Traffic noise cancels birdsong mood boost

The psychological benefits of hearing birdsong are diminished by traffic noise, according to a new study from the University of Surrey. The research, involving more than 1,500 participants, found that even low levels of traffic sound negatively affected the wellbeing otherwise derived from natural sounds.

Dr Eleanor Ratcliffe, an associate professor in environmental psychology at the University of Surrey and co-author of the study published in People and Nature, explained the focus. "Bird sounds tend to be one of the elements of nature soundscapes that people perceive as being most relaxing, most pleasant, beneficial for them psychologically," she said.

Study design and findings

Participants listened to nine simulated soundscapes combining birdsong and traffic noise and reported on their feelings. The study aimed to examine how different acoustic properties related to biodiversity might affect wellbeing and stress recovery.

However, the presence of traffic noise consistently reduced the psychological benefits. Analysis of heart rate measurements from a subgroup showed significantly lower variability for those hearing soundscapes with traffic noise. This indicates a greater physiological stress response. The negative effect was more pronounced in soundscapes with high levels of acoustic complexity, possibly due to overstimulation.

Interestingly, listening to birdsong itself provided a psychological benefit regardless of its specific acoustic characteristics. "It shows us that we should support and protect nature for the sake of nature, regardless of whether or not humans have some increased utility benefit from it," said Ratcliffe.

Variations in participant response

The research revealed differences in how people experienced the sounds. Younger participants reported higher feelings of wellbeing than older participants, which researchers suggested might stem from better hearing and a more enhanced acoustic experience.

Feelings of wellbeing also increased when participants perceived a greater diversity in the types of birds they were hearing. This effect was stronger for participants who claimed greater knowledge of birds, suggesting that the perception of bird species richness may itself boost the benefits.

Implications for design and individuals

The work has clear implications for urban planning, the researchers said. "With urban planning now including more green spaces it is important that steps are taken so that people enjoy such areas to their fullest," Ratcliffe noted.

Suggested measures to minimise traffic noise intrusion include reducing speed limits and increasing the density of ground-level vegetation around parks. At an individual level, Ratcliffe highlighted the accessibility of the activity. "Listening to birds is quite an accessible way to engage with nature." she added.

The study's complementary heart rate data provided concrete evidence of the stress induced by mixing natural and traffic sounds.