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. Here we report in face perception the existence of effects similar to contextual modulation. In five experiments we increased or decreased contrast between facial skin and adjacent image regions to determine whether this modulates the appearance of skin evenness and wrinkles. Methods and Results We first found that an occluding grid placed over images of skin affected ratings of skin evenness. Skin appeared more even when the grid was black than when its luminance matched the skin tone. In a subsequent experiment with full-face images we found that skin appeared less wrinkled and more even when occluded by black bars than skin-toned bars. We next manipulated contrast by keeping the skin unchanged but increasing or decreasing the luminance and color of the facial features. Again, skin appeared more even and less wrinkly when contrast was increased. Critically, this was found for inverted as well as upright faces, consistent with a low-level contrast mechanism but not a face-specific mechanism. In a final experiment, we applied typical makeup to the facial features but no products were applied to the skin. Despite the skin appearance being physically identical, skin appeared more even and less wrinkled when makeup was applied to the features. Conclusions We showed that facial skin appearance is affected by contrast with adjacent surfaces. This includes contrast with the facial features, which can be modified through makeup. Preliminary evidence indicates that other forms of personal decoration such as hair coloring, clothing, and jewelry can also affect skin appearance through contrast suppression or enhancement. This suggests the exciting possibility of linking such cultural practices to the structure and function of the visual system.
Meeting abstract presented at VSS 2018