Benefits of bird song reduced due to traffic noise

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.  

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. 

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. 

Notes to editors 

• For more information and to bid for an interview with Dr Marselle or Dr Ratcliffe, please contact mediarelations@surrey.ac.uk 

• Paper title: 'The influence of acoustic characteristics and anthropogenic noise on restorative perceptions of natural soundscapes' DOI: 10.1002/pan3.70405.