Lightness, Embeddedness, and Contrast

Abstract

A rnonocularly observed, upright trapezoid appeared darker than when observed binocularly, but it also appeared slanted under monocular and upright under binocular viewing. When slanted, it may be said to have been more embedded in its background. When embeddedness was then controlled, the lightness difference between monocular and binocular viewing was markedly reduced toward zero. These effects were independent of the location of the illuminating-source. Although the results could be interpreted to mean that one percept influences a second, it should be noted that the cited mean effects were never greater than .11 log ft-L.