Summary: Researchers have conducted a comprehensive meta-analysis confirming that exposure to nature—whether real, virtual, or even imagined—significantly reduces negative emotions and boosts brain health. The team reviewed 33 studies involving over 2,100 participants to map the neurophysiological impact of “green time.”
Using tools like EEG and fMRI, the study found that nature exposure creates a more balanced psychological state. As 90% of the U.S. population is expected to live in urban areas by 2050, the researchers argue that “Nature Prescriptions” (Nature Rx) should become a cornerstone of urban design and public health to protect our collective “brain capital.”
Key Facts
- The “Brain Capital” Concept: Nature exposure is now viewed as a critical determinant of brain health, essential for maintaining the cognitive and emotional resources of a population.
- Multimodal Benefits: Positive effects were observed across various types of exposure, including outdoor walking, virtual reality (VR) nature environments, and even simply looking at images of the natural world.
- EEG Insights: Electroencephalogram (EEG) data showed that nature exposure directly correlates with a reduction in negative emotional processing and an increase in positive psychological responses.
- Urban Priority: With increasing urbanization, the researchers emphasize that environmental factors—not just genetics—play a massive role in shaping mental health risks and resilience.
Source: University of Houston
You probably heard it from your mom a thousand times – fresh air and sunshine; it’s the cure for most anything.
Now scientists at the University of Houston concur, measuring the impact of mother’s advice on mother nature to find that exposure to nature is associated with reductions in negative emotions.
Given that nearly 90% of the U.S. population is projected to reside in urban areas by 2050, researchers say integrating nature into urban design and public health initiatives is an increasingly recognized national public health and economic priority for improving emotional wellbeing.
“Findings from this systematic review support the notion that nature exposure is a critical determinant of brain health and therefore brain capital. Thus, promoting and maintaining healthy environments is critical to promote and grow the world’s brain capital,” said renowned brain scientist Jose Luis Contreras-Vidal, Hugh Roy and Lillie Cranz Cullen Distinguished Professor of Electrical and Computer Engineering and director, NSF IUCRC BRAIN Center (Building Reliable Advances and Innovation in Neurotechnology). He led a team of researchers through a systematic review and meta-analysis of the impact of nature on wellness.
The team examined the results from 2,101 participants in 33 studies combining neuroimaging and psychological assessments during exposure to real, virtual or imagined natural environments. EEG was the most widely used neuroimaging modality across the studies reviewed.
“Healthy populations showed a more balanced psychological response, with nature exposure being associated with both increases in positive emotions and reductions in negative emotions,” reports Contreras-Vidal in the International Journal of Environmental Research and Public Health.
“Growing interest in how nature influences the brain has driven research toward understanding its neurophysiological impact. This interest has recognized that genetics alone cannot account for health risk factors and that environmental exposures play a substantial role in shaping brain health.”
The team examined brain studies that included several different tasks:
- Imagery: The most popular task across studies, images of nature consistently demonstrated significant effects of nature on well-being. Eight studies reported increases in positive emotions while seven observed decreases in negative emotions.
- Virtual Reality: Eight studies implemented VR-based exposure to nature, all of which used EEG as their neuroimaging modality. Six studies reported decreases in negative emotions and five reported increases in positive emotions.
- Walking Outdoors: Five studies reported an increase in positive emotions and four reported decreases in negative emotions.
While studies employing psychological and neuroimaging can potentially provide a shift in understanding of the neurophysiological impact of nature on brain health and wellness, there is still much to know, and Contreras-Vidal has suggestions.
“EEG studies should expand their scope to incorporate neural metrics like functional connectivity, while prioritizing standardization of real-world multimodal data for study comparisons and effective inclusion of AI,” he said.
“Ultimately, the goal is to design Nature prescriptions (Nature Rx) to promote brain health and treat mental illnesses across the lifespan,” said Contreras-Vidal.
Based on the findings, the BRAIN Center is working on a study on the neural mechanisms underlying nature’s impact on brain health and wellness in Houston’s Third Ward neighborhood along the green corridor and on the UH campus’ pollinator gardens.
Key Questions Answered:
A: While a real walk is ideal, the study found that even imagery and virtual reality nature experiences significantly decreased negative emotions. Your brain responds to the visual cues of nature even when you can’t get outside.
A: It’s a term scientists use to describe the collective brain health and cognitive skills of a community. Protecting it means ensuring people have environments that reduce stress and promote healthy neural function—like parks and green spaces.
A: Yes. The meta-analysis showed that VR-based nature exposure consistently improved mood and reduced anxiety. This could be a game-changer for people in high-density cities or those with limited mobility.
Editorial Notes:
- This article was edited by a Neuroscience News editor.
- Journal paper reviewed in full.
- Additional context added by our staff.
About this neurology and aging research news
Author: Laurie Fickman
Source: University of Houston
Contact: Laurie Fickman – University of Houston
Image: The image is 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 nature has been associated with benefits to human well-being, commonly evaluated using standardized psychological assessments and, more recently, neuroimaging modalities such as Electroencephalography (EEG), functional Magnetic Resonance Imaging (fMRI), and functional Near-Infrared Spectroscopy (fNIRS).
This systematic review and meta-analysis addresses the following questions. (1) How is the impact of nature on well-being studied using psychological and neuroimaging modalities and what does it reveal? (2) What are the challenges and opportunities for the deployment of wearable neuroimaging modalities to understand the impact of nature on the brain’s health and well-being?
A search on PubMed, IEEE Xplore, and ClinicalTrials.gov (March 2024) identified 33 studies combining neuroimaging and psychological assessments during exposure to real, virtual or imagined natural environments. Studies were analyzed by tasks, populations, neuroimaging modality, psychological assessment, and methodological quality. Most studies were conducted in Asia (n = 23 or 70%).
Healthy participants were the dominant target population (70%). In total, 61% of the studies were conducted in natural settings, while 39% used visual imagery. EEG was the most common modality (82%). STAI (n = 8) and POMS (n = 8) were the most common psychological assessments.
Only seven studies included clinical populations. Two separate meta-analyses of nine studies with explicit experimental and control groups revealed a significant positive effect of nature exposure on psychological outcomes (Hedges’ g = 0.30; p = 0.0021), and a larger effect on neurophysiological outcomes (Hedges’ g = 0.43; p = 0.0004), both with moderate-to-high heterogeneity.
Overall, exposure to nature was associated with reductions in negative emotions in clinical populations. In contrast, healthy populations showed a more balanced psychological response, with nature exposure being associated with both increases in positive emotions and reductions in negative emotions.
Notably, 88% of the studies presented methodological weaknesses, highlighting key opportunities for future neuroengineering research on the neural and psychological effects of nature exposure.
