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.

The unprecedented effort to minimize the effects of the COVID-19 pandemic introduces 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, the mostvalidated measure of face perception abilities in humans. As expected, a substantial decrease in performance was found for masked faces, along with a large increase in the proportion of individuals who exhibit a remarkable deficit in face perception. Unexpectedly, however, the inclusion of masks led to a qualitative change in the way masked faces are perceived. In particular, holistic processing, the hallmark of face perception, was severely impaired for maskedfaces. Similar changes were found when masks were included either during the study or the test phases of the experiment. Together, we provide robust evidence for qualitative alterations in the processing of masked faces that could have significant effects on daily activities and social interactions.

Face perception is considered a remarkable visual ability in humans that is subject to a prolonged developmental trajectory. In response to the COVID-19 pandemic, mask-wearing has become mandatory for adults and children alike. Recent research shows that mask-wearing hinders face recognition abilities in adults, but it is unknown if the same holds true in school-age children in whom face perception is not fully developed. Here we tested children (n = 72, ages 6–14 years old) on the Cambridge Face Memory Test – Kids (CFMT-K), a validated measure of face perception performance. Faces were presented with or without masks and across two orientations (upright/inverted). The inclusion of face masks led to a profound deficit in face perception abilities. This decrement was more pronounced in children compared to adults, but only when task difficulty was adjusted across the two age groups. Additionally, children exhibited reliable correlations between age and the CFMT-K score for upright faces for both the mask and no-mask conditions. Finally, as previously observed in adults, children also showed qualitative differences in the processing of masked versus non-masked faces. Specifically, holistic processing, a hallmark of face perception, was disrupted for masked faces as suggested by a reduced face-inversion effect. Together, these findings provide evidence for substantial quantitative and qualitative alterations in the processing of masked faces in school-age children.

Face perception is considered a remarkable visual ability in humans, which is subject to a prolonged developmental trajectory. In response to the COVID-19 pandemic, mask-wearing has become mandatory for adults and children alike. However, previous research indicates its adverse effects on face recognition abilities in adults. The current study sought to explore the effect of masks on face processing abilities in school-age children given that face perception is not fully developed in this population. To this end, children (n = 72, ages 6-14 years old) completed the Cambridge Face Memory Test – Kids (CFMT-K), a validated measure of face perception performance. Faces were presented with or without masks and across two orientations (upright/inverted). The inclusion of face masks led to a profound deficit in face perception abilities. This decrement was more pronounced in children compared to adults, despite adjustment of task difficulty across the two age groups. Additionally, children exhibited reliable correlations between age and the CFMT score for upright faces for both the mask and no-mask conditions. Finally, as previously observed in adults, children also showed qualitative changes in the processing of masked faces. Specifically, holistic processing, a hallmark of face perception, was disrupted for masked faces, as suggested by a reduced face-inversion effect. Together, these findings provide evidence for substantial quantitative and qualitative alterations in the processing of masked faces in school-age children.

Face masks became prevalent across the globe to minimize the effects of the COVID-19 pandemic. Previous research highlighted their negative qualitative and quantitative impact on face recognition. An outstanding question is whether these effects would attenuate following persistent natural exposure to masked faces in the era of the pandemic. This question also pertains, more generally, to potential effects of training on face recognition in natural settings. 1,236 participants were tested on masked, non-masked, upright and inverted versions of the Cambridge Face Memory Test (CFMT) at different time points over one year. The results showed persistent deficits in recognizing masked faces across time points. This was followed by persistent qualitative change, a reduced inversion effect for masked compared to non-masked faces. Together, these findings provide compelling support for the idea that the mature face processing system in humans is rigid in nature, even following prolonged, real-life exposure to altered faces.