The COVID-19 pandemic masks the way people perceive faces

Abstract

The unprecedented efforts to minimize the effects of the COVID-19 pandemic introduce a new arena for human face recognition in which faces are partially occluded with masks. Here, we tested the extent to which face masks change the way faces are perceived. To this end, we evaluated face processing abilities for masked and unmasked faces in a large online sample of adult observers (n = 496) using an adapted version of the Cambridge Face Memory Test, a validated measure of face perception abilities in humans. As expected, a substantial decrease in performance was found for masked faces. Importantly, the inclusion of masks also led to a qualitative change in the way masked faces are perceived. In particular, holistic processing, the hallmark of face perception, was disrupted for faces with masks, as suggested by a reduced inversion effect. Similar changes were found whether masks were included during the study or the test phases of the experiment. Together, we provide novel evidence for quantitative and qualitative alterations in the processing of masked faces that could have significant effects on daily activities and social interactions.

Figure 1

Examples of faces with and without masks similar to the ones used in the experiment. Faces are reproduced with premission from the Chicago Face Database.

Figure 2

Results of Experiment 1: (A) Results of the CFMT experiment for non-masked and masked and faces. The dashed black horizontal line represents chance level (also in panel D). Performance was significantly impaired for masked faces. An inversion effect was found for masked and for non-masked faces, but it was significantly reduced for masked faces. For all figures, error bars represent the 95% confidence interval for the main effect of group (mask/no mask). (B) Distribution of CFMT results across the different conditions. (C) Distribution of the CFMT results across the different conditions separately for female and male participants. Females performed better than males across all conditions. (D) Analysis of the separate phases of the CFMT. An advantage for non-masked faces was found across all levels, including level 4, in which overall performance was close to chance level. The green dashed horizontal line represents the maximal score.

Figure 3

Results of Experiment 2: (A) Results of the CFMT experiment when faces were masked only during the test phase or the study phase. The results are similar to those obtained from the group in which faces were masked during both study and test phases. (B) Correlation between self-reported face perception abilities (extended PI20) and the CFMT results for upright and inverted faces.