The Cross-Zone Navigation and Signage Systems for Combatting Cybersickness and Disorientation in Middle-Aged and Older People within a 3D Virtual Store

Abstract

With the maturation and popularization of 3D virtual reality (3D VR) technology, various corporations have employed 3D VR animations to enrich the experience of visiting a store and change how products are presented. Because middle-aged and older adults have weaker mobility and perception abilities, their behaviors in 3D virtual stores may differ entirely from those of younger age groups. This study aimed to develop a cross-zone navigation system and a signage system for 3D virtual retail stores to provide middle-aged and older consumers with high-efficiency navigation for finding products quickly. Additionally, the effect of the systems on combating perceptual conflict was assessed to confirm the practicability of 3D virtual retail shopping. The results revealed that the cross-zone navigation system effectively assisted participants in searching for their desired products. Additionally, the cybersickness score (SSQ) of the cross-zone navigation system group was significantly lower than that of the map-based navigation system group. The participants who used both the cross-zone navigation system and the signage system exhibited the lowest perceptual conflict scores. Therefore, this study provides references for developing a novel navigation system for 3D virtual retail stores (i.e., a cross-zone navigation system with signage).

1. Introduction

The rapid development of the internet has dramatically changed consumers’ shopping styles and has increased their time online. It has prompted corporations to adopt the internet as an essential medium for displaying products. E-commerce websites are the most representative example of this online trend. In addition to driving the transformation of the corporate operational model, this trend has changed consumers’ purchasing behavior [1]. With the maturation and popularization of 3D virtual reality (3D VR) technology, various corporations have employed 3D VR animations to enrich the experience of visiting a store and change how products are presented. These animations enable consumers to interact with products from various angles by magnifying, minimizing, and spinning 3D products. Therefore, 3D virtual store applications have gained increasing popularity online. Spark Inc. opened its first 3D virtual store in New Zealand in 2020 to take advantage of market opportunities [2]. Altarteer and Charissis (2019) [3] reported that the sense of presence and the flexibility of 3D VR scenarios increased consumers’ acceptance and enjoyment of 3D VR stores. The interaction and visual space cues of 3D VR stores enhance consumers’ perceived information and fun, thereby strengthening their consumption intention [4]. Because of their weak mobility and spatial perception abilities, the middle-aged and older populations’ online behaviors are entirely different from that of the younger population. 3D virtual stores designed for the younger population may cause middle-aged and older populations to experience spatial disorientation and spatial conflict. Therefore, a 3D virtual store must be well-designed for the middle-aged and older populations.

1.1. Problems Related to Spatial Perception

In 3D VR applications, VR screens provide users with a unique visual experience. The use of small screens to display visuals enables users to generate their visual centers and intuitively operate the virtual interface by drawing from their personal experiences. Although users can turn, move, raise, or lower their heads to adjust their vision in the VR environment, a smaller field of view affects their spatial perception ability [5]. Therefore, studies have investigated users’ spatial abilities and the visual perception problems caused by interacting with VR environments. Spatial orientation refers to users’ ability to discern and maintain their positions relative to other positions in a spatial environment [6]. In 3D VR, a user’s line of sight may be obstructed by signs, walls, or buildings. In such cases, users’ spatial orientation determines the smoothness of their positioning and the navigation process.

Spatial orientation determines one’s ability to obtain and use spatial information. It includes spatial perception abilities and abilities related to operating and controlling space. In investigations of problems related to spatial perception, scholars have discovered that spatial perception ability determines users’ ability to assess their position and direction and quickly arrive at their destination. When users lose their spatial perception ability, they may experience a loss of direction [7]. Cognitive psychology studies have revealed that the human field of vision is approximately 130° vertically and 180° horizontally, and the central 120° is where stereo vision lies. However, in a VR environment on a flat-panel display, the first-person view is only 30° horizontally [8]. Limitations in field of view are critical factors that influence the amount of information users can acquire from a given space [9]. Middle-aged and older consumers generally have weaker spatial orientation abilities [10]. Therefore, VR spaces without large-scale reference coordinates representing spatial directions and 3D virtual stores with complex spatial allocation and product displays may cause middle-aged and older consumers to experience problems related to spatial perception.

1.2. Perceptual Conflict

In a 3D VR environment, the method of operating the equipment, the properties of the system, and problems related to the user may cause some users to experience motion sickness or similar symptoms of discomfort. These symptoms are known as “cybersickness” [11]. Cybersickness symptoms include eye fatigue, headache, paleness, sweating, dry mouth, bloating, a loss of directional awareness, dizziness, ataxia, nausea, and vomiting. These symptoms may arise from perceptual conflicts caused by the differences between the perceived information and the expected experience or the users losing their sense of balance. A study revealed that prolonged exposure to 3D VR environments may result in cybersickness [12]. Therefore, 3D VR environments are directly related to the cause of cybersickness. When middle-aged or older adults enter 3D virtual stores to engage in online shopping, a poor navigation system may cause them to experience spatial disorientation and misrecognition. This may cause them to experience perceptual conflicts and quit using 3D virtual stores. Therefore, 3D virtual stores should be designed to reduce such perceptual conflicts and create an adequate shopping navigation system.

1.3. Searching Ability Problems

Physical stores (e.g., retail stores) that require overly complicated processes to search for products may cause consumers to lose their patience. One study proposed that effective spatial layouts and signage may reduce consumers’ time searching for products [13]. Accordingly, finding products within the shortest amount of time possible in 3D virtual stores is the primary concern of consumers. Levy and Weitz (2012) [14] compiled three product layouts in physical retail stores: grid, freeform, and boutique. The grid layout is designed for rapid shopping and enables consumers to find products quickly. This layout sorts products by category onto two parallel shelves in each aisle, which allows consumers to navigate the shop and search for products promptly. Most retail stores employ this layout [15]. Upon entering stores with this layout, consumers must select a specific aisle and search for products on the shelves. After consumers choose their products and check out, they proceed to the exit. This process requires a good navigation system; otherwise, it can easily cause consumers to lose their way and have trouble searching for products. This problem is also present in 3D virtual retail stores. Because of the screen size and the limited field of vision in VR environments, signage in these environments may be insufficient to ensure that consumers quickly and effectively find products in a complex retail store environment. Therefore, this study aims to facilitate this process, allowing consumers to quickly and effectively find products.

Additionally, this study attempts to increase middle-aged and older consumers’ acceptance of online 3D virtual retail stores and their efficiency in shopping and to accelerate the development of 3D virtual retail store applications. Accordingly, this study designs a cross-zone navigation system and a signage system for 3D virtual retail stores to provide middle-aged and older consumers with high-efficiency navigation and prevent spatial disorientation. Additionally, the effect of the systems on combating perceptual conflicts is assessed to increase the practicability of 3D virtual retail shopping. Therefore, the study makes the following several major contributions:

• Establishing a grid layout of a 3D virtual retail store for conducting an experiment;
• Applying 3D technology to construct a shopping navigation system with a cross-zone mode and a map mode in a 3D virtual retail store;
• Applying visual characteristics to develop a signage system for middle-aged and older consumers within a 3D virtual retail store;
• Using the experimental design method to evaluate the effect of a cross-regional navigation system and signage system on the improvement in spatial ability and reduction in cybersickness of middle-aged and elderly consumers within a 3D virtual store.

2. Materials and Methods

2.1. Layout of the 3D Virtual Retail Store

Here, a 3D virtual retail store was designed for selling daily necessities. The 3D retail store prototype featured a grid layout. The interior of the shop and the products were displayed using 3D Max. First, the surface textures and structures were designed in 3D Max. Second, the software output the 3D models of the products and the interior of the VR retail store. There were 23 shelves and over 150 products (Figure 1).

2.2. Design of the Navigation System

When consumers enter unfamiliar, large-scale buildings, such as shopping centers, airports, or exhibition halls, they can become lost because of the size of the area, poor signal arrangements, or a complex layout. This can be prevented by providing consumers with maps or navigational systems. Some movies depict characters or spaceships passing through portals and directly hopping from one space to another, which is commonly referred to as “space-jumping technology”. Although this technology has yet to be developed, space jumping is possible in VR. By adapting the concept of space-jumping technology, this study designed a cross-zone navigation system (Figure 2). Figure 3 shows the cross-zone navigation system execution process. Consumers first identified the product exhibition sections displayed on a simulated tablet computer fixed on a trolley; then, they could select the desired section and click. If there were purchased items in the trolley, the system grouped them first. According to the desired section, the system selected the coordinates of the desired section from the prebuilt spatial coordinate file. At the same time, the grouped trolley was cut, then the screen was moved to the coordinate position of the desired section, and the cut trolley was pasted in the new space. Additionally, for comparison in the experiment, conventional map-based navigation was constructed (Figure 4).

2.3. Signage Design

A study indicated that sigs in VR retail stores should consist of symbolic, textual, and colorful visual elements [16]. Combining these elements may enhance the impression that a display makes on consumers. Additionally, signs indicating the position of products in retail stores allow consumers to determine their position relative to a product. This process might make consumers interested in products, which can increase sales. Signs in 3D virtual retail stores designed based on this principle can provide middle-aged and older consumers with helpful information to navigate a store, find products, and prevent spatial disorientation and cybersickness. This study employed the following principles to design a signage system for a 3D virtual retail store:

• Indexicality: assisting consumers in finding a path or position in the environment.
• Navigability: providing comprehensive spatial and geographic data for consumers to find items and make decisions.
• Discriminability: assisting consumers in identifying sections and other features of the environment.
• Directionality: providing reference points for consumers to determine their position in a 3D virtual retail store.

Individuals in unfamiliar environments develop spatial and directional perception through repeated trial and error correction processes, during which they construct a comprehensive spatial perception map. Therefore, using a map to display pathways can effectively reduce the time required for users to formulate a spatial perception map. Therefore, this study determined whether this system could prevent spatial disorientation in 3D virtual retail stores. First, we created some signpost maps and placed them at the entrance and at each store corner to enable consumers to navigate the sections (Figure 5a). Additionally, the color of each section in the store corresponded to a section on the map to ensure that the signs were recognizable and that the store was easily navigable. Signs for each section were also hung above each shelf to provide indexicality. Finally, landmarks were placed at forks and the corners of each aisle (Figure 5b) to provide references for consumers to confirm their locations. The signage system for the 3D virtual retail store was created to assist middle-aged and older consumers in developing a spatial perception map and to prevent spatial disorientation.

2.4. Research Hypotheses

Farran et al. (2017) [17] revealed that the human brain constructs spatial maps consisting of three knowledge layers: landmarks, paths, and layouts. These maps contain information regarding distance and direction. When entering an unfamiliar environment, individuals first acquire landmark knowledge and accumulate and form path knowledge. Complete path knowledge aids in constructing a spatial layout. The navigation and signage systems in the 3D virtual retail store were designed to allow consumers to quickly construct spatial knowledge and develop spatial perception ability. Accordingly, we proposed the following hypotheses:

Hypothesis 1 (H1).

Cross-zone navigation systems have significantly better effects on spatial perception ability than traditional map-based navigation systems for middle-aged and older adults.

Hypothesis 2 (H2).

The use of a signage system significantly affects the spatial perception ability of middle-aged and older adults.

Studies have indicated an absolute relationship between 3D VR environments and the occurrence of cybersickness [11,12]. When middle-aged or older adults visit 3D virtual retail stores to shop online, poorly designed navigation systems may cause the consumer to experience spatial disorientation and perceptual conflict from improperly operating the VR environment. Poor exposure to the VR environment may cause middle-aged and older consumers to reject the VR environment and leave the store. Therefore, this study determined whether the cross-zone navigation system and the signage system effectively reduced the occurrence of perceptual conflict and proposed the following hypotheses:

Hypothesis 3 (H3).

Cross-zone navigation systems exert significantly better effects on perceptual conflict than traditional map-based navigation systems for middle-aged and older adults.

Hypothesis 4 (H4).

The use of a signage system significantly reduces perceptual conflict for middle-aged and older adults.

The development of spatial perception ability may prevent perceptual conflict; additionally, perceptual conflict may inhibit the development of spatial perception ability. This suggests that better spatial perception ability reduces the risk of perceptual conflict and that perceptual conflict affects the development of spatial perception ability. To determine whether spatial perception ability has a stronger effect on perceptual conflict than on spatial perception ability, the following hypotheses were proposed:

Hypothesis 5 (H5).

Spatial perception ability has a significant effect on preventing perceptual conflict.

Hypothesis 6 (H6).

Perceptual conflict has a significantly negative effect on spatial perception ability.

2.5. Experimental Design

2.5.1. Independent Variables

A.

Navigation factors: evaluating the effect of the navigation system on spatial perception ability and perceptual conflict in middle-aged and older consumers visiting a 3D virtual retail store. These factors were divided into two levels, namely, the cross-zone navigation system and the map navigation system, based on the system’s structure.

B.

Sign factors: evaluating the effect of the signage system on the spatial perception ability of and perceptual conflict in middle-aged and older consumers visiting a 3D virtual retail store. These factors were divided into two levels: with and without signs.

2.5.2. Dependent Variables

A.

Spatial perception ability: This variable was used to determine whether the participants had spatial orientation and position cognitive abilities with different navigation systems and with or without the signage system in the 3D virtual retail store. These skills were evaluated through a spatial perception ability evaluation map. The participants were requested to identify the positions of specific products on the map and were awarded 1 point for each correct answer (maximum score of 10 points). The sum of the scores was used as the evaluation data to determine whether the navigation and signage systems assisted middle-aged and older adults in developing spatial perception ability in the 3D virtual retail store.

B.

Perceptual conflict: We performed a subjective evaluation of the participants’ psychological state. Hemingway (1942) [18] proposed different scoring standards for motion sickness symptoms. These standards measured 25–30 symptoms in patients. Kennedy et al. (1993) [19] redesigned a motion sickness questionnaire to evaluate cybersickness symptoms and developed the simulator sickness questionnaire (SSQ). This questionnaire comprises 16 symptom evaluation items and divides the results into three categories: oculomotor, disorientation, and nausea. The SSQ has been applied in multiple studies [20,21,22,23,24]. This study employed the SSQ to evaluate cybersickness symptoms.

2.5.3. Participants

In this study, a two-factor, two-level random experiment was conducted. A total of 24 middle-aged and older participants between 50 and 70 years old were recruited (mean age: 61.6 years; standard deviation: 3.8 years). All participants passed eyesight and computer operation tests to reduce experimental variance caused by individual differences. During the experiment, one-half of the 24 participants were randomly selected and assigned to the cross-zone navigation system, and the other half was assigned to the map navigation system. Each half was then randomly divided into two groups: one group was assigned to the signage system, and the other did not have the signage system.

2.5.4. Experimental Procedure

Before the experiment, the authors administered the SSQ to determine whether the participants had experienced cybersickness. Each participant was then given a manual to operate the 3D virtual retail store, and the authors guided the participants and ensured that they understood the system’s operations. After the 3D virtual retail store environment was introduced, each participant was given a shopping list with ten products to purchase, two of which were unavailable in the store. When the participants confirmed a target product from the store, they marked the product on the shopping list. For every two products that participants found, they were asked to identify their position on the spatial perception ability evaluation map. The question was repeated until the participants completed the shopping task. After the experiment ended, the SSQ was administered to the participants again.

2.6. Statistical Analysis Method

The independent variables (i.e., navigation system and signage system) were considered nominal. To analyze their effect on the dependent variables (i.e., spatial perception ability and perceptual conflict), we performed a two-way ANOVA and a comparative analysis of the impact.

3. Results and Discussion

3.1. Effect of the Navigation System and Signage System on Spatial Perception Ability

In terms of spatial perception ability, the two-way ANOVA results indicated that the effect of the navigation system on the participants’ spatial perception ability was significantly different (F = 11.598, p = 0.003). The effect of the signage systems on the participants’ spatial perception ability was also significantly different (F = 27.268, p = 0.000). The interaction between the navigation system and the signage system was significant (F = 4.175, p = 0.005). To understand whether the effect of the cross-zone navigation system was better than that of the map navigation system on spatial perception ability, a t-test was performed. The results indicated that the map navigation system enabled participants to develop a more vital spatial perception ability than the cross-zone navigation system (t = 4.103, p = 0.001) (Figure 6). Possible reasons were that, by using the cross-zone navigation system, the participants could search for sections and select a section from the catalog on the tablet computer and then directly jump to the target section. Participants lacked complete browsing of the 3D virtual store, and the completeness of the spatial map was also relatively weak. Therefore, the spatial knowledge experienced by the participants was relatively low. Conversely, the map navigation system was more effective in enabling the participants to develop an understanding of the 3D virtual store space while searching for more products. By referring to the map, a participant could effectively acquire knowledge of the space. Therefore,

• H1 was rejected.

Figure 6. Spatial perception ability scores for map-based navigation and cross-zone navigation groups.

Figure 6. Spatial perception ability scores for map-based navigation and cross-zone navigation groups.

The groups using the signage system exhibited significantly higher spatial perception ability scores than those without the signage system (t = 5.702, p = 0.000) (Figure 7). This result suggests that the participants referred to the signposts to understand the store’s layout. The signs for each section were color-coded to match the colors on the signposts, providing the participants with comprehensive spatial information (i.e., navigability) and the environmental characteristics of each section (i.e., discriminable). Additionally, signs were hung above each section to allow the participants to determine their positions and search for pathways (i.e., indexability). Landmarks were placed at the store’s forks and corners to give the participants a point of reference and enable them to develop a more comprehensive spatial map (i.e., directionality). The signage system helped the participants develop a spatial perception map, strengthening their spatial perception ability. Therefore,

• H2 was accepted.

Figure 7. Spatial perception ability scores of groups without and with signage.

Figure 7. Spatial perception ability scores of groups without and with signage.

3.2. Effect of the Navigation System and Signage System on Perceptual Conflict

This study employed the SSQ and measured the participants’ performances in three dimensions, namely, oculomotor, disorientation, and nausea, before and after the experiment to determine whether they exhibited the main symptoms of cybersickness. The results indicated that the SSQ scores of the middle-aged and older participants increased after the experiment; their mean scores increased by 1.465 points (t = 4.776, p = 0.000). Therefore, after browsing the 3D virtual store for a while, some cybersickness symptoms were induced in the middle-aged and older participants.

Additionally, the two-way ANOVA results indicated that the effect of the navigation system on the participants’ perceptual conflict was significantly different (F = 14.241, p = 0.001). The effect of the signage system on the participants’ perceptual conflict was not significantly different (F = 10.696, p = 0.003). The interaction between the navigation system and the signage system was also not significant (F = 1.582, p = 0.223) (Figure 8). To understand whether the effect of the cross-zone navigation system was better than that of the map navigation system on perceptual conflict, a t-test was performed. The results indicated that the cybersickness scores of the cross-zone navigation group were significantly lower than those of the map navigation group; the mean score was 1.402 points lower (t = −3.044, p = 0.006). The participants in the cross-zone navigation system group from the catalog directly jumped to the target section, quickly found the required products, and avoided having to pass through the aisles multiple times to search for products. The system decreased their exposure to the VR environment, preventing them from experiencing spatial disorientation and perceptual conflict in the 3D virtual store. The participants in the map navigation group were required to repeatedly pass through the aisles in the 3D virtual store. Although this enabled them to develop their spatial perception ability, it also increased their risk of perceptual conflict. The cross-zone navigation system guided the participants to quickly reach the desired positions of the target products, thereby preventing spatial disorientation and other problems caused by unfamiliarity with the 3D VR environment. Additionally, if the participants lost their spatial orientation from improperly operating the system, they could quickly correct their spatial position by using the catalog on the tablet computer. This was one significant advantage of the cross-zone navigation system. Therefore,

• H3 was accepted.

Figure 8. SSQ scores for map-based navigation and cross-zone navigation groups.

Figure 8. SSQ scores for map-based navigation and cross-zone navigation groups.

In signage, the results showed a significant difference between with and without the signage system on perceptual conflict. A t-test was performed. The results indicated that the cybersickness scores of the group in the 3D virtual retail store with signage were significantly lower than those without signage; the mean score was 1.216 points lower (t = −2.862, p = 0.007) (Figure 9). The reason may be that the purpose of the signage system was to inform the participants of their position and destination and to provide details regarding target products. Additionally, the signs prevented the participants from idling, taking wrong turns, and straying from the correct path. Hu et al. (1997) [25] found that sickness symptoms were shown to increase in participants exposed to a drum rotating at 60°/s around its vertical axis. Muller et al. (1990) [26] reported that rotation speeds ranging from 10°/s to 200°/s around the lateral axis of an optokinetic projection of random dots resulted in a vection sensation after 3–8 s of exposure. Therefore, a virtual scene’s incorrect movement might be a critical factor inducing cybersickness in a 3D virtual retail store. The signage system could reduce the wayfinding time and the excessive manipulation of the participants (e.g., fast movement, quick rotation). That is why the signage system was as effective in reducing cybersickness as the situation without a signage system. Therefore,

• H4 was accepted.

Figure 9. SSQ scores of groups without and with signage.

Figure 9. SSQ scores of groups without and with signage.

3.3. Analysis of the Mutual Effect between Navigation System and Signage System

An analysis of the effect of the navigation system and the signage system on the participants’ behavior revealed that the map-based navigation system had a more substantial effect on the participants’ spatial perception ability than the cross-zone navigation system. However, regarding perceptual conflict, the cybersickness scores for the cross-zone navigation system group were lower than those of the map-based navigation system group. The group that used both the map-based navigation and signage systems had the highest spatial perception scores (Figure 10). The group that used both the cross-zone navigation and signage systems had the lowest SSQ scores (Figure 11).

Howes et al. (2001) [27] found that, in 3D VR environments, a user’s line of sight may be blocked by a sign, a wall, or a building. In this case, users must turn, move, raise, or lower their heads to adjust their fields of vision, which may reduce their spatial perception. Therefore, a complex arrangement of shelves and layouts of the products in 3D virtual retail stores may cause middle-aged and older consumers to experience spatial disorientation. The results indicated that the combination of the map-based navigation system and the signage system provided more spatial information to the participants, enabled them to develop spatial perception maps effectively, and substantially strengthened their spatial perception abilities. Because these participants had a more vital spatial perception ability, they could quickly determine their locations and directions and move to targets. However, the combination did not help much in reducing the occurrence of cybersickness.

The cross-zone navigation system in this study enabled middle-aged and older participants to move quickly to the position of a desired product. It prevented spatial disorientation and other problems from unfamiliar 3D VR spaces. Although the spatial map was incomplete, the signage system linkage could improve the spatial perception ability. The signage system consisted of color-coded sections and signs to increase the navigability and discriminability of the store [28]. Additionally, landmarks were placed in specific locations to give the participants a redundant code. Participants’ spatial disorientation decreased because of the advantages of fast navigation and precise positioning of the cross-zone navigation system, as well as the indexicality, navigability, discriminability, and directionality of the signage system. Since participants reached their destinations quickly, cybersickness was reduced efficiently.

3.4. Interaction Effect between Spatial Perception Ability and Perceptual Conflict

In VR environments, spatial perception determines users’ ability to identify their positions and directions and quickly navigate to their destinations. A loss of spatial perception may result in the loss of spatial orientation. It can cause users to improperly position themselves or operate the VR equipment incorrectly, thus increasing their risk of cybersickness. Additionally, users may experience cybersickness symptoms in VR environments, such as eye fatigue, headaches, dry mouth, bloating, and dizziness, after losing their spatial perception ability. This study determined which of the two (spatial perception ability and perceptual conflict) had a more significant influence on the other.

According to the regression analysis results, the influence coefficient of spatial perception ability on perceptual conflict was −0.267, indicating no significance (t = −1.513, p = 0.145). The influence coefficient of perceptual conflict on spatial perception ability was −0.353, indicating no significance (t = −1.513, p = 0.145). Therefore,

• H5 was rejected.
• H6 was rejected.

Although the interaction effect between spatial perception ability and perceptual conflict was insignificant, some issues should be discussed.

First, spatial perception ability negatively affected perceptual conflict; for each point increase in the spatial perception score, the perceptual conflict scores (SSQ) decreased by 0.267 points. Additionally, perceptual conflict also negatively affected spatial perception ability. For each point increase in the perceptual conflict scores (SSQ), the spatial perception ability score decreased by 0.353 points. The results showed that perceptual conflict had a more substantial effect on spatial perception ability. This result indicated that, despite the mutual causal relationship between perceptual conflict and spatial perception ability, the influence through which perceptual conflict affected spatial perception ability was more significant than the influence through which spatial perception ability affected perceptual conflict. This result suggests that, after consumers entered the 3D virtual retail store, feelings of cybersickness due to improper system operation and posture significantly reduced their spatial perception abilities.

Second, in the absence of signage, single map-based navigation was incomplete and challenging for the participants to establish spatial knowledge. As a result, consumers might continue to search back and forth for products due to a lack of landmark knowledge; therefore, cybersickness occurred quickly. Under perception conflict, consumers’ spatial perception ability worsened. As a result, cybersickness became more severe. The result of the vicious cycle made consumers hate 3D virtual stores. Therefore, improving spatial perception ability and reducing cybersickness are critical factors in developing 3D virtual retail stores. Combining cross-zone navigation and signage could achieve this effect.

3.5. Overall Comparative Analysis

This study aimed to develop a cross-zone navigation system and a signage system for 3D virtual retail stores to provide middle-aged and older consumers with high-efficiency navigation for finding products. According to the results of the previous discussion, the group that used both the map-based navigation system and the signage system had the highest spatial perception scores, but the group that used both the cross-zone navigation and signage systems had the lowest SSQ scores. Therefore, there was a substantial effect of combating cybersickness on the combined cross-zone navigation–signage system. In the SSQ analysis, there were three distinct symptom clusters labeled oculomotor (O; eyestrain, difficulty focusing, blurred vision, headache), disorientation (D; dizziness, vertigo), and nausea (N; nausea, stomach awareness, increased salivation, burping) [19]. To further understand the effect of the cross-zone navigation system and the signage system on combating different symptoms of SSQ, a comparative study was performed, as shown in Figure 12 and Figure 13. Figure 12 shows that participants’ average SSQ subscores (oculomotor, disorientation, and nausea) increased after the experiment. However, the SSQ subscores of the combination of map-based navigation without signage increased significantly, especially for oculomotor activity. The SSQ subscores of the combination of cross-zone navigation with signage increased insignificantly. In fact, the study of Kennedy et al. (1993) showed that a high oculomotor score was most likely due almost entirely to some property of the visual system. Therefore, as long as an individual is operating in a virtual environment, oculomotor symptoms may inevitably occur. In Figure 13, it can be seen that oculomotor activity increased in different navigation combinations, but the combination of cross-zone navigation with signage had the smallest increase. The scores for disorientation and nausea did not increase. This showed the effectiveness of the cross-zone navigation and signage systems developed in this study in combating cybersickness, especially on the two symptom clusters of disorientation and nausea.

In object-seeking, Figure 14 shows a box-and-whisker plot of object-seeking times for four different system combinations. The results showed a significant difference between the map-based and cross-zone navigation systems (t = 12.957, p = 0.000). The group that used the map-based navigation system with or without a signage system spent more time seeking target objects. Because of exposure to the virtual environment for a long time, these groups could easily induce cybersickness. The cross-zone navigation system assisted the participants in seeking target objects quickly. Shortening the time to seek the object was also the primary reason for reducing the occurrence of cybersickness, as discussed in the previous paragraph. Additionally, there was a significant difference between map-based navigation systems with and without signage (t = 2.905, p = 0.017). It also explained the importance of signage for map navigation.

Finally, in system utilization, Figure 15a shows the CPU and GPU performances when a participant used the map-based navigation–signage system to seek one target object. Figure 15b shows the performance of another participant using the cross-zone navigation-signage system to seek the same object. For the moment of space crossing, the CPU utilization had a peak (Figure 15b red circle in the CPU utilization) in the cross-zone navigation–signage system, but the GPU utilization was lower than the map-based navigation–signage system. The results showed that the cross-zone navigation system required more CPU operations but less GPU utilization for 3D image display.

4. Conclusions

Three-dimensional virtual technology has increased the interactivity of products displayed in online retail stores. This development provides middle-aged and older adults with additional shopping choices. This study attempted to solve problems related to spatial perception ability and perceptual conflict in 3D virtual retail stores. To this end, we developed a cross-zone navigation system and a signage system to equip 3D virtual retail stores with practical consumer navigation functions. The results revealed that the cross-zone navigation system effectively assisted middle-aged and older consumers in searching for their desired products. Additionally, the cybersickness score (SSQ) of the cross-zone navigation system group was significantly lower than that of the map-based navigation system group. The middle-aged and older participants who used both the cross-zone navigation and signage systems exhibited the lowest perceptual conflict scores. This result verified that the combination of the cross-zone navigation system and the signage system successfully strengthened the navigational abilities of middle-aged and older consumers and reduced spatial conflict. Therefore, this study provides a new reference and criteria for the design of navigation and signage systems for 3D virtual retail stores with mainly middle-aged and elderly consumers.

This study constructed a 3D virtual retail store for the experiment. Because the products must be created using 3D modeling, their variety and quantity were limited to hard surfaces and distinct appearances; therefore, the products did not include fresh vegetables, meat, or complex consumer electronics (e.g., keyboards, mouses, and headphones). Because of the researchers’ limited 3D-modeling skills, some products may have appeared rigid and hard to identify. Additionally, the sample size was small because individuals aged between 50 and 70 years old must be willing to participate in the experiment and must pass eyesight and computer operation tests. However, the findings offer valuable ideas for the design of 3D virtual retail stores.