Summary: A comprehensive meta-analysis confirms that exposure to nature—whether real, virtual, or imagined—significantly lowers negative emotions and supports brain health. Researchers reviewed 33 studies with more than 2,100 participants to quantify the neurophysiological benefits of “green time.”
Using neuroimaging tools such as EEG and fMRI alongside standardized psychological assessments, the review indicates that nature exposure helps create a more balanced psychological state. With projections that nearly 90% of the U.S. population will live in urban settings by 2050, the authors argue that Nature Prescriptions (Nature Rx) and greener urban design should be public health priorities to protect collective brain health, or “brain capital.”
Key Facts
- Brain capital as a public health priority: Nature exposure is framed as a critical factor for maintaining cognitive and emotional resources across communities.
- Benefits across exposure types: Positive effects were recorded for outdoor walks, virtual reality nature environments, and even viewing images of natural scenes.
- EEG and emotion: Electroencephalography (EEG) evidence links nature exposure to reduced negative emotional processing and increased positive psychological responses.
- Urban implications: As cities grow, environmental factors such as access to green space exert major influence on mental health risks and resilience—beyond genetics alone.
Source: University of Houston
Remember what parents say about fresh air and sunshine? Science now quantifies that claim.
Researchers at the University of Houston conducted a systematic review and meta-analysis to measure how different forms of nature exposure affect emotional well-being and brain physiology. They found consistent evidence that exposure to natural environments lowers negative emotions and, in healthy populations, also increases positive emotions.
Given the expected surge in urbanization, the study emphasizes integrating natural spaces into city planning and public health strategies as a cost-effective way to promote mental wellness and preserve cognitive resources across populations.
Jose Luis Contreras-Vidal, Hugh Roy and Lillie Cranz Cullen Distinguished Professor of Electrical and Computer Engineering and director of the NSF IUCRC BRAIN Center (Building Reliable Advances and Innovation in Neurotechnology), led the team. “Findings from this systematic review support the notion that nature exposure is a critical determinant of brain health and therefore brain capital. Promoting and maintaining healthy environments is essential to grow global brain capital,” he said.
The analysis pooled data from 2,101 participants across 33 studies that combined neuroimaging and psychological measures while subjects experienced real, virtual, or imagined natural environments. EEG was the most common imaging tool used across studies.
Contreras-Vidal reported in the International Journal of Environmental Research and Public Health that healthy participants showed a balanced psychological response: nature exposure related to both increases in positive emotions and decreases in negative emotions. Clinical populations also showed measurable reductions in negative emotional states following nature exposure.
The review categorized study tasks and summarized consistent findings:
- Imagery: Viewing images of nature was the most common task. Eight studies reported increases in positive emotions and seven reported decreases in negative emotions.
- Virtual reality: Eight VR studies—each using EEG—mostly found reductions in negative emotions (six studies) and increases in positive emotions (five studies).
- Outdoor walking: Among studies of walking in natural settings, five reported increases in positive mood and four reported decreases in negative emotions.
Despite these encouraging results, the authors note significant methodological variability across studies. Most research (88%) showed weaknesses that limit direct comparisons. The reviewed studies were geographically concentrated (70% in Asia), primarily used healthy participants (70%), and favored EEG (82%) over other neuroimaging modalities. Common psychological measures included the STAI and POMS.
Contreras-Vidal recommends that future EEG research expand to include metrics such as functional connectivity and employ standardized, multimodal real-world data protocols. He also highlights the role artificial intelligence can play in harmonizing datasets and extracting robust biomarkers of nature’s effects on the brain.
“Ultimately, the goal is to design Nature prescriptions (Nature Rx) that promote brain health and help treat mental illnesses across the lifespan,” Contreras-Vidal said. To that end, the BRAIN Center is planning a study of the neural mechanisms behind nature’s benefits in Houston’s Third Ward, focusing on a local green corridor and the University of Houston’s pollinator gardens.
Key Questions Answered:
A: A real walk in nature is ideal, but the meta-analysis shows that imagery and virtual reality nature experiences also significantly reduce negative emotions. Visual cues alone can elicit meaningful brain responses.
A: Brain capital refers to the collective cognitive, emotional, and neural health of a community. Protecting it involves creating environments—parks, green corridors, and accessible nature—that reduce stress and support healthy brain function.
A: Yes. The review found consistent mood improvements and anxiety reductions from VR-based nature exposure, suggesting promise for therapeutic use in dense urban settings or for people with limited mobility.
Editorial Notes:
- Article edited by a Neuroscience News editor.
- Journal paper reviewed in full by the editorial team.
- Additional context added by staff for clarity and relevance.
About this neurology and aging research news
Author: Laurie Fickman
Source: University of Houston
Contact: Laurie Fickman, University of Houston
Image: Image credited to Neuroscience News
Original Research: Closed access. “A Systematic Review and Meta-Analysis of EEG, fMRI, and fNIRS Studies on the Psychological Impact of Nature on Well-Being” by Alexandra Daube, Yoshua E. Lima-Carmona, Diego Gabriel Hernández Solís, and Jose L. Contreras-Vidal. International Journal of Environmental Research and Public Health. DOI: 10.3390/ijerph23030377
Abstract
A Systematic Review and Meta-Analysis of EEG, fMRI, and fNIRS Studies on the Psychological Impact of Nature on Well-Being
Exposure to natural environments has been linked to benefits for human well-being, measured through psychological assessments and neuroimaging methods such as electroencephalography (EEG), functional MRI (fMRI), and functional near-infrared spectroscopy (fNIRS). This systematic review and meta-analysis examined how psychological and neuroimaging modalities are used to study nature’s effects and identified challenges and opportunities for wearable neuroimaging in real-world settings.
A literature search (March 2024) identified 33 studies that combined neuroimaging with psychological assessments during exposure to real, virtual, or imagined natural environments. Studies were analyzed by task type, population, imaging modality, psychological measures, and methodological quality. Most studies (70%) were conducted in Asia. Healthy participants dominated the sample (70%), 61% of studies occurred in natural settings, and EEG was the predominant modality (82%).
Meta-analyses of studies with explicit experimental and control conditions found a modest but significant positive effect of nature on psychological outcomes and a larger effect on neurophysiological outcomes, both with moderate-to-high heterogeneity. Overall, nature exposure was associated with reduced negative emotions in clinical groups and a combination of increased positive emotions and reduced negative emotions in healthy populations. The review also highlights widespread methodological weaknesses and areas for improvement in future research.