Birdsongs alleviate anxiety and paranoia in healthy participants.

The present study investigated the effect of urban (traffic noise) vs. natural (bird songs) soundscapes on mood, state paranoia, and cognitive performance, hypothesizing that bird songs lead to significant improvements in these outcomes. An additional goal was to examine the differential impact of lower vs. higher diversity of the soundscapes by manipulating the number of different typical traffic sounds or songs of different bird species within the respective soundscapes. In a randomized online experiment, 295 participants were exposed to one out of four conditions for six minutes: traffic noise low, traffic noise high, birdsong low, and birdsong high diversity soundscapes. Before and after the exposure, participants performed a digit-span and dual n-back task, and filled out depression, anxiety, and paranoia questionnaires. The traffic noise soundscapes were associated with a significant increase in depression (small effect size in low, medium effect size in high diversity condition). Concerning the birdsong conditions, depression exclusively decreased after exposure to the high diversity soundscape (small effect size). Anxiety and paranoia significantly improved in both birdsong conditions (medium effect size). For cognition, no effects were observed. In sum, the present study shows that listening to bird songs improves anxiety, while traffic noise is generally related to higher depressiveness, regardless of diversity. Moreover, for the first time, a beneficial, medium-sized effect of a natural birdsong soundscape was demonstrated for paranoia, which bears interesting implications for further research in paranoia-prone individuals or even psychiatric samples.