Traffic noise disrupts recognised benefits of bird song and other sounds from nature, a new study from the University of Surrey reports.
During this study, Surrey researchers investigated the acoustic characteristics of natural soundscapes containing birds on psychological wellbeing and whether these wellbeing benefits would be impacted by traffic noise.
Natural soundscapes, such as bird song, have psychological benefits, including stress reduction and positive mood changes, whilst traffic noise has been shown to increase stress and annoyance. Researchers suggest reducing speed limits near parks to potentially lessen noise caused by traffic.
Dr Melissa Marselle, a Lecturer in Environmental Psychology at the University of Surrey, said:
"Being in nature and listening to its sounds is a natural way of improving wellbeing. People report feeling refreshed and having a renewed feeling of calmness after exposure to natural environments. With such profound benefits, it is important that we learn more about what it is about such sounds that prompts such feelings in a person. The number or types of birds singing could be important; so too could the acoustic characteristics, like how loud or complex or varied the soundscape is.
"However, the modern industrial world is noisy, so we need to investigate the impact of traffic noise on nature's sounds and if it counteracts their benefits. Our research could help identify tranquil outdoor spaces to help those who are feeling overwhelmed."
To learn more, researchers conducted two complementary studies. Over 1,500 participants took part in the first study, where they listened to nine simulated soundscapes of natural sounds and traffic noise that varied in both acoustic complexity and amplitude. Participants were then asked a series of questions about how relaxed and restorative they felt after listening to the sounds they had just heard. In the second study, 63 participants were invited into a laboratory environment and listened to the same nine soundscapes as those in the first study, whilst wearing a heart rate monitor.
Researchers found that listening to natural soundscapes containing birdsong had a psychological benefit to wellbeing, irrespective of its acoustic characteristics. However, traffic noise within natural soundscapes, even at levels below World Health Organisation guidelines for daytime vehicle traffic noise, negatively impacted the psychological benefits of nature's sounds. Heart rate variability was also significantly lower for participants when listening to natural soundscapes with traffic noise, indicating a greater physiological stress response to such sounds.
Interestingly, the negative effect of high traffic noise was more pronounced when the acoustic characteristics of soundscapes were also at high levels. Researchers suggest that this may be a result of overstimulation, with too much overall sound energy within the soundscape negatively impacting feelings of restorativeness.
Dr Eleanor Ratcliffe, Associate Professor in Environmental Psychology at the University of Surrey, said:
"Traffic noise undoubtedly impacts the psychological benefit of natural soundscapes. With urban planning now including more green spaces it is important that steps are taken so that people enjoy such areas to their fullest. Minimising traffic noise through the reduction of speed limits in streets close to parks or increasing greater density of ground level vegetation around park boundaries, could be ways to do this. It is important that people get to spend time in nature and are able to appreciate its benefits without being distracted by noise."
In addition to these findings, researchers also found that despite there being only three species of birds and five individual bird sounds in all soundscapes, participants reported greater feelings of wellbeing when they perceived greater species diversity (i.e. more types of birds). Researchers believe that perceptions of bird species richness are key for wellbeing benefits.
Due to the large number of participants across the two studies, researchers were also able to identify how different demographics responded to natural soundscapes. It was found that younger participants reported higher feelings of wellbeing compared to their older peers. Researchers theorise that this could be because younger participants have better hearing and subsequently may have had a higher quality acoustic experience of the soundscapes. It was also found that participants reporting greater knowledge of birds reported higher well-being and increased perceptions of bird diversity.
This study was published in the journal: People and Nature (Live will go live once embargo lifts)
