Figure 5.

Manipulations of background similarity between adapting and test faces. Each face set contained expressions ranging from sad to happy, but only the saddest one is shown here. a, Cartoon face set with random dots added (cf_d). Random dots of 15% density were added to the original static cartoon face set in Figure 1d. b, Luminance-matched cartoon face set (cf_l). The background luminance was matched to the mean background luminance of cf_d set. c, Cartoon face sets with 1/f^k noise backgrounds, with k = 0, 0.5, 1, 1.5, 2, and 2.5, respectively. Noises with different k values had the same first-order luminance distribution but different second-order correlation structures. A uniform background was also included and labeled as k = ∞.