Can you experience ‘top-down’ effects on perception?: The case of race categories and perceived lightness

Abstract

A recent surge of research has revived the notion that higher-level cognitive states such as beliefs, desires, and categorical knowledge can directly change what we see. The force of such claims, however, has been undercut by an absence of visually apparent demonstrations of the form so often appealed to in vision science: such effects may be revealed by statistical analyses of observers' responses, but you cannot literally experience the alleged top-down effects yourself. A singular exception is an influential report that racial categorization alters the perceived lightness of faces, a claim that was bolstered by a striking visual demonstration that Black faces appear darker than White faces, even when matched for mean luminance. Here, we show that this visually compelling difference is explicable in terms of purely low-level factors. Observers who viewed heavily blurred versions of the original Black and White faces still judged the Black face to be darker and the White face to be lighter even when these observers could not perceive the races of the faces, and even when they explicitly judged the faces to be of the same race. We conclude that the best subjectively appreciable evidence for top-down influences on perception does not reflect a genuinely top-down effect after all: instead, such effects arise from more familiar (if subtle) bottom-up factors within visual processing.

Current Controversies in Philosophy of Perception

“…Olkkonen et al 2008, Witzel et al 2011 between black and white faces, although perfectly genuine, turns out to be due to lowlevel features, not racial categories (Firestone and Scholl 2015). There is no change in how apertures look, and the contrary indication is likely a task compliance effect (Firestone and Scholl 2014 (Block 2014: 562-3).…”

The Face-Race Lightness Illusion Is Not Driven by Low-level Stimulus Properties: An Empirical Reply to Firestone and Scholl (2014)

“…Experiment 1 directly replicated the design of Firestone and Scholl (2014), using their stimuli. As did Firestone and Scholl, we used Amazon Mechanical Turk to recruit participants to complete a single trial experiment in which they viewed a pair of blurred faces and judged how light or dark they were, and then indicated whether they could identify the race of the faces.…”

“…They argued that the effect was based on social-categorical influence, and that the effect might rest on between-feature correlations between specific face forms and specific levels of luminance. Firestone and Scholl (2014) cited the Levin and Banaji stimuli as an important, experienceable demonstration of top-down effects on perception. In two experiments, they argued that at least some parts of the Levin and Banaji (2006) effect were attributable to low-level stimulus confounds because the brightness distortion appeared even when the faces were blurred to eliminate the perceptibility of race.…”

Visual experience: rich but impenetrable

“…It thus becomes rather difficult to assess whether they really visually experience high-level properties, such as anger, as opposed to judging them to be there. 10 10 A recent study by Firestone and Scholl (2015) questions the classic paper by Levin and Banaji (2006), in which they defend the influence of racial categories on the perception of lightness. Levin and Banaji (2006) report that when looking at faces with exactly the same luminance, Black faces appeared consistently darker than White faces, thus allegedly demonstrating the influence of relatively abstract concepts, such as race, on the perception of lightness.…”

“…Levin and Banaji (2006) report that when looking at faces with exactly the same luminance, Black faces appeared consistently darker than White faces, thus allegedly demonstrating the influence of relatively abstract concepts, such as race, on the perception of lightness. Firestone and Scholl (2015) have designed some experiments in which the images of Black and White faces are blurred to rule out racial recognition. The subjects in these experiments could not perceive the race of the faces and even explicitly judged the faces to be of the same race.…”