradients. However, several monochromatically reared ducklings produced gradients as steep as those for the white-reared ducklings. In Exp. II, ducklings pecked a white line. In a subsequent test, using a fully illuminated key, subjects in both groups responded more often to "green" (510, 530, 550, or 570 nanometers) than to "non-green" wavelengths (490, 589, 610, or 650 nanometers). Ducklings raised in monochromatic light preferred shorter "green" wavelengths than ducklings raised in white light. This difference between the "green" preferences for the two groups accounted for most of the differences between the gradients of wavelength generalization obtained from the two groups in Exp. I after training at 589 nanometers.