The current study aimed to address the usefulness of our VR-based program for promoting subjective well-being. For acceptability, it is important that there are only manageable adverse effects when using the system. In this study, all participants completed the program without giving up. Given that the weighted mean SSQ score of the projection type of the head-mounted display used in the current study was 29.9 [37], our score of 24.4 suggests that the program causes an acceptable level of adverse effects of cybersickness.
The total task score calculated after completing the program showed a moderate correlation with most of the scale scores for psychological factors affecting subjective well-being, suggesting that the total task score may have good concurrent validity for assessing well-being, self-esteem, hope, and optimism. Unlike other measures, the MHC-SF social well-being score was not associated with the total task score, presumably because the contents of our program focused on the inner self concerning well-being. This result also reflects the fact that the elements of well-being are related to each other but are clearly distinct from each other [38].
The anti-difficulty score showed a linear relationship only with the MHC-SF emotional well-being score. Since participants selected the most difficult area of their current lives, such as family relationships, interpersonal relationships, academics and career, and leisure/habits/health, during the experience-based problem recognition task, the VAS score for experienced difficulty reflected the intensity of current stress. As the anti-difficulty score was the inverse of the intensity of stress experienced by participants, larger scores mean less stressful experience. Emotional well-being is the primary reflection of pleasant emotions and happiness [39]. Several studies have reported that perceived stress in various aspects of the environment had negative correlations with subjective well-being [40, 41]. Taken together, the result that the anti-difficulty score had a specific association with emotional well-being suggests that the current level of stress has a decisive effect on emotional well-being, including happiness.
The resolvability score had a linear relationship with both agency and pathways dimensions of the DHS. The contents of the experience-based problem recognition task focused on the will and action plan, and the resolvability score was a measure of the degree to which participants expected to be able to resolve the difficulties experienced. Accordingly, the higher the score, the more likely participants think that they will be able to overcome life’s challenges. The direct relationship between the score and hope is consistent with the previous findings that hope is clearly related to the expectation that positive outcomes will occur through one's own plans (pathways) and motivations (agency) [42]. Despite the similarity between hope and optimism, however, the resolvability score showed no linear relationship with the LOT-R score. In fact, optimism is primarily concerned with the expectation that positive outcomes will occur regardless of one's actions unlike hope [35, 43]. Some studies comparing the effects of hope and optimism reported that while both predicted life satisfaction, a positive effect on academic performance was only related to hope, not optimism [44, 45]. Our results indicate the importance of hope over optimism in terms of the willingness to overcome life's challenges.
The actual effort score predicted the MHC-SF social and psychological well-being scores. This score was about efforts to overcome difficulties, and thus higher scores indicate more of the effort. Such efforts are associated with stress, and much of the stress people experience is related to social factors [46]. The close relationship between the degree of actual effort and social well-being is understandable in that most topics presented in the experience-based problem recognition task belonged to the social realm. The model of social well-being has focused on the individuals’ evaluations of their public and social lives [38, 47]. Meanwhile, since psychological well-being mainly reflects the point in life at which a person realizes his/her potential and tries to resolve his/her problems [3], the close relationship between the degree of actual effort and psychological well-being seems to be inevitable.
The likelihood-of-realization score predicted the MHC-SF emotional and psychological well-being scores and LOT-R score. The future self-based success story expression task was to visualize a positive outlook on one’s future. Because the score was about the participant's future positive appearance, higher scores may reflect more optimistic attitude toward his/her future goals. The task contents were based on the concept of “best possible self,” a positive psychology intervention [14]. Disclosive writing about possible selves has been found to improve emotional adjustment through learning about oneself, restructuring one’s priorities, and gaining better insight into one’s motives [48–51]. In addition, emotional well-being and optimism can be increased through a program asking a person to visualize a life consistent with his/her ideal self [52]. Therefore, the likelihood-of-realization score seems to be linked to subjective well-being and optimism through the concept of “best possible self.”
The strength utilization score showed a linear relationship only with the DHS agency dimension score. The strength expression task aimed to help participants to explore and identify their character strengths. We expected the contents of this task would be associated with the process of strength identification that is important for strengthening subjective well-being. However, the resultant score showed association with agency dimension rather than pathways dimension of hope because the question did not ask how much participants identified their strengths, but asked how much they were taking advantage of the strengths. Higher scores indicate that participants evaluate their utilization of the strengths more positively. Therefore, our finding suggests that hope may be important to exploit strengths. Previous studies have reported that strength knowledge identifying and devising strengths has a positive correlation with hope [53, 54], and hope mediates between strength use and strength knowledge [55].
The interpretation of our results should be considered with caution. First, we limited participants to young men because the purpose was to only evaluate the usefulness of the program. A more intensive applicability study should be conducted with a more diverse sample including a broad range of age and female. Second, this experiment was only a one-time experience of our program. To be used for training purposes, a systematic repeating schedule is required. Third, the program relies only on subjective evaluation. Objective evaluation systems, including the use of biosignals, need to be added for further development.