1. Introduction
Research has shown that the choice to buy a new vehicle is based on several factors such as brand value and the visual perception of exterior and interior features [
1,
2]. Among visual characteristics, the color of the vehicle seems to play an important role in customers’ buying decisions [
3,
4,
5,
6,
7]. From a psychological and applied point of view, the literature on color perception has a long tradition and a broad field of approaches (e.g., [
8,
9,
10,
11,
12,
13,
14,
15,
16,
17,
18]). Research has demonstrated that human color preferences are classifiable into three types: phenomenological (i.e., experience-based), biological (i.e., neural activity to distinct colors), and ecological (i.e., affective responses to colors) [
19,
20]. Furthermore, according to the harmony color perspective (e.g., [
21]), individual aesthetic preferences for color combinations rely on different attributes such as the color arrangement, proximity, similarity, and familiarity that, altogether, produce a pleasing and satisfying effect [
21,
22]. This is of crucial importance considering that the aesthetic quality of a product influences consumer attitudes and is a determinant factor of a product’s marketplace success [
23,
24]. Color favors processes of consolidation of objects’ identity [
25] and plays a role in decision-making processes on what customers like and dislike (e.g., [
5]). Consistently, the association of color with an object changes its preference by people [
26]. Color is also a useful cue to distinguish between objects of similar shape and aids the visual segmentation of objects from their backgrounds and the recognition of visual scenes (e.g., [
27]).
In the automotive field, colors drive the positive experience of a vehicle and increase its perceived quality (PQ) [
28,
29]. PQ does not only refer to the customer’s subjective evaluation of a vehicle or brand value [
30,
31,
32]; it rather embraces aspects such as the aesthetic and functional attributes in satisfying customers’ needs [
33,
34], the quality and reputation of the product [
35,
36] related to the purpose of the purchase, the alternatives in the market, users’ expectations, and previous experience [
30]. Evidence has shown positive and negative associations of colors, e.g., it has been shown that the most preferred colors are white, gray, black, and red as compared to others [
6,
28,
37] and that color repetition and harmony principles can foster the perception of a pleasant interior car ambience [
2,
29,
38]. In this perspective, Wagner and colleagues [
2] aimed at identifying patterns in color choice of potential car customers by asking the participants to create different vehicle interior designs, after which they compared the most and least preferred color compositions. The results showed that the most preferred colors were brown and beige, while the least preferred was gray.
Therefore, although the literature has addressed color perception in the automotive field, to our knowledge, no study has investigated whether the perception of the car’s exterior color could influence the PQ of the interior colors [
1,
6,
18,
28,
29].
Here we aimed at understanding whether and to what extent different color combinations of cars’ exterior/interior sections affect users’ PQ. Specifically, we wondered whether the PQ of a car interior is affected after visually exploring its exterior. Throughout immersive virtual reality (IVR) simulations, participants were asked to visually explore an unbranded car presented in different exterior/interior color combinations (e.g., same color: white exterior–white interior; different colors: white exterior–black interior, etc.) and rate its PQ with an ad hoc 6-item questionnaire recording the following aspects of the interior car ambience: (a) comfort; (b) pleasantness; (c) quality; (d) originality; and (e) efficacy.
During the visual exploration, eye-tracking technology was used. Several psychology and neuroscience studies have recorded eye movement to understand the visual, cognitive, attentional, and motivational aspects of human performance [
39,
40]. Evidence has been reported that the vehicle purchase decision can be attributed to color after a short visual exploration (up to about 90 s) [
41]. This implies that eye-tracking can be a useful tool to assess individuals’ behavior and to interpret their responses to different visual stimuli [
42].
Here, the eye-tracking patterns, indexed by fixation duration (i.e., the amount of time spent looking at a visual target), represent a reliable measure of individual differences in attentional and motivational processes [
43,
44]. Therefore, we expected the visual exploration to be different depending on the color combinations of the car’s exterior and interior parts. Specifically, based on color harmony principles and attentional/motivational mechanisms, we put forward the following hypotheses:
- (1)
A shorter fixation duration when exterior and interior color combinations are perceived as familiar (e.g., black interiors) or similar (e.g., same color combinations).
- (2)
A longer fixation duration for unfamiliar or unexpected color combinations (e.g., color combinations with red). We supposed that new or unfamiliar stimuli may draw more attention than familiar or expected ones [
45,
46,
47].
- (3)
Subjective PQ evaluations have a role in individuals’ attentional behavior (e.g., eye-tracking patterns).
Moreover, due to male/female differences in automotive color preference, gender differences were also investigated [
16].
Finally, the discussion of the main findings, practical implications tied to the automotive field, limitations, and future studies are presented.
4. Discussion
The purpose of this study was to investigate whether the perceived color of a car’s exterior could influence the perceived quality (PQ) of its interior. To this end, we exploited immersive virtual reality (IVR) simulations of an unbranded car by integrating eye-tracking technology and explicit PQ subjective measures.
As regards the eye-tracking data, partially in line with our hypotheses, the results showed that attentional processes towards color aesthetic features of car interiors can be different after visually exploring its exteriors. Indeed, with respect to all other conditions, when the white and red exteriors were combined with gray and black interiors, the fixation duration was longer for the gray than the black color. As we expected, the color combinations with red received more attention presumably because they were less familiar (or unexpected). This result would seem to be consistent with attentional processing perspectives on shifting attention from a familiar (or known) to an unfamiliar (or unexpected) visual target [
45,
46,
47]. However, participants also showed the same eye-tracking patterns with color combinations that should be considered more familiar (i.e., color combinations with white). Presumably this could depend on subjective color preferences (i.e. what people like or dislike) [
5].
As regards the subjective PQ evaluations, the regression analysis showed that individual preferences for color combinations have a role in allocating attentional resources to the vehicle. Indeed, as the negative evaluations for car appearance increased, the fixation duration on car interiors also increased. In particular, when the interior sections were presented in black (after seeing the white exterior) and gray (after seeing the gray exterior), these were perceived as being of poor quality and were fixed on longer; when the interior sections were presented in black (after seeing the black and gray exteriors) and gray (after seeing the black exterior), these were perceived as disturbing and fixed on longer; when the interior sections were presented in gray (after seeing the black and red exterior) and red (after seeing the red exterior), these were perceived as uncomfortable and fixed on longer; when the interior sections were presented in black (after seeing the gray exteriors), these were perceived as banal and fixed on longer. A possible explanation for these mixed results could be given in the light of color harmony perspective [
21]. As stated before, individual aesthetic preferences for color combinations rely on different attributes that, taken together, give a pleasing or satisfying effect; however, which combinations give rise to the pleasing effect is still an open question, as the perception of color harmony changes from individual to individual, from culture to culture, and even over time [
60]. Thus, presumably here, some exterior/interior combinations more than others were perceived as not harmonious or pleasant.
5. Conclusions
From a practical point of view, these results seem to suggest that, in the automotive field, the aesthetics of color combinations for the exterior and interior car sections may influence the way the vehicle attracts potential customers’ attention and their further appreciation.
More importantly, the results seem to indicate that subjective preferences regarding the aesthetic qualities of car color combinations play a role in attention and motivational processes of the potential customer. This aspect is crucial considering that products perceived in a pleasant way work better and affect users’ purchase decisions [
61]. However, we recognize that the present study had limitations which are discussed below (
Section 5.1).
5.1. Limitations and Future Studies
We acknowledge that the results presented are preliminary and lack conclusive guidelines in the automotive field as to how exterior colors influence the car’s PQ (especially its interior) and the behavior of potential customers. Future research is needed to clarify and further explore the relationship between colors, perceived quality, and attentional processes as well buying decisions. The current study relied on a single explicit measure evaluating the PQ, tapping into a few aspects (i.e., comfort, pleasantness, efficacy, originality, and quality) of the subjective experience with the vehicle. It would be interesting to include more comprehensive measures of subjective aesthetic preferences and also to consider measures of whether and to what extent certain color combinations are (or are not) perceived as harmonious. For example, the data presented here does not allow us to discern whether certain color combinations are unpleasant per se or because they do not fulfil their purpose (e.g., to look at a high-quality, comfortable, original or reliable vehicle). Furthermore, other critical aspects could be represented by the small sample size (including only undergraduate students) and the fact that the research did not take into account the possible influence of different car brands and designs, as well as other visual characteristics (textures, color patterns, and materials) on PQ and attentional processes.