## 2 Literature Review
### Auditory Evaluation Factors in the Presence Evaluation Questionnaire for a Metaverse Environment
In the MEC-SPQ, there are questions that consider the user's state, behavior, and sense of presence, and, in particular, the questionnaire on the sense of presence consists of questions about the sense of location of the user and the objects surrounding them, and questions about whether the impression (feeling) received in the virtual environment allows the user to control their behavior [37]. As shown above, the evaluation factors of auditory presence in the questionnaire for evaluating presence in metaverse environments were examined and are shown in Table 2.  
As shown in Table 2, the characteristics of the presence questionnaires include sensory stimulation, participation, immersion, interaction, attractiveness, distraction, and consistency, but there is very little information about auditory presence, or it plays a supporting \begin{table}
\begin{tabular}{c c c c} \hline \hline
**Type of Questionnaire** & **Characteristics of Presence** & **Auditory Presence Evaluation** & **Classification of Presence** \\ \hline \multirow{4}{*}{PQ [22]} & \multirow{4}{*}{\
\begin{tabular}{c} Sensory stimulation, engagement, immersion, and interaction \\ \end{tabular} } & Whether you focus on content due to hearing (QN 6) & \\ \cline{3-4}  & & Identification of sounds (QN 15) & Presence \\ \cline{3-4}  & & Location of the sound recognized & \\ \cline{3-4}  & & (QN 16) & \\ \hline SUS-PQ [32] & Comfort, naturalness, and immersion & No auditory presence factor & \\ \hline \multirow{4}{*}{RJPQ [34]} & \multirow{4}{*}{Natural interactions} & Auditory clarity (QN 4) & Realism \\ \cline{3-4}  & & Similarity to real-world sounds & Reality judgment \\ \cline{3-4}  & & (QN 73) & \\ \cline{3-4}  & & Focus on content due to hearing & \\ \cline{3-4}  & & (QN 76) & Presence \\ \hline IPQ [25] &
\begin{tabular}{c} Subjective experience, immersion, and interaction \\ \end{tabular} & No auditory presence factor & \\ \hline ITC-SOPI [35] & Appeal, naturalness, and credibility & No auditory presence factor & \\ \hline E2 IQ [36] & Attractiveness, distraction, realism, consistency and immersion & Distractions from noise outside the & Distraction \\ \hline MEC-SPQ [37] & User state, behavior, and presence & No auditory presence factor & \\ \hline \hline \end{tabular}
\end{table} 
Table 2: Characteristics of presence evaluation questions and auditory presence evaluation factors in metaverse environments by evaluation questionnaire. role to visual aspects. This suggests that sensory realization technology is becoming important for improving the presence of metaverse environments, and given the literature review indicating that auditory factors contribute significantly to presence, especially with the development of audio technology, auditory factors should be expanded to evaluate sensory stimulation, participation, immersion, interaction, attractiveness, and consistency, which can affect presence [13; 14; 15]. In addition, it is difficult to evaluate the auditory features of the interface (keyboard, mouse, display, etc.) of a metaverse platform that is familiar to real users, as the existing perceived presence evaluation questionnaires consider VR devices such as head-mounted display interfaces. In other words, VR devices are the iconic interface of the metaverse environment, but the most popular metaverse platforms used by real users are 'ranking 1, Roblox', 'ranking 2, Minecraft', and 'ranking 3, Fortonite', which utilize existing interfaces [38]. Considering the utilitarian aspect of the auditory presence evaluation factors, it is believed that a presence study based on the interfaces of the most popular metaverse platforms used by current users should be conducted first, rather than a presence study on VR interfaces. Therefore, the study was conducted to identify auditory factors that can enhance the sense of presence in a metaverse environment, to componentize auditory evaluation factors for auditory presence and AUX, and to determine the relationship between auditory evaluation factors and the enhancement of presence.