Being in nature improves one’s mental health
“When he fell in love with birds and began to photograph them, his anxieties dissipated. The sound of birdsong reminded him to look outwards at the world.”
― Kyo Maclear, Birds Art Life: A Year of Observation
Ever since Covid-19 exploded onto the scene, people have been experiencing increased anxiety, paranoia and depression. But according to two recently published companion studies by researchers at the Max Planck Institute for Human Development, listening to birdsong not only improves one’s mood but also minimizes anxiety and paranoia.
In the first of these two studies, lead author, cognitive neuroscientist Emil Stobbe, a Predoctoral Fellow working on his PhD, and his collaborators studied how traffic noise and birdsong affect mood, paranoia and cognitive functioning in individual people. To conduct this study, 295 study participants listened to either ordinary traffic noises or birdsongs from the local region at random for six minutes. These online sound clips featured either low or high diversity traffic noises or birdsongs to test whether the diversity of the soundscape itself played any role in the listeners’ moods (all sound clips are available here). Before and after listening to the sound clips, all study participants filled out questionnaires that assessed their mental health and tested their cognitive performances.
But why study mentally healthy volunteers?
“Everyone has certain psychological dispositions”, Mr Stobbe said in a statement. “Healthy people can also experience anxious thoughts or temporary paranoid perceptions. The questionnaires enable us to identify people’s tendencies without their having a diagnosis of depression, anxiety, and paranoia and to investigate the effect of the sounds of birds or traffic on these tendencies.”
The study revealed that listening to birdsong was beneficial; these sounds improved the study participants’ moods by reducing anxiety and depressive symptoms as well as paranoid symptoms, whereas traffic noises were not beneficial (Figure 1).
It’s interesting to note that, although birdsongs did not seem to reduce depressive symptoms, traffic noise — especially a high diversity of traffic noises — worsened depressive symptoms. Similarly, listening to traffic noise was not beneficial for other mental health issues, as it increased anxiety as well as paranoid symptoms in healthy study participants.
The researchers also found that neither birdsong nor traffic noise influenced cognitive performance.
This study is the first to discover what many of us have suspected: birdsongs reduce symptoms of paranoia. This benefit was independent of whether there was just one songbird species singing, or more than that.
“Birdsong could also be applied to prevent mental disorders”, Mr Stobbe pointed out. “Listening to an audio CD would be a simple, easily accessible intervention.”
Although Mr Stobbe and his collaborators did not find any effects upon cognitive performance from either birdsong or traffic noise, they noted that using birdsongs as a background soundscape could open new therapeutic possibilities in psychiatric hospitals, for example.
This study follows up on a 2021 study that I shared with you (more here) where people reported greater life satisfaction when there was a greater diversity of bird species living nearby. But why is simply hearing birdsongs so powerful, as this study suggests? The researchers think birdsong is a subtle indication of an intact natural environment that detracts our attention from stress that could otherwise signal an acute threat.
“But if we could already show such effects in an online experiment performed by participants on a computer, we can assume that these [effects] are even stronger outdoors in nature”, Mr Stobbe postulated.
But how are these effects being modulated in the brain? So far, no studies have investigated the relationship between natural and urban environments on stress-related brain responses. But a companion study co-authored by the research group’s leader, Simone Kühn, sought to explore this question further. To do this, Professor Kühn and her research team designed a study using fMRI to measure amygdala activation in 63 healthy participants, before and after a walk, using a fearful faces task and a social stress task (Figure 2).
The amygdala (from the Greek for ‘almond’) are small paired almond-shaped structures within the brain that are part of the limbic system, a neural network that mediates many aspects of emotion and memory. Originally, the amygdala was thought to be activated by fear and other emotions related to unpleasant events, but now we know it also plays a neural role in positive emotions. Previous research has shown that the amygdala is more activated during a stress task in urban compared to rural dwellers.
The walk itself for this study lasted one hour and took place in an urban (busy street) vs. natural environment (forest) (Figure 3).
“We were recently able to perform a study showing that a one-hour walk in nature reduces brain activity associated with stress”, summarized Professor Kühn in a statement. “We cannot say yet which features of nature — smells, sounds, color, or a combination thereof — are responsible for the effect.”
Nevertheless, these results suggest that going for a walk in nature can calm stress-activated brain regions and may thereby relieve some symptoms of mental strain and potentially even reduce the risk of developing a mental disorder.
Taken together, these two studies argue in favor of creating more green spaces in urban environments as a way to help urban dwellers cope with the stresses of city living. These studies are timely because, for example, the United Nations reported that 2007 was a tipping point where, for the first time in history, the majority of the world’s human population lived in urban areas (more here). That report went on to estimate that by 2050, 68% of the world’s total population will live in cities. But already, most people live in cities in some regions: across Europe, for example, the urbanization rate is as high as 75%.
“Urbanization coincides with increasing rates of mental illness”, the research team noted in their study. They pointed to a 2005 review that concluded that approximately 30% of the incidence in schizophrenia may be attributed to urban factors in interaction with genetic liability and social adversity.
Although it’s not yet clear precisely what aspect of nature (or birds) provides people with stress-reducing benefits, the findings of these companion studies suggest interesting avenues for further research such as the active manipulation of background noise in different situations or the examination of its influence on patients with diagnosed anxiety disorders or paranoia.
“What is clear is that nature improves mental health and well-being”, said Professor Kühn. “So let’s go for a walk in green surroundings.”
E. Stobbe, J. Sundermann, L. Ascone & S. Kühn (2022). Birdsongs alleviate anxiety and paranoia in healthy participants, Scientific Reports 12:16414 | doi:10.1038/s41598-022-20841-0
Sonja Sudimac, Vera Sale & Simone Kühn (2022). How nature nurtures: Amygdala activity decreases as the result of a one-hour walk in nature, Molecular Psychiatry | doi:10.1038/s41380-022-01720-6
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