Evaluating Biophilic Design strategies in Immersive Virtual Indoor Environments: A systematic review on the implications for buildings occupants

Nowadays, investigating the impact of Biophilic Design (BD) on human health, well-being, and cognitive performance is at the forefront of concern in academia, particularly in the context of creating sustainable and comfortable buildings by fostering a deeper connection to nature. In parallel, the advancement and accessibility of Virtual Reality (VR) have facilitated the rise of immersive studies on BD, offering advantages in terms of flexibility, cost-effectiveness, and control over independent variables. However, despite the body of research is growing, it remains fragmented, with heterogenous design of experiments and methods across studies, particularly concerning the outcomes of BD impact on human dimension. This is due to the novelty of these topics which did not allow the systematical synthetisation of the potential benefits of VR-BD applications. As a result, the present paper addresses the need to consolidate an emerging and under-investigated field, offering a systematic and comprehensive overview of the current literature to advance research application. In particular, the review focuses on the applications, potentials, and constraints of the use of Immersive Virtual Reality to investigate the impact of indoor Biophilic Design on occupants’ dimension, in terms of environment perception, physiological and psychological indicators and cognitive functions. Although the first literature dates back to 2015 and most of it is concentrated in the last 5 years, enough information has been gathered to provide a systematic review of the methods used and the main results collected, which can serve as a guideline for future research on this emerging topic. The systematic review, based on the PRISMA method, provides a clear picture of the methodological design of the studies (e.g., VR technology and software employed, participants sample size, exposure time, ecological validity methods), on the considered independent variables (i.e., the BD patterns); and on collected dependent variables, related to perception domains (i.e., acoustic, visual and thermal perception, perceived restoration), physiological parameters, psychological and cognitive aspects. The review then reports and analyses the main outcomes from the research in terms of the impact of indoor biophilic strategies on dependent variables, outlining a rather fragmented picture and only partially supporting the theories of BD. Finally, the review presents the main shortcomings and limitations in the design and documentation of the reviewed studies, as well as potential future research developments, especially based on the exploitation of advantages of VR technologies in terms of a great number of randomized and multi-domain scenarios to be tested.