Mask-wearing selectivity alters observers’ face perception

Freud et al. Cognitive Research: Principles and Implications https://doi.org/10.1186/s41235-022-00444-z Cognitive Research: Principles and Implications (2022) 7:97 Open Access ORIGINAL ARTICLE Mask‑wearing selectivity alters observers’ face perception Erez Freud* , Daniela Di Giammarino and Carmel Camilleri Abstract Face masks became prevalent across the globe as an efficient tool to stop the spread of COVID-19. A host of studies already demonstrated that masks lead to changes in facial identification and emotional expression processing. These changes were documented across ages and were consistent even with the increased exposure to masked faces. Notably, mask-wearing also changes the state of the observers in regard to their own bodies and other agents. Previous research has already demonstrated a plausible association between observers’ states and their perceptual behaviors. Thus, an outstanding question is whether mask-wearing would alter face recognition abilities. To address this question, we conducted a set of experiments in which participants were asked to recognize non-masked faces (Experiment 1), masked faces (Experiment 2) and novel objects (Experiment 3) while they were either masked or unmasked. Mask wearing hindered face perception abilities but did not modulate object recognition ability. Finally, we demonstrated that the decrement in face perception ability relied on wearing the mask on distinctive facial features (Experiment 4). Together, these findings reveal a novel effect of mask-wearing on face recognition. We discuss these results considering the plausible effect of somatosensory stimulation on visual processing as well as the effect of involuntary perspective taking. Keywords: Face perception, Masks, Embodied cognition Significant statement During the COVID-19 pandemic, the use of face masks became prevalent across countries and societies in an effort to curb virus transmission. A host of studies already demonstrated that masks lead to changes in facial identification and emotional expression processing. Notably, an unexplored aspect of this phenomenon is whether mask-wearing (i.e., when the observers wear a mask) also changes how we perceive faces. This question pertains to more general research domains with implications for everyday life: How does the state of an observer, in relation to their own body and other individuals, modulate their perceptual behaviors? In a series of experiments, we demonstrate that mask-wearing hinders observers’ ability to recognize masked and non-masked faces. This effect *Correspondence: Department of Psychology and Centre for Vision Research, York University, Toronto, Canada is specific to face recognition, and evident only when observers wear a mask that occlude distinctive facial features. These results provide timely insights into the effect of mask-wearing on visual perception and also reveal non-visual processes that modulate the way we perceive the world around us. Introduction The onset of the COVID-19 pandemic saw an unprecedented rise in the use of face masks among members of the general public as governments around the world mandated mask-wearing in public spaces (Canada, 2020). This new constraint was introduced in an effort to curb virus transmission and allow for the safe re-opening of educational, economical and recreational institutions. Despite playing a crucial role in facilitating a return to normalcy, masks have propelled society into a new arena of facial recognition, one in which familiar and unfamiliar faces alike are now partially obscured from view. © The Author(s) 2022. Open Access This article is licensed under a Creative Commons Attribution 4.0 International License, which permits use, sharing, adaptation, distribution and reproduction in any medium or format, as long as you give appropriate credit to the original author(s) and the source, provide a link to the Creative Commons licence, and indicate if changes were made. The images or other third party material in this article are included in the article’s Creative Commons licence, unless indicated otherwise in a credit line to the material. If material is not included in the article’s Creative Commons licence and your intended use is not permitted by statutory regulation or exceeds the permitted use, you will need to obtain permission directly from the copyright holder. To view a copy of this licence, visit http://creativecommons.org/licenses/by/4.0/. Freud et al. Cognitive Research: Principles and Implications (2022) 7:97 Page 2 of 10 Consistently, a great deal of research has been dedicated to estimating the effect of masks on face perception. Recent studies have found that masks pose a considerable challenge to face perception among adult populations, producing consistent deficits in face recognition abilities and leading to reduced holistic processing (Carragher & Hancock, 2020; Freud et al., 2020, 2022). Others have found that the occlusion of the lower face by a sanitary mask or scarf hinders our ability to interpret facial expressions (Calbi et al., 2021; Carbon & Serrano, 2021). Moreover, a recent study by Stajduhar and colleagues (2022) demonstrated that school-age children-much like adults-show a robust impairment in recognition of masked faces. Research thus far has focused on what happens to observers’ face perception abilities when they are tasked with identifying others who wear a mask. However, it is essential to also consider the complementary situation: what happens to face perception abilities when the observers are the ones wearing the mask, particularly when the mask occludes distinctive face features that contribute to recognition? This question pertains to a more general research domain—to what extent do the state of the observers, in relation to their own body and to other agents modulate the way in which they process faces and other visual stimuli? The effect of the observers’ bodily state on sensory processing was often explored by manipulating the body’s orientation relative to visual stimuli. In a previous study, body position was systematically manipulated while participants were asked to recognize letters and faces. The authors found a robust influence of body orientation on both categories, with a greater effect on face recognition (Barnett-Cowan et al., 2015). Along similar lines, superior face recognition performance was observed when participants were presented with egocentrically upright faces (i.e., faces that appear upright with respect to the observer’s body position) compared with environmentally upright faces (i.e., faces that appear upright with respect to the room they are in) (Davidenko & Flusberg, 2012). The effect of bodily states on fundamental perceptual behaviors was also demonstrated beyond face processing. For example, Kim and colleagues (2021) used virtual reality to show that body orientation affects the perceived size of visual targets, making objects appear smaller and (...truncated)