# A Comparative Study of Real and Virtual Environment via Psychological and Physiological Responses
## 1 Introduction  
Immersive virtual environments (IVEs) are virtual reality environmental simulations reproduced using systems highly isolated from the physical environment; this isolation makes their users perceive they are not synthetic [1]. Their virtuality and accessibility [2] allow them to generate simulated spaces that can be dynamically altered based on their users' responses [3]. This can be achieved under controlled conditions and in very environmentally [4] and economically sustainable ways [5]. This makes them powerful tools to assess users' responses to a variety of stimuli not easily controllable in physical environments [6]. Very different domains have taken advantage of these capabilities. Above all, those in which the user's interaction with his/her environment is important, such as medicine [7], product design [8], environmental design [9], and education [10]. Architectural design is no exception; IVEs allow researchers to investigate the responses of users to different design alternatives and, thus, facilitate decision making. Many studies have used these tools to incorporate users' responses into architectural research [11; 12; 13]. Within the architectural field, the potential of applying the IVE to the design of spaces with different uses stands out [14; 15; 16]. In fieldwork, researchers often face challenges in modifying spaces to represent study variables or selecting diverse spaces to capture variable conditions. Both approaches have drawbacks; the first is costly and time-consuming, while the second may encounter methodological issues related to applying ceteris paribus logic. This logic involves identical designs with differing variables, necessitating a large sample of spaces. However, these limitations are overcome using IVEs. Furthermore, because oftheir level of experimental control, IVEs have been used to enhance attention in the absence of unexpected distractors [17], and it has been suggested that IVEs could improve the validity of measurements and treatments [18]. In fact, many studies have validated teaching IVEs for the assessment and rehabilitation of attention deficit hyperactivity disorder (ADHD) [6; 19; 20; 21; 22]. The advantages of IVE for research into architectural spaces are more evident for certain variables such as their geometry. However, more studies have analysed, for example, environmental variables such as temperature, air quality, acoustics, and lighting [23]. The complexity of modifying the geometry of physical spaces has had the consequence that it has been examined to a lesser extent [24], although several architectural studies have emphasised the importance of volume and, specifically, ceiling design [25]. Furthermore, IVEs are compatible with the simultaneous application of various physiological measurement devices to record users' responses to simulated spaces. Thus, several physiological measures can contribute to the study of performance in teaching spaces. For example, electroencephalograms (EEG) [26; 27], heart rate variability (HRV) [28], and electrodermal activity (EDA) [29] have proven effective in evaluating attention. Some authors have even suggested, given their greater experimental control, that the results of physiologically evaluating users with IVEs are more rigorous than those achieved in physical settings [18]. However, the application of immersive virtual environment (IVE) systems requires a critical evaluation of their validity. The question arises as to how closely simulations resemble the physical environments they seek to recreate. Numerous studies have addressed this issue via comparing the responses of subjects to simulated settings with their responses to physical settings. In general, equivalence has been discovered in various types of settings for different psychological responses. For instance, self-report measures in a conference center [30] exhibited few statistically significant discrepancies between the ratings of the real and virtual buildings based on quantitative data.