Exploring Green Wall Sizes as a Visual Property Affecting Restoration Effect and Stress Recovery in a Virtual Office Room

Natural environments potentially have positive impacts on stress recovery by restoring depleted sources. Integrating natural objects into the built environments can create a restorative built environment. On the other hand, some factors, such as visual stimuli and their properties, can impede the design intentions of such restorative environments. Differences between visual properties of natural environments may change restorative effects by affecting human attention. This study aims to investigate the impact of the size of a green wall on restoration, stress, and attention in a virtual office environment. Twenty participants were recruited to experience two comparable environments with different green wall settings, a large and a small green wall. During the experiment, participants' physiological responses, heart rate (HR), electrodermal activity (EDA), stress index (SI), and eye movements were measured to assess their stress and attention. The restorative state scale survey was administered after each environmental exposure. The results showed that there were no significant differences between responses recorded in two different settings. A small sample size may explain these results since higher restoration and stress reduction were expected in a virtual environment with a large green wall. In addition, comparing physiological responses during the stressor task and restoration in each session showed the restoration effect of exposing to both virtual environments with a green wall. The results are further explained using the green wall size selection, importance of including a non-green wall condition, and the impact of sample size.