The psychological benefits of hearing birdsong, which include stress reduction and positive mood changes, are being threatened by traffic noise, according to a new study published in People and Nature. Researchers found that even low levels of traffic noise negatively impacted the wellbeing benefits derived from natural sounds.
Dr. Eleanor Ratcliffe, associate professor in environmental psychology at the University of Surrey and co-author of the study, noted that bird sounds are often perceived as relaxing and psychologically beneficial. The study involved over 1,500 participants who listened to nine simulated soundscapes combining birdsong and traffic noise, then answered questions about their feelings.
While listening to birdsong was found to offer psychological benefits regardless of its acoustic characteristics, the presence of traffic noise consistently had a negative effect. Complementary heart rate measurements on a group of participants revealed significantly lower variability when traffic noise was present, indicating a greater physiological stress response.
The negative impact of traffic noise was more pronounced in soundscapes with high acoustic characteristics, which researchers suggested might be due to overstimulation. Younger participants reported higher feelings of wellbeing than older participants, possibly due to better hearing and an enhanced acoustic experience. Greater perceived diversity in birdsong also correlated with increased wellbeing, particularly for those with more knowledge of birds.