3. Current Study
Two intervention approaches that can be performed prior to player interaction with a virtual environment to improve their experience are transitional environment and practice. Findings of previous studies have suggested that these interventions can improve various aspects of user experience, including spatial perception, immersion, and user confidence. VR game tutorials are supposed to be experienced before actual gameplay, offering the opportunity for intervention implementation. In this study, we examined the effects of two practice versions (real-world and virtual-world practice) on players’ spatial perception, game experience, and performance. We also included a control condition that involved no practice.
Of the two interventions, practices are already a common element in game tutorials while transitional environments are relatively new in VR game tutorials. The approach of transitional environment explored in previous studies [
18,
19,
22,
24] required a virtual replica of the users’ real environment (e.g., a laboratory, players’ homes), presenting a substantial, if not impossible, challenge. Our first set of hypotheses is about the effects of practice on spatial perception:
Hypothesis 1.1 (H1.1). For those who have received virtual-world practice, their spatial perception before gameplay is better than that of players without practice.
Hypothesis 1.2 (H1.2). For those who have received real-world practice, their spatial perception before gameplay is better than that of players without practice.
Additionally, players are expected to perform better after they have received practice.
Hypothesis 2.1 (H2.1). The game performance of players with virtual-world practice is better than that of players without practice.
Hypothesis 2.2 (H2.2). The game performance of players with real-world practice is better than that of players without practice.
In this study, we took a different approach to transitional environment, examining a real-world replica of a tool and a challenge in the initial part of a VR game. The transitional environment used is real-world practice. Since transitional environments provide support for players to gradually transit from a real environment to a virtual environment, replicating a real room provides an environment “in between” the origin (i.e., the real world) and the destination (i.e., the virtual world). An environment similar to the virtual world instead of the real world, by extension, should also serve as a transitional environment as long as the environment is deemed to be in between.
Although an exact opposite of the idea of transitional environment explored in the previous studies should be a physical replica of a virtual environment (e.g., a virtual room) in the real world, it would be costly or impractical for the case of VR games, where most players enjoy their VR games in their homes with limited space. Based on this rationale, we view real-world practice as a superior transitional environment to virtual-world practice, making it more effective at improving spatial perception.
Hypothesis 1.3 (H1.3). For those who have received a real-world practice, their spatial perception before a gameplay is better than that of players who have received a virtual-world practice.
Regarding the impact on game performance, as reality is more familiar to players, it may be a better environment for players to improve their skill than a virtual environment. However, real-world practice is dissimilar to the virtual environment. Similarities between the practice environment and the gameplay environment may give a stronger advantage to virtual-world practice at improving game performance.
Hypothesis 2.3 (H2.3). The game performance of players with virtual-world practice is better than that of players with real-world practice.
Practice helps new players acquire basic skills for a game while improving confidence. It remains unclear which version of practice would give new players higher confidence before gameplay.
The current study focuses on spatial perception within the context of VR games. Spatial perception has been seen as a key aspect in user experience of VR applications. There is limited understanding of the role of spatial perception in relationships between gaming elements and game performance. It would be interesting to examine whether spatial perception influences the effects of practice on game performance. It is possible that spatial perception plays a moderator role in the effects of practices on game performance. Another way to see it is that players’ varying levels of spatial perception may influence the effectiveness of practices on game performance. It is possible because if players have different levels of spatial perception within a virtual environment, the influence of practice on game performance during VR gameplay may be enhanced or compromised.
4. Method
4.1. Study Design
Unlike a previous study that focused on practice that replicated all required tasks in a VR game [
36], the current study focused on real-world practice that only replicated some challenges in a VR game. The independent variable (practice) included three conditions: no practice (control condition), virtual-world practice (VR condition), and real-world practice (reality condition). Comparing the control and reality conditions would inform on the effectiveness of real-world practice compared to no practice, while comparing the reality and VR conditions would inform on the effectiveness of real-world practice by using virtual-world practice as a benchmark.
In total, 67 participants (54 of whom were female) with different levels of gaming experience were recruited on a campus of a government-funded university in Hong Kong. Their ages ranged from 18 to 42 years (mean [M] = 23.8, standard deviation [SD] = 4.3). Among the participants, 44 had experience playing video games with lengths of experience ranging from 2 to 18 years. All of the participants indicated that they had no experience playing VR games. While substantially more females made up the sample, gender differences in spatial perception of a virtual space have not been found previously [
1]. However, the current context is digital gaming. The distribution of the participants’ years of gaming experience across the three conditions is not significantly different (F(2.41) = 0.36, p = 0.70). The participants with no experience playing video games were evenly distributed among the control, VR, and reality conditions (7, 8, and 8, respectively).
4.2. Materials: VR Game and Practices
A VR game, Room on Fire, was designed for this experiment. In the game narrative, the player is trapped in a room that is on fire. The player must extinguish the fire with a water pipe attached to their forehead and can only move their head. A spoon-like tool is attached to the player’s face, allowing the player to catch a ball from a dispenser on their left. The player must catch and transfer the ball to a target container on their right. For every ball that is placed in the target container, the water pipe is activated for 10 seconds, allowing the player to extinguish the fire.
The player must then move their head to control the direction of the water spray and extinguish a portion of the fire. To complete the game, the player must extinguish five fires in the room within 10 minutes. The game was developed using Unity and Oculus Rift DK2. Screenshots of the game are displayed in
Figure 1. Two types of practice tutorials were created for this study: real-world and virtual-world practice. The ball-transfer task in the game was replicated in both versions of the practice tutorial while the task of spraying water from above the player’s head was not replicated.
For the virtual-world practice, a VR program was created (
Figure 2). In the practice program, a spoon-like tool similar to the tool used in the VR game was placed in front of the player’s face in the virtual world. The player controlled the tool by moving their head. A target container and a ball dispenser were placed in locations identical to the game. When the player turned left, a ball was dispensed, allowing the player to transfer the ball to the target container. Each player was given 1 minute to practice.
For the real-world practice, a replica of the spoon-like tool was created (
Figure 3). The tool was attached to a pair of goggles. A small plastic bucket was placed to the right of the participant as a physical replica of the target container. A researcher stood on the left of the participant. During practice, the participant wore the goggles (with the tool attached). Every time the participant turned left, a researcher placed a ball in the spoon-like tool, and the participant was asked to practice transferring balls to the small plastic bucket. The researcher acknowledged for each ball the participant successfully put into the target by saying ‘Hit!’. Each participant was given 1 minute to practice.
The design of the VR game covered both the peripersonal and extrapersonal spaces. The target container for the balls was within hand’s reach (peripersonal space) in the virtual environment [
6]. The fires in the virtual room were situated in locations beyond hand’s reach (extrapersonal space). The two versions of practice only covered the challenge of transferring balls (i.e., the challenge happens in peripersonal space). A reason for this was to resemble the situations where the practice in game tutorials can only cover part of in-game challenges, a common design direction in most digital games. Another reason was to simulate a situation where real-world practice can only replicate a part of a VR game that is feasible in the real world. For this VR game, the ball transferring part was feasible in the real world while the fire extinguishing part was not. The elements in the VR game, including the tool, the design of the room, and the background story, were inspired by previous works [
35,
36].
4.3. Measurements
Three areas corresponding to the hypotheses and research questions were examined: confidence with the game before gameplay, spatial perception, and game performance. Confidence was measured using a 7-point Likert scale survey question: “How confident are you in playing the video game?”
Spatial perception was measured by asking participants to position an object in a physical model of the VR game environment (
Figure 4). Perceptual matching was adopted as a measurement of spatial perception. A simplistic physical model was constructed to resemble the player’s position and the target container in the game.
Figure 4a shows a chair representing the player’s position in the game. The wall behind the chair provides an orientation reference. The cylinder represents the target container.
Figure 4b shows an iPad under the cylinder that is running an application that records the coordinates of the cylinder. The coordinates were recorded every time spatial perception was measured. It was measured twice in the procedure, once before gameplay (after practice, if any) and once after gameplay.
Many methods exist for measuring player performances [
44,
45] and studies have used different measurements for different types of game [
46]. In the current study, game performance was measured with the time spent to complete all the challenges. The less time spent on finishing the challenges, the better the game performance is.
4.4. Procedure
Participants were randomly assigned to the three conditions. The number of participants in the control, reality, and VR conditions were 22, 24, and 21, respectively. When the participants arrived the laboratory, they were briefed on the procedure. After giving written consent, the participants completed a questionnaire regarding background information, such as gender and age.
A PDF document introducing the VR game was shown to the participants after the questionnaire was completed. This introductory document presented the narrative, rules, and gameplay instructions along with some screenshots of the game. Participants in the reality condition then took part in real-world practice (according to
Section 4.2 above); those in the VR condition received virtual-world practice (according to
Section 4.2 above); and those in the control condition did not receive practice. Before playing the game, participants were asked to indicate their confidence with the game with a 7-point Likert scale. To measure their spatial perception, they were also led to a simplified model of the game environment (
Figure 4) and asked to position a cylinder (representing the target container) relative to where the player would be. Participants then put on the VR headset and reminded to explore the game environment. When each participant felt ready, they told the researcher to start the game. Upon finishing the game, each participant removed the VR headset. Participant spatial perception was measured again and finally, they were debriefed. Each session lasted for 45 to 60 min.
5. Results
Table 1 shows a summary of the results.
5.1. Spatial Perception
Since spatial perception was measured twice (before and after gameplay), it was analyzed with a two-way mixed analysis of variance (ANOVA) using a between-subject variable (the study conditions) and a within-subject variable (time of measurement: before and after gameplay). In the two-way mixed ANOVA, there was a significant difference across the three conditions (F (2,64) = 5.01, p < 0.05, η2 = 0.14) and a significant difference across the two time points (F (1,66) = 45.69, p < 0.001, η2 = 0.42). There was no significant interaction between condition and time (F (2,64) = 0.90, p = 0.41).
The main effects of the two variables were deemed significant. In a Bonferroni corrected post hoc analysis, it was found that spatial perception measurements in both reality and VR conditions (averaged across the two time points of measurement) were significantly more accurate than the control condition (both comparisons had p < 0.05). There was no significant difference between the spatial perception measurements of the reality and VR conditions (p = 1.00). In general, the two versions of practice improved player spatial perception. The results indicated a significant main effect across time. The estimated mean of spatial perception improved from 7.91 cm (95% confidence interval (CI): 7.41 cm, 8.41 cm) before gameplay to 5.95 cm (95% CI: 5.45 cm, 6.45 cm) after gameplay.
In a post hoc analysis focusing on the spatial perception before gameplay, a Bonferroni test revealed that the spatial perception of participants before gameplay in the VR condition (M = 7.09 cm, SD = 1.71 cm) was significantly more accurate (p < 0.05) than that of participants in the control condition (M = 8.78 cm, SD = 1.82 cm), supporting H1.1. The test revealed no significant differences for spatial perception between the reality condition (M = 7.85 cm, SD = 2.46 cm) and the control condition, and no significant difference between the VR condition and the reality condition. H1.2 and H1.3 were not supported.
With a focus on the second time point (i.e., after a gameplay), a Bonferroni test revealed that the spatial perception in the reality condition (M = 5.38 cm, SD = 1.69 cm) was significantly more accurate (p < 0.05) than that of participants in the control condition (M = 6.90 cm, SD = 2.42 cm). No significant differences were found between the VR condition (M = 5.56 cm, SD = 2.06 cm) and the control condition, or between the reality condition and the VR condition. The real-world practice showed significant improvement on spatial perception after gameplay.
5.2. Game Performance and Confidence
An ANOVA of game performance indicated significant differences among the participants in the different conditions (F (2,64) = 11.94, p < 0.001, η2 = 0.27). In a post hoc analysis, a Bonferroni test revealed that the game performance of participants in the VR condition (M = 98.33 s, SD = 20.49 s) was significantly higher (p < 0.001) than that of participants in the control condition (M = 137.05 s, SD = 32.56 s). The test also revealed that the game performance of participants in the reality condition (M = 117.46 s, SD = 23.33 s) was significantly higher (p < 0.001) than that of participants in the control condition (p < 0.05). Finally, the test revealed that the game performance of participants in the VR condition was significantly higher than that of participants in the reality condition (p < 0.05). Therefore, H2.1, H2.2, and H2.3 were supported.
An ANOVA of player confidence indicated significant differences among the participants in the different conditions (F (2,64) = 5.02, p < 0.01, η2 = 0.14). In a post hoc analysis, a Bonferroni test revealed that the confidence of participants in the reality condition (M = 5.00, SD = 0.24) was significantly higher (p < 0.01) than that of participants in the control condition (M = 3.91, SD = 0.25). The test also revealed no significant difference in player confidence between the participants in the VR condition (M = 4.48, SD = 0.26) and the participants in the control condition. It revealed no significant difference in player confidence between participants in the VR condition and those in the reality condition. The confidence of participants who received real-world practice was significantly higher than that of those who did not have practice. Therefore, in answer to RQ1, real-world practice was shown to improve player confidence before gameplay.
5.3. Moderation Analysis
To answer RQ2, moderation analysis (to test for any moderating effects of spatial perception before gameplay on the effects of the practice on the game performance) was performed with Model 1 in Hayes’s PROCESS macro version 3.1 for SPSS version 25 [
47]. Practice was coded with the control condition as the reference group. The interaction effect of spatial perception and the practice variable was marginally significant (
p = 0.058). The conditional effects of the two types of practice on game performance vary at different levels of spatial perception.
When the spatial perception was at 5.79 cm (i.e., one SD below the mean), virtual-world practice had a significant effect of on game performance (p < 0.0001) compared to no practice. At this level of spatial perception, the conditional effect of changing from no practice to virtual-world practice was −57.58 seconds (with a 95% CI: −82.81 s, −32.35 s). In other words, virtual-world practice reduced the time to complete the challenges by an average of 57.58 seconds. At this level of spatial perception, the conditional effect of real-world practice on game performance was marginally significant (p = 0.056), which was an average of -24.32 seconds (with a 95% CI: −49.32 s, 0.67 s).
When the spatial perception was at 7.92 cm (i.e., the mean), both virtual-world and real-world practice had significant effect on game performance (p < 0.0001 and p < 0.005, respectively). At this level of spatial perception, the conditional effect of virtual-world practice on game performance was −37.46 seconds (with a 95% CI: −54.59 s, −20.33 s) compared to no practice. The conditional effect of real-world practice on game performance was −23.19 seconds (with a 95% CI: −38.96 s, −7.41 s) compared to no practice.
When the spatial perception was at 10.05 cm (i.e., one SD above the mean), the real-world practice had a significant effect on game performance (p < 0.05). At this level of spatial perception, the conditional effect of real-world practice on game performance was an average of −22.05 seconds (with a 95% CI: −41.21 s, −2.89 s). The conditional effect of virtual-world practice at this level of spatial perception was not found significant (p = 0.19).
To compare the conditional effects between the real-world and virtual-world practice, the moderation analysis was repeated with the reference group changed to the VR condition. The interaction effect of spatial perception and the practice variable remained the same, which was marginally significant (p = 0.058). When the spatial perception was at 5.79 cm (M-SD), the conditional effect of virtual-world practice on game performance was significantly different from that of real-world practice (p < 0.005). At this level of spatial perception, a change from virtual-world practice to real-world practice caused players to spend an average of 33.26 seconds more completing the game (with a 95% CI: 13.83 s, 52.69 s). When the spatial perception was 7.92 cm (M) and 10.05 (M+SD), the conditional effect of virtual-world practice was not significantly different from real-world practice (p = 0.08 and p = 0.72, respectively).
To recap, the conditional effect of virtual-world practice on improving game performance (as compared to no practice) was significant when the spatial perception was at the mean and at a more accurate level (M-SD). The conditional effect of real-world practice on improving game performance was significant when the spatial perception was at the mean and at a less accurate level (M+SD). The difference in the conditional effects between virtual-world practice and real-world practice was deemed significant only when the spatial perception was at a more accurate level (M-SD).
6. Discussion
Regarding spatial perception, H1.1 was supported, indicating virtual-world practice was effective at enhancing players’ spatial perception of the virtual environment before playing a VR game. H1.2 was not supported, indicating that real-world practice provides insignificant enhancement of spatial perception before gameplay. However, according to the results of the mixed ANOVA, participants who received real-world or virtual-world practice had significantly better spatial perception of the virtual environment of the VR game (averaged across time). This suggested that the real-world practice was effective at enhancing spatial perception, but its effect may not be strong enough to be shown as significant immediately following practice. The spatial perception of players with real-world practice may be better after one to two gameplay sessions than those without practice. The time variable in the analysis also showed significant effect, indicating participants had significantly improved spatial perception after their first gameplay session. This is consistent with the previous studies [
28,
29,
30], which stated that practice in (or opportunities to interact with) a virtual environment increase users’ spatial perception of the virtual space.
The hypotheses about the effects of the two practice forms on game performance (i.e., H2.1, H2.2, and H2.3) were supported. Both real-world and virtual-world practice were effective at enhancing players’ game performance. Although the real-world practice happened in a more familiar environment (i.e., the real world), the virtual-world practice was more effective than the real-world practice at improving game performance. On the other hand, the real-world practice was shown to significantly improve player confidence, which was not the case for virtual-world practice. This suggests that having real-world practice may be helpful to the players in areas other than game performance.
Although the moderation analysis of the spatial perception only showed a marginally significant moderator effect on the influence of practices on game performance, the results suggested an interesting pattern, implying that when the spatial perception is the more accurate, the virtual-world practice is more helpful in improving game performance. However, as spatial perception became less accurate, real-world practice became more helpful at improving game performance.
6.1. Theoretical Implications
The results of the current study offer several theoretical implications. Firstly, a game tutorial is a valid opportunity to provide practice to players, improving spatial perception of a VR game’s virtual environment. Even if the practice covers challenges in peripersonal space only while the gameplay involves challenges in peripersonal and extrapersonal spaces, practice still helps improve spatial perception and game performance.
Secondly, real-world practice can be as effective as virtual-world practice and can be better than no practice at all, but the effect becomes significant only if measurements are averaged across time. This contributes to the literature of spatial perception by suggesting that real-world practice can be adopted as a type of transitional environment to enhance and prepare players’ spatial perception. This view of replicating virtual environment elements in the real world as a transitional environment is innovative. Although statistical significance of the result is not conclusive, the results offer evidence that warrants further research into this approach.
Thirdly, spatial perception seems to have a moderating influence on gameplay in VR games, affecting practice’s effect on enhancing players’ game performance. The moderating effect has different implications for real-world and virtual-world practice as the spatial perception varies, indicating that if the spatial perception of a player varies, the effect of practice on their game performance will vary as well. Virtual-world practice tends to be more effective at improving game performance if a player’s spatial perception is more accurate. If a player’s spatial perception were less accurate, real-world practice would be more helpful. Furthermore, if there are limitations to improving a player’s spatial perception, real-world practice may provide support. Practice within the virtual environment is not the only option. Limitations on improving player spatial perception may include a lack of visual distance cues in the virtual environment caused by design requirements, issues with the VR hardware design, and player cognitive ability to perceive virtual space.
Fourthly, spatial perception in VR games is definitely worth further research. Such research may not directly affect VR gameplay, but it may influence the effects of practice in tutorials. The effects of various elements (e.g., narratives, character designs) in a VR gaming experience can potentially be influenced by spatial perception. The attention to the role of spatial perception in the entertainment context is presently limited. The current findings offer justification for future studies to focus on the role of spatial perception in the effects of various elements of VR games.
Finally, real-world practice was effective at making new players more confident before their first gameplay session. Players understood that they were practicing only some of the tasks required in the game, yet the real-world practice remained effective at giving them confidence. This finding indicates the strength of real-world practice as a preparation for VR gaming, suggesting that practicing tasks in the real world can improve player confidence in performing tasks required in a VR environment. In the experiment, virtual-world practice was not demonstrated to be effective at improving player confidence. Thus, the real world is suggested to be a suitable place for new players to gain confidence for a VR game.
6.2. Practical Implications
The study proposes to use the tutorial as an opportunity to provide practice with the goal of improving players’ spatial perception of the virtual environment of a VR game. The results have indicated that VR game designers should consider viewing game tutorials as a means of improving players’ spatial perception before they enter the core gameplay of a VR game. The moderating role of spatial perception suggests that spatial perception may not directly affect the gameplay experience but it may influence the effects of various elements such as tutorials in a VR game.
The study also proposes an approach for VR game practice in the real world to improve spatial perception. This approach does not require a virtual replica of the real environment (as do other transitional environments explored in previous studies [
20,
21,
22,
24]) when a player starts a VR game, expanding its applicability. The approach of real-world replica of VR game elements may be limited in some contexts, as VR games can offer beneficial experiences and interactions not possible in the real world. However, some VR game elements are based on the real world, such as guns in the VR shooting game
Arizona Sunshine (2016) being based on physical guns. Our approach to real-world replication can only replicate parts of the physical forms of tools and mechanics in the challenges that are possible in the real world. This limits the applicability of the approach. However, we believe it remains applicable to many cases, such as shotgun gameplay in
Raw Data (2016) and archery shooting in
The Lab (2016).
Another limitation of real-world practice is that real-world replicas of virtual-world items must be tailor-made for each VR game, which may increase costs and prevent distribution across online sales channels. However, there are examples where game companies have sold games with physical boxsets via traditional channels: the Nintendo Labo (2018) series and Ring Fit Adventure (2019) for the Nintendo Switch game console. The success of these cases demonstrates the commercial feasibility to develop games with physical props.
A limitation of real-world practice is that visual effects in VR games, such as fire and holograms, cannot be replicated in real-world practice. We actually see this as a benefit because fewer effects can reduce the risk of spoiling details of the actual game. Real-world practice allows players to practice with tools and challenges without sacrificing any surprises planned in a VR gameplay by the game designers.
6.3. Limitations
The current study has its limitations. Only three aspects of the virtual world experience are covered herein: game performance, confidence, and spatial perception. Therefore, future studies should investigate other aspects of virtual experiences. Despite the limited coverage of the aspects of virtual experiences, the results of the current study reveal interesting patterns about the moderating role of spatial perception. This warrants future studies on the influence of spatial perception on various aspects of the entertainment experience of VR.
A relatively simple VR game was used in this study. Future studies should investigate the effects of real-world practices on other types of VR games or virtual environments. For instance, the results of the current study were obtained using only one VR game called Room on Fire. The challenges built into this game require players to perceive distances, which qualifies as a material for the study. However, many other different forms of VR game mechanics are available that require perception of the virtual space, such as shooting moving targets (e.g., zombies) and lobbing objects by using controllers (e.g., basketballs). Therefore, other forms of game mechanics should be analyzed in future studies.