Abstract
Recent advances in cross-cultural studies emphasized the importance of including diversified groups of participants to better understand mechanisms underlying various face processing abilities, whether they reveal a difference or not (e.g. Blais et al., 2021). In visual psychophysics, little is known about visual strategies underlying face perception among Black observers. Therefore, we investigated visual strategies in Black and White participants in a Gender and Expressiveness (ExNex) tasks, using a newly validated platform, Pack & Go by VPIXX, which allows high quality psychophysic testing online. Sixty participants (15 Blacks and 45 Whites) completed both experiments (4000 trials per participant) conducted using the Bubble’s technique (Gosselin & Schyns, 2001) which samples visual information on a trial-by-trial basis using small gaussian windows in order to reveal the most useful information in any visual task. Accuracy was maintained at 75% by adjusting online the number of bubbles using QUEST (Watson & Pelli, 1983). Group performance levels were controlled by matching individual Black participants with White participants according to their final average number of bubbles in both tasks. Classification images were produced by calculating a weighted sum of the bubbles mask, using the trial-by-trial accuracy transformed into z-scores as weights. Pixel tests from the Stat4CI (Chauvin et al., 2005) toolbox revealed significant pixels associated with performance (p< .05; Zcrit = 4.05). Mainly, both groups made use of the same visual information for both race stimuli, that is, reliance on the eye in the Gender task and on the mouth in the ExNex task. Interestingly, Black participants also relied significantly more on the left eye for ExNex judgements, but only with Black stimuli. These differences and similarities in visual strategies for Black and White observers, will be discussed regarding cross-cultural differences in face perception in general.