Biofeedback-Informed Assessment of Biophilic Interior Variables: A 23 IVR Factorial Study in Design Studio Interiors

This study investigates the influence of three biophilic interior design variables: natural light, interior vegetation (vertical green wall), and biomorphic form (biomorphic wall panel) on affective and physiological responses in a design studio interior utilizing immersive virtual reality (IVR) and wearable biofeedback technology. This study was a within-participant 23 factorial design that included one baseline and eight IVR studio conditions. Participants experienced all conditions while reporting affects using the Self-Assessment Manikin (SAM) valence and arousal scales, electrodermal activity (EDA), and skin temperature (ST). Cybersickness was measured with the Simulator Sickness Questionnaire (SSQ) and presence was assessed using the Igroup Presence Questionnaire and Slater-Usoh-Steed presence measures (IPQ, SUS), while baseline anxiety (STAI) was controlled. The results demonstrated a significant primary influence of natural light on SAM valence ratings: conditions with natural light were evaluated as more pleasant than the non-variable and baseline condition, whereas interior vegetation and biomorphic form had smaller, context-dependent effects that were most evident when layered with natural light. Differences in SAM arousal ratings were modest and non-systematic. EDA did not differentiate, and ST showed only small shifts, indicating that during calm exploratory monitoring, subjective affect was more responsive. The circumplex findings guided to an activity-specific zoned interior rather than a single uniform design studio.