Chien, S: The Origin of Lightness Constancy

In adult lightness perception, the perceived lightness of a region is determined by at least two steps. First, the visual system computes the luminance ratios between that region and its surrounding areas (a local luminance ratio cue), and second, the region that has the highest luminance in a scene is assigned as white (a white anchoring cue). In this book, the author tested if infants as young as 4 months exhibit lightness constancy by use of a local luminance ratio cue and/or a white anchoring cue. Using a forced-choice novelty preference method, the author tested lightness constancy under three conditions: a constant white surround, a constant black surround, and a change of surround. Results showed that 4-mo- olds exhibited lightness constancy when both a local luminance ratio cue and a white anchoring cue were present. If the white anchoring cue was eliminated, or the local luminance ratios were changed, infants failed to show constancy. This pattern of results suggests that both a local luminance ratio cue and a white anchoring cue are necessary; either cue by itself is insufficient for achieving lightness constancy in early infancy.