Investigators found that people who listened to recordings of birds singing experienced a significant reduction in anxiety and paranoia. In contrast, the researchers also found that recordings of traffic noises, including car engines, sirens, and construction, increased depressive states.
“The results suggest that it may be worthwhile to investigate the targeted use of natural sounds such as birdsong in a clinical setting – for example, in hospital waiting rooms or in psychiatric settings,” study investigator Emil Stobbe, MSc, a predoctoral fellow at the Max Planck Institute for Human Development, Berlin, said in an interview.
“If someone is seeking an easily accessible intervention to lower distress, listening to an audio clip of birds singing might be a great option,” he added.
The study was published online in Scientific Reports.
Nature’s calming effect
The aim of the research was “to investigate how the physical environment impact brain and mental health,” Mr. Stobbe said.
Mr. Stobbe said that there is significantly more research examining visual properties of the physical environment but that the auditory domain is not as well researched, although, he added, that the beneficial effects of interactions with nature are “well studied.”
He noted that anxiety and paranoia can be experienced by many individuals even though they may be unaware that they are experiencing these states.
“We wanted to investigate if the beneficial effects of nature can also exert their impact on these states. In theory, birds can be representational for natural and vital environment, which, in turn, transfer the positive effects of nature on birdsong listeners,” he said.
A previous study compared nature versus city soundscape conditions and showed that the nature soundscape improved participants’ cognitive performance but did not improve mood. The present study added diversity to the soundscapes and focused not only on cognition and general mood but also on state paranoia, “which can be measured in a change-sensitive manner” and “has been shown to increase in response to traffic noise.”
The researchers hypothesized that birdsong would have a greater beneficial effect on mood and paranoia and on cognitive performance compared with traffic noise. They also investigated whether greater versus lower diversity of bird species or noise sources within the soundscapes “would be a relevant factor modulating the effects.”
The researchers recruited participants (n = 295) from a crowdsourcing platform. Participants’ mean age was late 20s (standard deviations ranged from 6.30 to 7.72), with a greater proportion of male versus female participants.
To be included, participants were required to have no history of mental illness, hearing difficulties, substance/drug intake, or suicidal thoughts/tendencies.
The outcomes of interest (mood, paranoia, cognitive performance) were measured before and after soundscape exposure and each soundscape had a low- versus high-diversity version. This resulted in several analyses that compared two types of sounds (birdsongs vs. traffic noise) x two levels of diversity (low vs. high diversity) and two time points (pre- vs. post exposure).
The exposure to sounds lasted for 6 minutes, after which they were asked to report (on a 0-100 visual scale) how diverse/monotone, beautiful, and pleasant they perceived the soundscape to be.