The present study was designed to investigate whether or not the color (either black or white) of the plate would exert a significant influence on how appealing and appetizing three different desserts were rated (prior to consumption), and if the perception of these visual attributes affected the perceived flavor, sweetness intensity and final overall liking of diners in a restaurant setting. While other researchers have focused on the impact of visual cues and the presentation of food on consumers’ acceptance and preference [1, 2, 7], including the estimation of portion size , to date the effect of an extrinsic factor, such as the color of the plate on visual and oral perception of food, has not been studied in any depth . Importantly, this study was performed in an entirely ecologically valid setting (a real restaurant), under natural conditions (that is, using a between-participants design, with participants able to interact and consume their meal at their own pace) and with three different desserts (served in as similar a manner as possible).
The results demonstrate that the color of the plate affected consumers’ perception mainly for the attributes based on visual judgments (liking of the presentation, appetizing and color intensity of the dessert). One limitation to be taken into account when interpreting the results is that although the ratings given for the visual attributes were positively correlated, it could be that there was a halo effect (that is, ratings of appetizing may have overridden ratings of the color intensity and overall liking of the presentation). Although balancing the order of presentation of these attributes in the questionnaire could have ruled out this order effect, it is likely that the diners would have rated these three related attributes in a similar way, regardless of the order of presentation of the questionnaire items.
The attributes of the desserts based on chemosensory qualities of the food stimuli (that is, flavor intensity and sweetness) were affected mainly by the type of dessert served, but the extent to which these attributes were affected depended on the plate (background color) as well. Figures 2-6 demonstrate that Desserts A and C always received higher scores when presented on the white plate, while the opposite was observed for Dessert B. This consistency across the attributes suggests that, by itself, the color of the plate has the potential to elicit a positive appraisal, and even enhance certain sensory qualities of foods. However, this effect depends to a great extent on the food presented, together with many other parameters, such as the context, material of the plate, and congruity between these factors and the food itself [7, 31]. Once again, the similarity in the response patterns among the attributes could have been due to a halo effect between the attributes rated.
In this study, given the complexity of the visual appearance of the desserts (that is, with layers and decorations of different colors and tastes), the results cannot be explained solely in terms of color contrast between the dessert and the plate, since it was Dessert B, the dessert with darker brown-colored tones, that received higher scores when served on the black plate. This result highlights the complex reasons why consumers prefer certain food products and even perceive some attributes as enhanced when served from one container, or background, rather than another . The reason for the Dessert B result could be that the black background elicited a more intense flavor (that is, it evoked this expectation), which resulted in higher attractiveness and appetizing ratings. However, flavor intensity was not significantly affected.
However, the relationship between the visual and taste-related attributes is of greater interest. Regarding color perception, the flavor intensity patterns observed for all the desserts (Figure 4) were similar to the perceived color intensity of the desserts (Figure 3), and the two attributes were highly correlated. Certain sensory dimensions (such as intensity) are processed by several different modalities. Therefore, it would not be surprising if consumers implicitly perceived a food product as more intense when its color(s) is perceived as such .
However, it could be that the desserts simply ‘looked’ better to diners when served on a certain colored plate. Thus, as part of a halo effect, the rest of the ratings (sensory and hedonic) may also have been enhanced . In any case, it has already been widely demonstrated that the visual appearance of food (presented in a certain container, as it usually reaches the consumer or diner) can affect both sensory discriminative and hedonic appraisal [8, 17, 35], whether as part of a halo effect or as a genuine perceptual effect.
Regarding the lunch and dinner sessions, the lunch sessions had natural lighting conditions, while artificial lighting was used for the dinner sessions. These are the usual conditions in which diners eat at a restaurant; therefore, we decided to keep them as natural and realistic as possible. It is important to highlight that the effect of the session (only interaction effects with the color of the plate and only in ratings of visual attributes, as described in Results) could be due to the differences in illumination conditions (note that the order of presentation of the plates was counterbalanced between the sessions).
The results regarding the changes in the sensory attributes of the desserts as a function of the plate color are not as strong as reported in the Piqueras-Fiszman et al. study . This is understandable, since in the context of a real restaurant, the stimuli cannot be perfectly matched for all consumers and the conditions for all of the diners cannot be kept identical (that is, diners may or may not drink while eating, certain diners may eat more rapidly than others, diners may be distracted while eating, and so on) . Consequently, this makes observations hard to analyze and interpret because testing conditions cannot be controlled as strictly as in laboratory conditions and there could be many other intervening factors [36, 37]. In addition, diners engaged in conversation are less likely to pay attention to the presentation of a food (in particular, to the plate). These observations contrast with testing under laboratory conditions, where participants are tested individually and are more focused on the task. However, on the other hand, these results are more ecologically valid and although no generalization can be put forward to suggest which background color is better in terms of flavor for a given food (dessert), the results nevertheless highlight that the color of the plate can exert a significant impact on consumers’ expectations and appraisal of the food, prior and after consumption, despite the complex uncontrolled conditions, which makes obtaining significant results even more challenging.
Therefore, the results could be particularly relevant in situations where plated dishes are presented to diners prior to tasting, such as restaurant websites, social media, food events, pictorial menus and buffets.