The term "biophilia" (from Greek bios: life, philia: love) was coined by biologist E.O. Wilson in 1984 in his eponymous book to describe what Wilson called "the innate tendency of human beings to seek connections with other forms of life." It's not a romantic idea—it's an evolutionary hypothesis. Humans evolved for over 200,000 years in natural environments (savannas, forests, waterways). Our nervous system developed in this context. The physiological well-being response to contact with nature is, according to the biophilic hypothesis, an evolutionarily programmed adaptive response.

Scientific Evidence: Nature and Stress Reduction

Research on biophilia has produced solid evidence in three main areas: physiological response, psychological response, and recovery from illness. Roger Ulrich's study (1984, Science): one of the most cited studies in environmental psychology. Ulrich compared post-operative recovery in hospital patients in rooms with windows facing a brick wall versus rooms with windows overlooking a grove of trees. Results: patients with a view of trees had shorter average hospital stays (7.96 vs 8.70 days), used fewer painkillers (fewer doses of analgesics), and received fewer negative evaluations from nurses. A window overlooking trees produced measurable effects on physiological recovery. Physiological measurements: subsequent research directly measured physiological responses to contact with nature. Viewing or immersion in natural environments (forests, parks, gardens) versus urban environments (streets, buildings) produces: reduction in salivary cortisol (a stress marker) of 12-20%, reduction in heart rate of 4-8%, reduction in systolic blood pressure of 4-6 mmHg, increased parasympathetic nervous system activity (HRV: heart rate variability, a marker of relaxation), reduced amygdala activation: functional magnetic resonance imaging (fMRI) shows reduced amygdala activation (the brain's fear and stress center) in people viewing natural images versus urban images (Bratman et al., 2015). A study by Bratman et al. (PNAS, 2015) showed that a 90-minute walk in a natural environment (compared to an urban environment) reduced mental rumination (the negative repetitive thinking associated with depression) and neural activation in the subgenual prefrontal cortex (an area associated with depression).

Preference for "Savanna-Like" Landscapes: The Evolutionary Hypothesis

If biophilia is an evolutionary adaptation, we should have specific preferences for the types of landscapes in which our ancestors evolved. The savanna hypothesis (Appleton, 1975; Kaplan and Kaplan, 1989): humans evolved primarily in the African savanna. The landscapes they prefer tend to have characteristics typical of favorable savanna: open space with broad visibility (to detect predators), few isolated trees with wide, horizontal canopies (to shelter beneath), presence of water (an indicator of available resources), moderate visual complexity (not too simple to be boring, not too complex to be threatening). Experimental tests: Heerwagen and Orians (1993) showed photographs of African savannas, dense forests, open grasslands, and deserts to subjects from diverse cultures (Europe, Asia, Africa): the universal preference was for savanna-like landscapes, regardless of culture. Even children aged 2-3 years (too young to have internalized cultural preferences) showed preferences for trees with wide horizontal canopies (typical of savannas) over trees with narrow vertical canopies. Preferences for water: the presence of water (lakes, rivers, sea) universally increases landscape preference. This preference is so strong that water is systematically incorporated into urban parks worldwide (fountains, ponds, canals). Italian gardens and English parks: both historical garden styles (despite their stylistic differences) incorporate basic biophilic elements: open space, isolated trees, water, moderate complexity. Not by chance: garden designers instinctively satisfied the biophilic preferences that visitors wanted to experience.

Attention Restoration Theory (ART) and the Forest as Therapy

Rachel and Stephen Kaplan (1989) proposed "Attention Restoration Theory" (ART) to explain why contact with nature improves cognition and reduces mental stress. The mechanism: modern life requires "directed attention" (focused attention): voluntary concentration on specific tasks that demands cognitive effort and becomes exhausted over time (mental fatigue). Natural environments capture "involuntary attention" (fascination: the passive pleasure of watching a stream, falling leaves, flying birds): a type of attention that doesn't become exhausted but rather regenerates, allowing the directed attention system to recover. The four elements of the restorative environment (Kaplan): being away (sense of psychological distance from daily stress: the forest is "another place"), fascination (involuntary interest in natural elements: water, animals, plant forms), extent (the feeling of being in a coherent and vast entity that extends beyond immediate sight), compatibility (congruence between the environment and one's goals: the forest requires nothing, it adapts to any purpose). Evidence for ART: students exposed to 10-15 minutes of views of trees and gardens between mental tests showed better results on subsequent tests compared to students exposed to urban views. Workers with windows overlooking greenery had fewer sick days and reported greater job satisfaction. Children with ADHD showed symptom reduction (inattention, hyperactivity) after outdoor activities in natural environments compared to urban environments (Taylor et al., 2001).

Biophilic Design: Bringing Nature into Architecture

Biophilic design is the discipline that applies biophilia principles to architecture and interior space design. The goal: to design buildings and spaces that meet the biophilic needs of occupants, improving well-being, productivity, and health. The 14 patterns of biophilic design (Browning, Ryan, Clancy 2014): nature in the space (living plants, water, natural light, views of nature), natural analogies (materials, textures, colors, forms that evoke nature: wood, stone, fractal patterns), nature of space (open perspective, refuge, sense of mystery that invites exploration). Applications in office design: offices with biophilic design (plants, natural light, natural materials) show: increased worker productivity of 6-15% (Human Spaces Report 2015 data), reduced absenteeism of 10-15%, improved self-reported well-being of 15%, increased creativity of 15%. "Living walls" (green walls): systems of vertical vegetation inside buildings. Beyond the aesthetic effect, living walls reduce dust in the air, buffer temperature and humidity fluctuations, reduce noise, and produce measurable positive psychological effects. Biophilic schools: school environments with access to green spaces and natural elements indoors show improved learning, reduced mental fatigue, and fewer behavioral problems. The review by Kuo et al. (2019) analyzed 100 studies on the impact of nature on school learning, finding consistent positive effects. Biophilic hospitals: more and more hospitals are integrating healing gardens, windows overlooking greenery, natural materials, and plants in common areas to accelerate patient recovery (building on evidence such as Ulrich's 1984 study).