Abstract
Introduction: Apparent contrast can be suppressed or enhanced when presented within surrounding images. This contextual modulation is typically accounted for by models of contrast gain control. Recently we reported that skin appearance is affected by contextual modulation (Russell et al. VSS 2018). Here we report two studies demonstrating that skin appearance is affected by background color and by hair color. Methods and Results: In Study 1, controlled images of 45 German women from the FACES database were presented surrounded by either a black or a skin-colored oval-shaped mask such that only the internal features of the face were visible. In Study 2 we selected 41 faces from the FACES database and presented them unmasked, but with their hair either darkened or lightened in the L* dimension. In both studies participants rated how even and how wrinkled the skin appeared. Thus in both studies we investigated the effect of surrounding the skin with image regions that had high or low contrast with the facial skin. In Study 1 skin appeared more even and less wrinkled when surrounded by a dark background than a skin-colored background. In Study 2 skin appeared more even but no less wrinkled when surrounded by dark hair than by light hair. Across both studies, increased contrast with surrounding image regions resulted in more even-looking skin. However, increased contrast from an oval mask but not from darker hair resulted in skin appearing less wrinkled. Conclusions: We found evidence for contextual modulation of skin appearance by the image region surrounding the face, whether it was hair or an image mask. The finding that hair color affects apparent skin evenness suggests that artificially coloring the hair could offer an indirect route by which a person can influence the appearance of their skin.