People tend to associate colors with specific flavors, establishing color-flavor associations. Moreover, people can generate flavor expectations about foods and beverages based on colors. Recent research has shown that participants can generate color expectations about packaged food based on a flavor label to guide the visual search for this flavor. However, it remains unclear how flavors modulate color processing. Here, we conducted two visual search experiments to address this issue.
In Experiment 1, we used a peristaltic pump to deliver a dose of fruit-flavored beverage or flavorless purified water to the participants’ mouths (see Figure 1), followed by a shaped- based visual search task (see Figure 2). Half of the participants were informed that the strawberry and pineapple flavors were always followed by targets in the associated colors, while the rest of them were informed that the strawberry and pineapple flavors were always followed by targets in the non-associated colors. By contrast, the flavorless water was not predictive of the color of the target. As shown in Figures 3 and 4, compared to the uninformative flavor cue condition, their visual searches were faster when the target appeared in a flavor-associated color (939 ms vs. 1059 ms), F(1, 21) = 30.71, p < 0.001, η2p = 0.59, 95% CI = [-165.39, -75.13], or when the target appeared in a non-associated color but the flavor-associated color was absent from the display (1008 ms vs. 1097 ms), t(21) = 4.39, p < 0.001, Cohen’s d = 0.94, 95% CI = [-131.75, -47.12]. By contrast, the flavor cue did not facilitate visual search if the distractor was presented in the flavor-associated color (1122 ms vs. 1097 ms), t(21) = 0.79, p = 0.44, thus indicative of prioritized attention to this associated color.
Considering that the participants were exposed to the flavor labels when they received their instructions at the beginning of Experiment 1, we conducted Experiment 2 to rule out the possible influence of flavor labels. Experiment 2 was performed with the same methods as in Experiment 1 except for one important difference. The participants were not given information regarding the specific flavors. They were only informed that flavors A and B were always followed by red- and yellow-colored targets, respectively. The flavors were always followed by targets in the associated colors for half of the participants and by non-associated colors for the rest of the participants. We obtained similar result patterns as in Experiment 1. As shown in Figures 5 and 6, compared to the uninformative flavor cue condition, their visual searches were faster when the target appeared in a flavor-associated color (899 ms vs. 1004 ms), F(1, 16) = 33.30, p < 0.001, η2p = 0.66, 95% CI = [-143.37, -66.33], or when the target appeared in a non-associated color but the flavor-associated color was absent from the display (905 ms vs. 991 ms), t(16) = 4.05, p = 0.003, Cohen’s d = 0.57, 95% CI = [-143.66, -29.45]. By contrast, the flavor cue did not facilitate visual search if the distractor was presented in the flavor-associated color (979 ms vs. 991 ms), t(16) = 0.43, p > 0.99.
The results of these two experiments consistently revealed an attentional bias toward flavor-associated colors in the shape-based visual search. These findings show how flavor cues could modulate visual information processing. Our findings provide empirical evidence regarding color-flavor interactions by showing the influence of gustatory cues on visual attention, which allows us to further investigate the underlying mechanisms and neural basis of crossmodal influence in future research.
