# A Comparative Study of Real and Virtual Environment via Psychological and Physiological Responses
## 4 Discussion
Despite the power of these visualization tools, there is a scarcity of studies that compare human responses in real and IVEs [30; 32; 33], especially in relation to psychophysiological responses; these studies are necessary. This study proposes an experimental protocol to compare a real and virtual environment via collecting psychological and physiological responses in combination with the sense of presence, based on the visualization of an IVE scenario in head-mounted displays (HMD). Three issues stand out from this experimental protocol. Firstly, it is essential to measure the physiological response, as cognitive-emotional states are characterised by both psychological and physiological responses [59]. It should be noted that although several works have studied the use of IVE systems in the assessment of subjects' cognitive performance [17; 22; 60], there are fewer studies that have analysed IVE and physiological responses, such as EEG, HRV, and EDA [61; 62; 63]. Secondly, it is important that IVEs can generate a high level of sense of presence in subjects [11; 37]. Although this system is questioned in terms of its reliability and inability to provide real-time information [64], it plays an important role in studies on environmental psychology and architecture. It is a fast and low-cost system that allows for the validation of multiple design configurations, which is hardly achievable with real vs. virtual comparison. Thus, there would be a dual validation system: initially, the starting scenario is validated using real vs. virtual comparison, and subsequently, each design configuration, hardly transferable to physical space, is validated using the presence test. Thirdly, the utilised support, the HMDs, is crucial. These provide fully immersive systems that isolate the user from stimuli in the external world. Additionally, some studies demonstrate that emotional content enhances the sense of presence in an IVE [65], and that, when exposed to the same content, the self-reported intensity of emotion is significantly higher in immersive environments than in non-immersive ones [66]. Therefore, IVEs, which showcase 360\({}^{\circ}\) panoramas or 3D scenarios using an HMD [67], are powerful tools for psychological research. Finally, in relation to the limitations of this study, it is worth noting that there is currently a wide range of HMDs available on the market. Some of these HMDs, with more limited capabilities, such as resolution, field of view, and refresh rate, may provide lower levels of accuracy. This suggests that their use should be undertaken with caution. However, the ongoing advances in HMD technology suggest that this problem will be overcome in the near future. This study also presents as a limitation the choice of only one point of view within the classroom (the center of the second row of tables). This could have included a position-related effect. An experimental approach with different positions could have reduced this effect, but it would have required a larger sample of participants. Another limitation of this study is that the subjects of the experiment were all university students. Therefore, the results are limited to this specific demographic group. Given that the demographic characteristics of the subjects could affect their previous experience and adaptability to HMDs and their resulting responses, additional experiments would be needed to generalise the findings of this study to other demographic groups.