NC State researchers randomly assigned students to sit for 10 minutes in either a restored forest or a busy urban area while listening to birdsong or traffic through noise-cancelling headphones. The combination of a restored forest and birdsong produced the largest reductions in stress and the biggest increases in positive emotion; traffic in the city produced the worst outcomes. Mixed pairings produced intermediate results, suggesting both environment and sound independently matter. The study suggests adding natural sounds to urban spaces may help reduce stress.
Birdsong in a Restored Forest Cuts Stress and Boosts Mood, NC State Study Finds
A study found that people who listened to the sound of birdsong felt their mood improve, compared to traffic sounds. Patrick Pleul/dpa
Researchers at North Carolina State University found that a short, 10-minute combination of being in a restored forest and listening to birdsong produced the largest reductions in self-reported stress and the biggest increases in positive mood.
The study recruited students from NC State's College of Natural Resources. Participants sat for 10 minutes in one of two campus locations while wearing noise-cancelling headphones: a replanted, restored forest beside a creek or a busy urban area outside the Talley Student Union. Through the headphones they heard either recorded birdsong or recorded traffic noise. Both the physical location and the audio stream were randomly assigned so the researchers could measure the independent effects of environment and sound.
The restored forest had more than 70% tree cover and no visible buildings; participants faced the trees. The urban site was dominated by buildings and concrete with only sparse greenery.
After each session participants completed brief self-reports assessing perceived stress, positive and negative emotions, and how mentally refreshed or "restorative" they felt.
Key Findings
Of the four tested combinations, the restored forest paired with birdsong produced the most favorable outcomes: the lowest stress levels, the fewest negative emotions, the most positive emotions, and the greatest sense of mental restoration. By contrast, traffic noise in the urban setting produced the worst outcomes across those same measures.
The two mixed conditions—birdsong in the city and traffic noise in the forest—yielded intermediate results, indicating that both the visual/physical environment and the auditory environment independently influence mood and stress. Together they deliver the strongest benefit.
"For participants who were in a green space listening to the birds, there were significant effects. Positive emotions went up, negative emotions went down, stress went down, and perceptions of feeling restored went up more than any other combination. On the other hand, you had the complete opposite when participants in a gray, urban area listened to the sounds of cars, and more mixed reactions when the sounds and areas were mismatched," said study author Nils Peterson.
The authors suggest practical implications: adding natural sounds to stressful urban spaces—through landscaping, water features, or ambient sound design—could help reduce the negative effects of urban noise. They also note that other natural acoustic elements, such as water sounds, have been shown in previous literature to be restorative.
While the study used a convenience sample of college students and relied on short, 10-minute exposures and self-reported measures, the randomized design provides clear evidence that both setting and sound independently affect short-term stress and mood. The findings support further research into how urban design and soundscapes can be optimized to improve public mental health.
Help us improve.
