To understand the nature of pair preferences, pair harmony, pair similarity, and figural color preference beyond the findings described in the main article, we examined the effects of the component colors' cuts through color space -saturated (S), light (L), muted (M) and dark (D) -as a function of the hue difference between the two colors. There were no data points for same-cut pairs with zero hue difference because the component colors were identical, so we conducted separate ANOVAs on two data sets. The first ANOVA included only hue-difference steps of 1 through 4 for all cut comparisons (hereafter "∆1-4, all cuts"). The second ANOVA included all five hue-difference steps (0 through 4) but only for cut comparisons in which the figure and ground were from different cuts (hereafter "∆0-4, different cuts"). The y-axis limits in Figures S1 (pair preference), S2 (harmony), and S4 (similarity) are the same to allow direct comparisons between the figures. The scale for figural color preferences in Figure S6 is different, however, because those data were collected on a different ratings scale (1-9) than that the other three measures (-100 to 100). As shown in Figure S1 , pair preferences for all cut combinations decreased monotonically as hue difference between the figure and ground color increased (∆1-4, all cuts: F(3,141) = 27.83, p < .001); ∆0-4, different cuts: F(4,188) = 51.08, p < .001). There was a 3-way interaction among figure cut, ground cut, and hue difference (∆1-4, all cuts: F(27,1269) = 2.22, p < .001; ∆0-4, different cuts: F(24, 1128) = 4.31, p < .001), but the size of this interaction is small, its nature is unsystematic, and its interpretation is unclear. The simpler figure cut x hue difference interaction was systematic, however, with preference for pairs with D and M figures decreasing more rapidly than pairs with S and L figures as hue difference increased (∆1-4, all cuts: F(9, 423) = 2.25, p < .05; ∆0-4, different cuts: F(8, 376) = 4.29, p < .001). There was no such interaction between ground cut and hue difference (∆1-4, all cuts: F(9, 423) = 1.16, p > .05; ∆0-4, different cuts: F(12, 564) = 1.61, p > .05). Figure S1 . Pair preference ratings for figural color (separate lines) and ground color (separate graphs) of the display for each cut, as a function of the hue difference between the figure and ground colors. As described in the main article, pair-wise comparisons of cut combination showed that the only effects of cut occurred for the saturated ground conditions: Combinations with saturated figures on saturated grounds were preferred to those with light, muted and dark figures on saturated grounds (t(47) = 3.74, 6.33, 3.56, p < .002), and those with light figures on saturated grounds were preferred to those with muted figures on saturated grounds (t(47) = 3.64, p < .002). Pairwise comparisons between harmony ratings are shown in Figure S3 . In summary, combinations that contained lighter and less saturated colors tended to be rated as more harmonious, in that L figures were judged most harmonious against all four ground cuts, and either D or S figures were judged least harmonious against all four ground cuts. Figure S3 . Comparisons between harmony ratings of color combinations with the same ground cut (separate quadrants) and different figure cuts. Icons adjacent to each row column represent the cuts of the figure-ground pairs that were judged. The lower triangle of each ground-cut matrix shows the results of t-tests (df = 47, *p ≤ .002, using the Bonferroni correction) and direction of the difference (e.g., "L > S" in the Saturated Ground quadrant indicates that light figures on saturated grounds were judged more harmonious than saturated figures on saturated grounds). The upper triangle of the matrix shows the means of the pairs that were compared. The means for comparisons with same-cut pairs (italicized text) include only hue-difference steps of 1-4 for both pairs. All other means include all hue-differences steps (0-4). Bold face text indicates differences were significant. (Note: In this diagram, the figure squares are colored slightly lighter than the ground to increase discriminability for same-cut pairs.) Figure S4 shows pairwise similarity ratings for left and right region cuts as a function of hue difference between the two colors. Similar to pair preference and harmony ratings, similarity ratings decreased monotonically as the hue difference between the component colors increased Figure S5 . Comparisons between similarity ratings of color combinations with the same left region cut (separate quadrants in the figure) and different right region cuts. Icons adjacent each row and column represent the cuts of the pairs that were judged. The lower triangle of the matrix shows the results of t-tests (df = 47, *p ≤ .002 (using the Bonferroni correction) and direction of the difference (e.g., in the "Saturated Left" quadrant, "S > D" indicates that saturated colors (left) are more similar to saturated colors (right) than to dark colors (right)). The upper triangle of the matrix shows the means of the pairs that were compared. The means for comparisons with samecut pairs (italicized text) include only hue-difference steps of 1-4 for both pairs. All other means include all hue-differences steps (0-4). Bold face text indicates differences were significant. There was a 3-way interaction (∆1-4, all cuts: F(27,1269) = 14.30, p < .001; ∆0-4, different cuts: F(24,1128) = 12.36, p < .001), between left region cut, right region cut, and the hue difference between the two. Not surprisingly, color pairs with similar lightness were judged to be most similar (see Figure S5 for specific comparisons), which was different from harmony ratings in which pairs that were generally lighter were more harmonious (compare Figures 7 and 11 in the main article). Similarity ratings decrease at different rates as hue difference increases, which is also evident in minor interactions between hue difference and left color cut (∆1-4, all cuts: F(9, 423) = 3.03, p < .001); ∆0-4, different cuts: F(12, 564) =16.55, p < .001, excluding same-cut pairs) and right color cut (F(9, 423) = 2.1, p < .05, F(8, 376) = 12.73, p < .001, excluding same-cut pairs). Unlike pair preference, harmony and similarity ratings, figural color preference ratings did not decrease as hue difference between the figure and ground increased for all cut combinations ( Figure S6 ). There was a 3-way interaction between figural cut, background cut,
On the contrary, Schloss et al. REF show that pair preference -defined as how much an observer likes a given pair of colors as a Gestalt, or whole -decreases monotonically as a function of the difference in hue.