An empirical study of the achromatic Mach card effect (2002)

Author(s): Bloj MG, Hurlbert AC

    Abstract: The traditional achromatic Mach card effect is an example of lightness inconstancy and a demonstration of how shape and lightness perception interact. We present a quantitative study of this phenomenon and explore the conditions under which it occurs. The results demonstrate that observers show lightness constancy only when sufficient information is available about the light-source position, and the perceptual task required of them is surface identification rather than direct colour-appearance matching. An analysis and comparison of these results with the chromatic Mach card effect (Bloj et al 1999 Nature 402 877 - 879) demonstrate that the luminance effects of mutual illumination do not account for the change in lightness perception in the traditional Mach card.

      • Journal: Perception - special issue "Scene Articulation: Colour and Lightness Constancy
      • Volume: 31
      • Issue: 2
      • Pages: 233-246
      • Publisher: Pion Ltd.
      • Publication type: Article
      • Bibliographic status: Published