Lightness constancy in 4-month-old infants.

In the present study, discrete trial familiarization/novelty techniques were used to study lightness constancy in 4-month-old infants. The test stimuli were real objects (paper smiley faces) of two different reflectances, dark gray (17% reflectance) and light gray (54% reflectance). In Experiment 1, the test stimuli were viewed against a white (90% reflectance) surround, and in Experiment 2, against a black (4.6% reflectance) surround. In Experiments 1 and 2, the illumination was changed between familiarization and test phases of each trial. In Experiment 3, the reflectance of the surround was changed from white to mid gray (28.5% reflectance) between familiarization and test phases of each trial. With the white surround, the infants preferred the face with the novel reflectance, consistent with the presence of lightness constancy. With the black surround, the infants showed no preference between faces with novel reflectance vs. novel luminance. With the changing surround, the infants showed a small preference for the stimulus with the novel ratio, as opposed to the stimulus with the novel reflectance and the novel luminance. The results are discussed in the context of adult cues for lightness constancy, including white anchor points and local luminance ratios.