The outbreak of the coronavirus disease (COVID-19) has triggered significant changes in the behavior of people in terms of work environment, as they have to stay indoors for longer periods compared to the pre-pandemic era. Moreover, the significance of indoor spaces has been emphasized even before the pandemic as people typically spend 90% of their lifetime indoors for reasons, such as service, knowledge work, or production (Kim et al. 2021; Cho et al. 2021). As the lockdown and social distancing make it difficult for people to go outside for work, significant number of companies encourage employees to work from home, while maintaining productivity and professionalism (Nediari et al. 2021). However, in some cases, it is challenging to maintain proper work performance at home. Traditionally, telecommuting was believed to guarantee high productivity under normal situations. However, the COVID-19 period exposed telecommuters to stress due to special situations, such as child-care support, and family work violations in individual work (Chang, Chien and Shen, 2021). Therefore, it is crucial for individuals to have a designated space for work during work hours. Currently, enhancing the productivity of work-at-home individuals through indoor designs that prioritizes human comfort and needs has attracted research attention (Lee et al. 2022; Zitars et al. 2021). Moreover, as smart work becomes increasingly prevalent, the construction of spaces that can handle both labor and rest is essential. In addition, consumers are becoming increasingly interested in the philosophy and cultural appreciation of indoor spaces, so telecommuting environments should be designed to be more sensory-centered and accommodating to human needs.
To understand the effects of indoor environment on task performance, Kim et al. (2020) investigated the relationship between work productivity and thermal performance. They found that there is a positive relationship between alertness and working memory under warm conditions (25.7°C), whereas there is a negative relationship between executive ability and mental workload under cool conditions (17°C). In addition, Duyan and Ünver (2016) investigated the effects of the color of the wall on the attention of students, and found that purple and red walls contributed to higher work performance. Regarding the size of space, Marchand et al. (2014) found that there is a negative relationship between listening and reading tasks in spaces with low ceilings. These aforementioned studies have identified the effect of each detailed indoor space composition on task performance, but studies on work productivity in a comprehensively designed space with various factors are few. Therefore, it is essential to design an optimal indoor space that considers these factors to achieve the highest work efficiency.
Banaei et al. (2020) reported that certain aspects of the interior design, such as color, wall material, and ceiling height, can affect the physical and mental health of humans. Researchers have investigated how people adapt to indoor environments using physiological indicators, such as electroencephalogram (EEG) or electrocardiogram (ECG). For example, white or green walls make a space appear wider, and higher ceiling heights can increase the ’resilience of users. These effects have been validated by measuring brain waves and observing a relatively large number of alpha waves, which indicated a relaxed feeling (Lee, Shin and Lee 2020; Kim and Ha, 2022). Araujo et al. (2020) conducted an experiment to understand the relationship between light and physical health, and found that heart rate variability (HRV) relaxation occurred under red light, whereas active heart rate emerged under white light. Although a number of studies have been conducted to propose the optimal interior design composition, only few indoor spaces with a favorable psycho-physiological effect on humans have been developed. To better understand the relationship between space and task performance, research should be conducted in environments where the individual feels a realistic sense of space. In this context, virtual reality (VR) and mixed reality (MR) can be used to create immersive environments that emulate actual space under controlled experimental environment. Several studies have demonstrated that when implemented, there is no notable distinction in the VR- and MR-created environment from reality. Puyana-Romero et al. (2017) extended the validation of VR technology to the evaluation of the urban environment using a head-mounted display (HMD) and a laptop or desktop computer, and found that there was no significant difference in the real and VR environments in the subjective evaluation results. Moreover, Hong et al. (2021) reported that the utilization of mixed reality technology in outdoor urban settings had no significant effect on the evaluation of the soundscape compared to the physical environment. These results suggest that sufficiently valid results can be obtained when VR and MR technologies are used for subjective evaluation. Overall, these results suggest the applicability of MR technology to progressive, practical research for identifying interactions between indoor space design and task performance.
Physiological indicators reflect the status and responses of the human body system, such as the autonomic nervous system, which consists of sympathetic and parasympathetic divisions. Visual stimuli induce responses and affect the physical stimuli and behaviors of individuals through stress (Kim, 2013). The Yerkes-Dodson law (1908) indicates that the enhancement of the task performance under stress is proportional to physiological arousal up until a certain point, beyond which an increase in stress results in a decrease in performance. Therefore, variation in interior design, such as color and layout, can affect heart rate, stress levels, workload, and task performance (Cha et al., 2020). To provide the optimal design for telecommuters, it is essential to understand their physiological indicators and work performance based on the indoor space design. Thus, further efforts are required to comprehend the state of end-users and the work efficiency in their preferred space.
The aim of this study was to examine the impact of various indoor space designs on physiological responses and task performance, and to explore the relationship between work efficiency and physiological indicators. To achieve this, this study utilized psycho-physiological indicators and cognitive tests to analyze the physiological effects and task performance of participants under various spatial compositions. First, the preferred and non-preferred spatial compositions of individuals were determined through a preliminary survey. Subsequently, an actual experiment was conducted on 30 participants using an MR technology, in which the virtual environment was adjusted into the actual room dimensions, and task performance scores were examined using conducting cognitive tests. During the tests, the ’EEG and HRV of the subjects were measured to obtain the psycho-physiological indicators in each room. Lastly, the differences and impacts of the indoor space on the physiological state were explored by applying various statistical method, such as normality analysis, repeated measures one-way analysis of variance (RM ANOVA), Friedman's test, and linear regression analysis. Moreover, correlations between task performance and psycho-physiological responses were analyzed using Spearman rho's analysis.