Figure 4
Comparisons of unmasked vs KN95 valence scores (x-axis) for three mental states that showed different degrees of valence changes. Lighter datapoints are individual ratings, and darker datapoints are the mean ratings in the 2D grid. Nodding forward (i.e. negative pitch) makes positive expressions appear more negative in the KN95 condition (A). On the contrary, nodding backward (i.e. positive pitch) helps preserve the positive valence (B), and renders negative mental states more positive. (C). Other predictors of valence are frowning (AU 4), raising the cheeks (AU 6) and smiling (AU 12). Face images were obtained with permission from the public McGill Face Database32.
