The Cognitive Impacts of Implementing Biophilia in Architecture
Laura Liu, David Wu, Cameron Bishop
Abstract
The profound connection humans have with the natural world transcends mere aesthetic appreciation, profoundly influencing our overall well-being and cognitive functions. In recent years, rapid urbanization coupled with the shift to indoor-oriented workspaces, exacerbated by the aftermath of the COVID-19 pandemic leading to a surge in hybrid and remote work arrangements, has underscored the need to prioritize environments that integrate biophilic design principles. Research indicates that such integration in workplaces, schools, correctional facilities, fitness centers, and other settings not only enhances satisfaction and productivity but also fosters superior mental health outcomes compared to conventional urban-centric environments. Consequently, there is growing recognition of the importance of infusing natural elements into these spaces.
This meta-analysis delves into the diverse advantages offered by natural environments, juxtaposing them against the often sterile and stressful settings prevalent in urban locales. It emphasizes the indispensable role of biophilia in shaping modern spaces. By probing into inquiries such as the ways biophilic architectural features can elevate quality of life and mitigate stress, and examining the impacts of elements such as plants, natural light, water, and exposure to nature on mental health, we aim to substantiate the assertion that biophilia exerts a positive influence on psychophysiological well-being.
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As biomedical scientist Stephen Ilardi noted, "We were never designed for the sedentary, indoor, socially isolated, fast-food-laden, sleep-deprived, frenzied pace of modern life." Our findings bolster the argument that embracing biophilia can help ameliorate the detrimental effects of contemporary lifestyles, particularly concerning mental health.
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Echoing the sentiments of Edward O. Wilson, who remarked, "We have Paleolithic emotions, medieval institutions, and godlike technology," our study underscores the urgency of innovation that addresses these primal needs. Failure to do so risks consigning humanity to a state of perpetual stagnation, drifting away from our evolutionary roots while grappling with technologies far removed from our innate capacities.
The Biophilia Hypothesis
Biophilia, a concept coined by the biologist Edward O. Wilson in the 1980s, proposes that humans possess an innate genetic predisposition to seek connections with nature and other forms of life, and consequently have psychophysiological benefits as a result of these relations (Wilson). Nature is characterized as the laws, elements, and phenomena of the physical world, including life; more specifically, the elements of nature humans can adapt into their everyday lives that are not already anthropomorphic. One of the biggest ambassadors of biophilia, Stephen R. Kellert, in the 14 Patterns of Biophilic Design states a middle ground for defining nature is, “[The] living organisms and non-living components of an ecosystem” (Kellert 2014). Wilson suggests in his book Biophilia that humans have evolved to have an emotional connection with the natural world due to their long history of coexistence with it. He explores how this biophilic connection has evolved and its significance in human evolution, arguing that our ancestral environments heavily influenced the development of this bond with nature. However, he stresses how modern development has integrated exponential industrialization without regard for biological elements in design. In his claim that exposure to nature can positively impact mental health, reduce stress, and improve overall well-being, he addresses the challenges of maintaining our biophilic connection in increasingly urbanized settings and suggests incorporating elements of nature into urban design and architecture to enhance human well-being. The Biophilia Hypothesis presents a compelling argument for the importance of our innate connection with forms of life. Ultimately, the psychophysiological effects of biophilia observed in architecture further exhibit evidence for our predisposed affinity for nature.
Psychological effects
Numerous studies have endeavored to elucidate the impact of the Biophilia hypothesis on the human psyche, employing diverse methodologies ranging from self-reporting to behavioral assessments, albeit with varying degrees of success. While the tangible physiological changes in subjects' bodies may not always be apparent, a discernible shift in surveyed responses post-exposure to biophilic or natural stimuli is frequently observed.
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In 2020, Shih-Han Hung and Chun-Yen Chang, comprising a doctoral student and a professor, conducted a comprehensive meta-analysis of forty-five research papers on biophilia. Motivated by the lack of literature on the health benefits of biophilic design, their work aimed to operationalize the psychological and physiological effects associated with it. Hung delineates psychological well-being to encompass attributes such as positive emotions, tranquility, relaxation, and low levels of anger, among others.
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Biophilia researcher Matthew White and his team investigated the effects of outdoor exposure on well-being, utilizing a self-report scale. Engaging a sample of n=19000 participants, they found that increased time spent in nature correlated positively with reports of enhanced well-being and good health. However, their findings also revealed diminishing returns after approximately 120-179 minutes per week of additional exposure to nature.
In Chang and Chen’s study on “Window views and Indoor plants in the Workplace,” they observed the psychological effects of these “biophilic” features with a State-Anxiety Inventory. In this test, there were 20 questions based on four rating scales, and the individual scores can range from 20 (high anxiety) to 80 (low anxiety) where the study participants rated questions such as “I feel calm” or “I feel nervous”. The 38 students studied were shown 6 combinations of of slides from several different conditions of varying degrees of biophilic elements as indicated in the following table:
The anxiety rating was found as follows:
With a 15.53 higher mean for reported anxiety from the O with no added biophilic elements to the NP condition with multiple biophilic elements (Chang & Chen 2005). While not demonstrating the full range of psychological effects of biophilia, this element of the study demonstrates the connection between lower anxiety and the perception of nature. In a between-subjects experiment by Jie Yin et al, the researchers looked to connect more deeply the connection between stress reduction and incorporating natural environments. They measured both the impact on the psychological state and physiological indicators, finding that participants in biophilic indoor environments had “consistently better recovery responses after stressor compared to those in the non-biophilic environment, in terms of reduction of stress and anxiety”. This was measured over 100 healthy adults in 2018 using a predesigned stressor in VR, followed by the exploration of one of four settings, one without biophilic elements, and three similar environments enhanced with different biophilic design elements. The environments are shown as follows and were coded as the A, B, C, and D Labels.
Water
Water, despite its nonliving nature, plays a pivotal role in biophilic design, offering additional sensory dimensions to architectural spaces. Its incorporation not only serves as a distinctive design element but also introduces non-visual biophilic qualities. In a study conducted by Nevzati et al., the impact of integrating water features into workspaces on the mental states of employees and students was investigated. The study focused on individuals who frequented the area both before and after the installation of water features, revealing findings that supported the hypothesis that water may enhance mental well-being and alleviate mental fatigue in environments characterized by constant stressors. Post-implementation surveys, encompassing various water features such as aquariums, waterfalls, ponds, and paintings, consistently reported improved moods and reduced stress levels among participants. Notably, the gentle sounds of flowing water were highlighted as contributing significantly to the therapeutic ambiance, suggesting that the live integration of water into architectural design is particularly effective in stress reduction.
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While visual representations of water are beneficial, the inclusion of auditory water features adds dimension. Research conducted by Nevzati and other proponents of biophilic design, such as Matthew White, underscores the significance of mitigating noise pollution, a prominent stressor in environments. Live, flowing water emerges as a viable solution in this regard.
The researchers concluded that participants in biophilic environments exhibited faster recovery rates, as indicated by an increase in RMSSD (root mean square of successive differences between normal heartbeats). Specifically, the mean increase rate of RMSSD was observed to be 2.1% faster in environments classified as "Indoor Green," suggesting significant recovery from stress conditions. However, it is important to note critical limitations in the study, particularly regarding the "Non-Biophilic" condition, which lacked natural light and biophilic elements typically present in habitable spaces.
Physiological effects
Hung and Chang defined physiological health. They say it is measured by “low physical tension, such as lower heart rate, blood pressure, and pain” but our analysis expects to go beyond just these qualifications (Hung & Chang). Because of the multifarious nature of the perceived impact of biophilia on several different systems in the body, such as the parasympathetic nervous system, blood pressure, alpha and beta brainwave activity, and any number of measurable effects, researchers attempt to isolate and measure each facet with a large number of different operational definitions. One of the most important examples of measuring the physiological effects of biophilia was in the 1984 writing by Roger S Ulrich. In his study on recovery rates post-surgery, it was found that patients with “natural views” were both requesting less analgesic doses and recovering a statistically significant number of days sooner.
Ulrich stated that “there were statistically significant variations between the tree-view and wall-view patients in the mean number of analgesic dosages T^2 = 13.52, F = 4.30 and P < 0.01.” and used this tendency of individuals with as we would characterize it, more biophilic views, to physiologically be in a state requesting less pain relief. This study is very highly cited, and the methodology where the physiological state of individuals was gauged in some manner by the dosage of medication in conjunction with the psychological measures measured from nurse comments has been emulated in a large number of forthcoming studies, where an attempt was made to link physiological measures and psychological evaluations.
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A noteworthy study that comprehensively assessed both psychophysiological indicators and psychological responses is presented in Kim and Mattson's research titled "Stress Recovery Effects of Viewing Red-Flowering Geraniums." This study employed a randomized assignment to three treatment conditions: viewing a red geranium, a nonflowering geranium, and no plants. Physiological measures encompassed EEG-based alpha and beta brainwaves, electrodermal activities (EDA), and finger skin temperature.
The study rationalized the use of alpha and beta waves by explicating that beta activity directly correlates with arousal levels, whereas alpha activity is inversely related. EDA was operationalized to gauge sweat gland activity in conjunction with the sympathetic nervous system's activation, preparatory for responding to stressors. Similarly, distal skin temperature was justified as an indicator of stress response, with the sympathetic nervous system causing a decrease in skin temperature during stress, followed by a rebound post-recovery.
In addition to these physiological measures, the study incorporated a self-rated assessment of students' emotions using an "Inventory of Personal Reactions." This multifaceted approach yielded several significant findings. For instance, the study observed a continuous decrease in EDA with red-flowering geraniums, reaching 65% recovery from induced stress levels, whereas EDA with non-flowering geraniums and no plants showed higher values than the induced stress level (11% and 16% increase, respectively). This suggests that the observation of flowering geraniums potentially mitigates stress, as indicated by electrodermal activity. Furthermore, the recovery process measured via EEG beta wave activity was notably faster, especially in association with red flowering geraniums, when compared to exposure to no plant stimulus, as depicted in the accompanying graph (Kim and Mattson 2002).
Concerning physiological measures to attempt to make a biophilic design with desired physical responses, they encountered serious issues in statistical responses in a certain number of responses, specifically the male subsect of the treatments. In this study, they hypothesized that “males showed rapid decreases with 75% recovery rate in three minutes”, regardless of biophilic stimulus. Although the female participants resolved a statistically significant response, there is complexity in measuring a stress response in a study even when carefully controlled.
Workplace Daylight Effects on Sleep Patterns
The "master clock" that regulates circadian rhythms consists of a cluster of nerve cells known as the suprachiasmatic nucleus (SCN) located in the hypothalamus. Destruction of the SCN leads to the disruption of the regular sleep-wake cycle, underscoring the crucial role of light exposure in maintaining circadian rhythm synchronization and consequently, physical health. The "Impact of Workplace Daylight Exposure on Sleep, Physical Activity, and Quality of Life" study conducted by researchers from the Interdepartmental Neuroscience program at Northwestern University in Chicago, led by Christopher Bergland, sheds light on the physiological impacts of natural light exposure in the workplace. Published in The Journal of Experimental Psychology, the study examined 49 day-shift office workers, with 27 in windowless workplaces and 22 in workplaces with windows, to investigate the relationship between workplace daylight exposure and various health-related factors. The research revealed significant correlations between exposure to natural light and improvements in sleep patterns, physical activity levels, and overall quality of life among employees. Workers with access to natural light experienced a substantial increase in white light exposure during work hours, resulting in an average of 46 additional minutes of sleep per night compared to those without windows. Conversely, individuals in windowless offices exhibited lower scores and poorer outcomes in measures of overall sleep quality, sleep efficiency, sleep disturbances, and daytime dysfunction. The study highlights the crucial role of natural light in regulating circadian rhythms and enhancing physiological well-being, emphasizing its importance in promoting healthy sleep patterns and physical activity levels in office environments. Additionally, health-related quality of life was assessed using the Short Form-36 (SF-36), and sleep quality was evaluated with the Pittsburgh Sleep Quality Index (PSQI), with workers without windows reporting poorer scores than workers with windows on all three PSQI subscores. Light exposure, activity, and sleep were measured by actigraphy in a representative subset of 21 participants, further validating the findings. The study underscores the significance of incorporating biophilic elements such as natural light into workplace design to optimize employee health and productivity.
​​Pittsburgh Sleep Quality Index (PSQI) measures workers in workplaces with windows (N = 22) and without windows (N = 27).
Physiological Effects of Light Exposure in Buildings
Light exposure in buildings has profound physiological effects on human health, encompassing visual and nonvisual impacts. One significant aspect is its role as the primary environmental cue for regulating circadian rhythms, synchronizing physiological and behavioral processes to the 24-hour light-dark cycle. However, the introduction of electrical lighting has disrupted this natural rhythm, leading to circadian misalignment, particularly notable in shift workers, and associated with increased risks of accidents, metabolic disorders, cardiovascular disease, and certain cancers. Conversely, strategic light exposure in terms of timing, duration, spectrum, and intensity has been studied to enhance alertness and productivity, and even treat conditions like seasonal affective disorder and sleep disorders. Experimental interventions with light have shown promising results in slowing the progression of neurodegenerative conditions and improving the quality of life among the elderly.
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Beyond circadian regulation, light exposure also has visually induced health impacts, including visual strain, eye irritation, and blurred vision, particularly under conditions of uncomfortable glare, high illuminance, and high-contrast lighting environments. Certain individuals, such as migraineurs, are particularly sensitive to light intensity and flickering, which can trigger migraine episodes even during non-episodic periods. Flickering at frequencies lower than 100 Hz has been associated with impacts on visual search performance and reading accuracy (Jaén EM, Colombo EM, Kirschbaum CF. 2011). Environmental psychology research has highlighted the restorative effects of aesthetically pleasing visual environments with biophilic elements, such as views of nature, which promote faster recovery from stress and mental fatigue and improve cognitive performance. Contemporary architecture aims to balance the trade-offs between daylight penetration, glare, and excessive solar thermal heat gains, utilizing novel modeling tools to predict lighting properties. The advancement of solid-state LEDs has enabled cost-effective solutions with tunable spectrum features, facilitating the manipulation of light to promote desired circadian phase shifting. Despite these advancements, the complex interplay between different lighting parameters and their impact on health outcomes presents challenges in issuing simple recommendations for optimizing indoor lighting environments.
Biophilic Design Effects on Physiological Responses in Office Environments
Biophilic design, which integrates elements of nature into built environments, has garnered attention for its potential to enhance human well-being and productivity. This section discusses an empirical study investigating the effects of biophilic design elements, particularly indoor plants and views of nature, on individuals' physiological responses in office settings (which was previously mentioned with a different focus on the psychological aspects). The study utilized a within-subject design, exposing participants to six different workplace conditions varying in the presence or absence of window views and indoor plants. Physiological measures, including electromyography (EMG), electroencephalography (EEG), and blood volume pulse (BVP), were recorded.
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Electromyography (EMG) was used to assess muscle tension levels in participants. On the other hand, electroencephalography (EEG) activity was used to evaluate participants' brainwave patterns, specifically focusing on alpha (resting) and beta (alert) activity. EEG was used to record bioelectrical responses, alpha activity occurs when a person is resting quietly. Beta activity occurs when a person is alert and aroused. Generally, higher alpha EEG activity is more associated with relaxed conditions than with states of stress. Restorative environments and experiences in natural areas provide for recovery from stress and, thus, should result in higher alpha EEG activity. Lastly, BVP signals were used to calculate heart rate and inter-beat interval, indicating cardiovascular responsiveness to stress.
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Results demonstrated significant differences in psychophysiological responses across the various workplace conditions. Environments incorporating biophilic elements, such as a window view of nature plus indoor plants, elicited the highest brainwave activity (EEG-b) and lowest levels of anxiety among participants. Comparing window views in general, window views of nature had the best effect on EEG-a, EEG-b, and BVP. Only EMG showed a lower effect compared to a window with a view of a city, and a window with a view of a city had a worse effect on EEG-b.
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The study's findings underscore the quantifiable benefits of integrating biophilic design principles into office spaces, emphasizing their potential to promote employee well-being and reduce stress. Further research is encouraged to explore the long-term effects of such interventions and their broader implications for organizational outcomes.
Allostasis and Allostatic Load
The concept of allostasis elucidates the intricate interplay between various psycho-physiological states within the human body. When individuals encounter stressors, their bodies undergo a range of effects and adaptations, contingent upon the magnitude of stress endured. McEwen defines allostatic load as "the price the body pays for being compelled to adapt to adverse psychosocial or physical circumstances," representing either an excessive burden of stress or an inefficient operation of the stress hormone response system (McEwen, 2000). Biophilic research often stems from the premise of allostatic load, recognizing the fluctuating levels of stress within the body. Homeostasis serves as the default regulatory system, capable of adjusting to lower stress levels. However, when allostatic load surpasses the homeostatic range, the body's capacity to manage stress becomes compromised.
Allostatic load has been extensively studied and documented to exert adverse effects on both mental and physical health. Regarding mental health, Guidi et al. found elevated levels of allostatic load among individuals diagnosed with personality disorders, post-traumatic stress disorder, psychotic disorders, and severe alcohol dependence (Guidi et al.). Similarly, numerous physical conditions correlate with heightened allostatic load. Individuals with unhealthy lifestyles, characterized by factors such as obesity, poor sleep quality, and elevated rates of alcohol and tobacco use, often exhibit increased allostatic load (Guidi et al.). Furthermore, the accumulation of stress can precipitate the onset of various physical ailments. Guidi's research identified a significant association between certain diseases, such as type 2 diabetes, musculoskeletal disorders, neurological disorders, cardiovascular diseases, and elevated allostatic load levels (Guidi et al.). This cyclical relationship underscores the reciprocal influence between allostatic load and physical health conditions.
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Prolonged exposure to escalating stress levels may culminate in what Cleo Valentine and other researchers define as allostatic overload, wherein chronic or recurrent stressors overwhelm the body's regulatory systems (Valentine, 2023). Allostatic overload, frequently reported as a psychosomatic syndrome according to the Diagnostic Criteria for Psychosomatic Research (DCPR), serves as a robust indicator of pre-existing or developing physical conditions (Fava & Guidi). Architecture, as a form of art, encompasses subconscious imagery that can evoke profound psychological responses. Biophilic elements in design offer a restorative effect, mitigating allostatic load by reducing the body's stress response. Valentine posits that exposure to biophilic architecture counteracts the stress-inducing effects of sterile, imposing structures associated with power and authority. Chronic exposure to biophilic environments becomes imperative to counterbalance external stressors, offering a necessary reprieve from allostatic overload.
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While measuring psychological states often lacks linearity, allostatic load provides a concrete metric for assessing physiological stress levels. McEwen emphasizes quantifiable measures such as cardiovascular activity, metabolism, and levels of adrenaline and cortisol in blood samples as reliable indicators of stress and potential health outcomes (McEwen, 2000). The restorative influence of biophilia on brain stability is increasingly recognized as a statistically significant measure. Joung et al. conducted a study assessing physiological changes in the prefrontal cortex of young adults exposed to "forest" versus "urban" environments. Prefrontal cortex activity, governing thoughts and emotions closely linked to stress, exhibited lower concentrations of total hemoglobin and oxyhemoglobin when individuals viewed forest scenery, indicative of reduced stress levels (Joung et al., 2015). This study underscores the stress-reducing effects of biophilic elements, contributing to a more relaxed prefrontal cortex.
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In summary, the concept of allostatic load offers a comprehensive framework for understanding the intricate relationship between stress and its physiological and psychological ramifications. Biophilic design emerges as a potent tool for mitigating allostatic overload, promoting mental and physical well-being through the creation of restorative environments.
Architectural view: The Practice of Biophilic Design by Stephen R. Kellert
In his book on Biophilic design, he characterizes biophilia as “a diverse set of inclinations to affiliate with natural patterns and processes.” and then later extends this definition into his perspective on implementing this into the built environment. He defines biophilic design in relation to 9 conditions he determines necessary for the application of a biophilic design.
Kellert’s illustration of how he connects Biophilia to Biophilic design and application.
Biophilic design, as Kellert describes it, is very conservative, and design that fulfills all of his 9 principles will as far as the research shows result in the demonstrated physiological and psychological changes outlined.Â
Conclusion
Ultimately, biophilia, the integration of nature into architectural design, aims to enhance the well-being of individuals who inhabit or experience these spaces. Extensive research indicates that biophilia exerts a profound influence on both the psychological and physical states of perceivers. Psychological assessments, including the Profile of Mood States, State-Trait Anxiety, Restoration Outcome Scale, and Comfort rating, consistently reveal significant improvements in anxiety reduction, mood enhancement, and restoration outcomes when biophilia is introduced. Similarly, various physiological measures such as heart rate variability, salivary sampling, EEG brainwave measurement, and electrodermal activity demonstrate tangible enhancements in physical well-being in response to biophilic stimuli. These include reduced physical stress responses, restorative effects, and expedited stress recovery processes. Allostatic load serves as a pivotal concept bridging the gap between the physical and psychological realms, representing the potential intersection where the positive impacts of biophilia manifest. Elevated levels of allostatic load can detrimentally affect both the physical and mental states of individuals, highlighting the significance of implementing biophilic design interventions to mitigate these effects and promote overall well-being. Thus, biophilia emerges as a compelling approach to fostering harmony between the psychological and physical aspects of human experience within architectural environments.
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