Bringing nature into hospital architecture: Machine learning-based EEG analysis of the biophilia effect in virtual reality

Abstract

In recent years, there has been a growing interest in investigating the influence of biophilic design on occupants' psychological comfort and well-being in the built environment. Biophilic principles aim to leverage the therapeutic effects of nature to alleviate distress, depression, anxiety, and pain. The impact of biophilic design can vary depending on the outcome measures and the design context, but studies examining diverse forms of biophilic design in hospital rooms have been limited. The study investigated how the incorporation of biophilic design elements in a virtual reality (VR) hospital patient room affects emotional and brain responses. The purpose of this experiment was to measure interactive emotions in an experimental setting, using a combination of electroencephalogram (EEG) and VR methods. A machine learning approach and statistical analysis were applied to differentiate emotional changes related to biophilic design. Seventy-five participants were divided into three groups to investigate the distinct effects of three types of biophilic design. EEG recordings were taken during experimental conditions to determine how biophilic design affects brain and emotional states. The Positive and Negative Affect Scale (PANAS) and State-Trait Anxiety Inventory - state (STAI-s) were used to measure changes in emotion and anxiety state. The results of the machine learning application on EEG data showed that classification accuracy above 90% included the frontal region in all classification conditions, indicating that biophilic design causes changes in brain function in this region. For the classification of the control room and digital wall room, and the control room and both plant and digital wall room, alpha power for frontal regions was included with above 90% classification accuracy. The results of the statistical analysis of the EEG data found that low-frequency band, which is associated with a relaxed state, was increased by biophilic design, while high-frequency band, which is associated with high arousal state, was reduced. These findings suggested that biophilic design in a hospital room can reduce tension. The results from PANAS and STAI-s showed that biophilic design can induce positive emotional changes. The results of PANAS suggested that adding plant walls can reduce negative emotions due to their calming effect on the human nervous system. Using both plant walls and digital elements in healthcare environments can have a complementary effect on emotional well-being by reducing negative emotions while enhancing positive emotions. The study can potentially contribute to building a deeper and unified knowledge base for developing evidence-based designs to improve mental health and well-being. Moreover, the study provides insights into the potential benefits of different forms of biophilic design and their impact on human well-being.