Preference for single colors
Experiment 1 measured students’ preferences for four colors specifically matched to the characteristic colors found on apparel sold at the university store: Berkeley blue (Berkeley’s primary color, a very dark, slightly purplish “navy” blue), Berkeley gold (Berkeley’s secondary color, a nonmetallic, highly saturated orangish yellow), Stanford red (Stanford’s primary color, a dark, highly saturated, slightly orangish “cardinal” red), and Stanford white (Stanford’s secondary color, a prototypical white). These four colors were randomly intermixed with the 32 chromatic colors studied by Palmer and Schloss (2010) and four other, achromatic, colors so that participants would be unlikely to realize that the experiment concerned Berkeley and Stanford colors, since they comprised only 10% of the trials (if white is included; 7.5% if white is not included). Participants’ responses were therefore unlikely to reflect “demand characteristics.” The participants later rated their amount of school spirit for their own university, which was then correlated with color preferences.
Method
Participants
Fifty-seven Berkeley participants (75% female) were tested at Berkeley and 46 Stanford participants (72% female) were tested at Stanford. No participants were color deficient when screened with the Dvorine Pseudo-Isochromatic Plates. All gave informed consent, and the Committee for the Protection of Human Subjects at the University of California, Berkeley, approved the experimental protocol.
Design
The 40 colors tested in this experiment (see Table 1) included the 32 chromatic colors from the Berkeley Color Project (BCP; see Palmer & Schloss, 2010), the four university-specific colors (Berkeley blue, Berkeley gold, Stanford red, and Stanford white), and four achromatic colors (black and three intermediate grays). Table 1 shows the Munsell coordinates and the corresponding CIE 1931 xyY coordinates obtained from the Munsell renotation table (Wyszecki & Stiles, 1967). The three chromatic university-specific colors were determined by perceptual matches in daylight between standard, unused Berkeley and Stanford apparel and Munsell chips (glossy series) and were converted to CIE xyY coordinates using the same Munsell renotation table. The chromaticity for all achromatic colors (including Stanford white) was CIE Illuminant C (x = .310, y = .316), which appeared achromatic against the background color, which had essentially the same chromaticity.
Table 1 CIE 1931 values and Munsell values for the 32 chromatic colors (from Palmer & Schloss, 2010) and CIE 1931 values for the four achromatic colors (CIE Illuminant C) and the four university-specific colors
Displays
Each display consisted of a 100 × 100 pixel square centered on the computer monitor above a 400-pixel response scale. Stanford students completed the experiment on a 19-in. Dell E196FPf monitor (1,024 × 768 resolution), and Berkeley students on either the same Dell monitor or a 20-in. iMac computer (1,280 × 768 resolution), both calibrated using a Minolta CS100 chroma meter. The software Presentation (www.neurobs.com) was used to generate and display test items during the experiment.
Procedure
The colors were presented one at a time in a random order. Participants were instructed to rate how much they liked each color, on a scale from not at all to very much. Ratings were made by moving the cursor along the response scale with the computer mouse and clicking at the appropriate position. Ratings were rescaled to range from –100 to +100, with the vertical bisecting line for the neutral preference point at 0. Colors remained on the screen until a response was made, and the next trial began 500 ms later. Later in the session, participants rated their level of spirit for their own university on a 1 – 9 scale (1 = anti-spirit to 9 = tons of spirit, with 5 indicated as a neutral point of no spirit) and their level of investment in the Berkeley–Stanford rivalry on a 1 – 9 scale (1 = not at all, 9 = intensely, with 5 = moderately). They also reported which side of the rivalry they were on.
Results and discussion
We compared Berkeley and Stanford students’ overall preferences for the university colors by computing a composite Berkeley–Stanford difference score for each participant: the mean preference rating for Berkeley blue and Berkeley gold minus that for Stanford red and Stanford white. Students at the two universities differed on this combined measure [F(1, 101) = 8.21, p < .01, η2 = .08],Footnote 2 in that Berkeley students liked Berkeley’s colors more than Stanford’s (+16.1), and Stanford students liked Stanford’s colors more than Berkeley’s (–9.6). The EVT further predicts that differences in color preferences should covary with students’ levels of school spirit. Indeed, the Berkeley–Stanford composite score was positively correlated with school spirit for Berkeley students (r = +.26, p < .05) and negatively correlated with school spirit for Stanford students (r = –.29, p < .05).
Figure 1a compares Berkeley and Stanford students’ preference ratings separately for the individual school colors. All four differences were in the predicted direction (p = .06 by a sign test), although not all were individually reliable. Stanford students liked Stanford red more than Berkeley students did [F(1, 101) = 8.92, p < .01, η2 = .08], and there was a marginally significant trend for Berkeley students to like Berkeley gold more than Stanford students did [F(1, 101) = 2.30, p = .07, η2 = .02]. No reliable differences in preference were evident for Berkeley blue [F(1, 101) = 0.07, p = .40, η2 = .001] or Stanford white [F(1, 101) = 0.07, p = .39, η2 = .001].
These comparisons show that the difference between Berkeley and Stanford students’ composite preference scores was driven primarily by preference differences in Stanford red and Berkeley gold. The lack of an effect for white may be attributed to the fact that it is well represented in both Berkeley and Stanford’s football uniforms, as well as in many other institutional and object contexts, making it far less unique to the Berkeley–Stanford rivalry than the other colors. It is less clear why there is no difference in preference for Berkeley blue. One plausible explanation is that the Berkeley–Stanford rivalry may be asymmetrical. If Berkeley and Stanford students are equally positive about their own school but Berkeley students are more strongly anti-Stanford than Stanford students are anti-Berkeley, then the EVT would predict that the difference in preferences between the two student groups would be greater for Stanford red than for Berkeley blue. Indeed, Berkeley and Stanford students rated their levels of school spirit for their own university about equally (6.95 and 6.85, respectively; t < 1), but Berkeley students rated themselves as significantly more invested in the rivalry than did Stanford studentsFootnote 3 [4.95 and 4.07, respectively; t(100) = 1.82, p < .05, η2 = .03].
We also correlated Berkeley and Stanford students’ school spirit ratings with their preference for each of the four university colors (see Fig. 1b). Although not all of the correlations between spirit and individual color preference were statistically significant, seven out of the eight were in the predicted direction, which is significant in a sign test (p = .04). Among Berkeley students, the correlations between school spirit and preference for Berkeley blue and Berkeley gold were both positive, although only the latter was reliable (r = +.10, p = .23, and r = +.27, p < .05, respectively), whereas the correlation between Berkeley spirit and preference for Stanford red was reliably negative (r = –.31, p < .01). Surprisingly, preference for Stanford white actually increased with Berkeley spirit (r = +.30, p = .04, two-tailed), perhaps because Berkeley athletes often play in mainly white uniforms. This single reversal of the EVT predictions, therefore, has a plausible post-hoc explanation. Among Stanford students, the correlations between school spirit and preference for Stanford red and Stanford white were both positive, although only the latter was reliable (r = +.10, p = .25, and r = +.32, p < .05, respectively), whereas the correlations between Stanford spirit and preference for Berkeley blue and Berkeley gold were both negative, although not reliably so (r = –.06, p = .34, and r = –.16, p = .15, respectively). The low negative correlations may be due to Stanford students’ lower investment in the Berkeley–Stanford rivalry (see above).
We tested how preferences for school colors generalize to similar colors by comparing them to Berkeley and Stanford students’ preferences for the BCP colors that were most similar to the university colors. In general, the correlations were less extreme for these BCP colors than for the corresponding university colors, but in the same direction: BCP dark red (Berkeley students, r = –.28; Stanford students, r = +.10) versus Stanford red (Berkeley students, r = –.31; Stanford students, r = +.24), and BCP saturated yellow (Berkeley students, r = +.12; Stanford students, r = –.11) versus Berkeley gold (Berkeley students, r = +.27; Stanford students, r = –.06). These results suggest that the preference effects due to school spirit generalize to similar colors that would likely be given the same linguistic description (e.g., “dark red” or “vivid yellow”), but that this is not a strong effect.