Root Mean Square Contrast andmean luminance (pixel intensity) of
the pictures were calculated using custom Matlab (Mathworks, Inc.)
scripts (see Table 1). Houses and intact faceswere compared using independent
t-tests (two-tailed, equal variance not assumed) and intact andeyeless faces were compared using paired sample t-tests (two-tailed).
Compared to house stimuli, mean luminance was greater (t(39.2) =
−11.09, p b 0.001) and contrast was lower (t(43.9) = 44.02, p
b 0.001) for face stimuli. Luminance was also greater (t(39) = −25.5,
p b 0.001) and contrast was lower (t(39) = 32.9, p b 0.001) for eyeless
compared to intact faces, as expected given the removal of the high contrast
zone that eyes represent.