Abstract
BACKGROUND The Face-Lightness Distortion Effect (FLDE) is an illusion causing African American faces to appear to be darker than Caucasian faces when matched for mean luminance and contrast (Levin & Banaji, 2006, J Exp Psychol Gen.; Nichiporuk et al., 2017 VSS). However, studies of the FLDE have predominantly used Caucasian participants, and an open question is the extent to which FLDE depends on the race of the observer. Here, the FLDE is measured using maximum likelihood conjoint measurement (MLCM) and for groups of African American and Caucasian observers. METHODS The joint influence of (1) overall mean luminance and (2) race of face on perceived face lightness was measured for 13 African American and 12 Caucasian observers. Thirteen African American faces ranging in mean luminance and contrast and 13 Caucasian faces, matched to the African American faces in mean luminance and contrast, were tested. Most pairs of 26 faces (either upright or inverted, in separate runs) were presented straddling fixation for 250 msec, followed immediately by a random noise mask (with replications, 1,800 judgments for each observer.) Perceptual lightness scales for all 26 stimuli were derived from MLCM. RESULTS & CONCLUSIONS Face race had a significant effect on perceived face lightness for the upright condition for 11 of 13 African American observers (p < 0.01), in the direction of a fixed decrement in face lightness for African American faces. The effect was significantly reduced for inverted compared to upright faces. For 12 out of 12 Caucasian observers, stimulus race also affected perceived face lightness (p < 0.001), again in the direction of a fixed decrement in face lightness for African American faces. Also, the effect was significantly reduced in the inverted compared to upright condition. Overall, the results show the FLDE is found for observers of both races.
Meeting abstract presented at VSS 2018