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#BrownNoise – why brown noise is said to be soothing

26.2.2023

Translation: Veronica Bielawski

The #brownnoise hashtag has garnered over 100 million views on TikTok. Since summer 2022, people with ADHD in particular have increasingly been swearing by brown noise and its calming effect. It’s time to get to the bottom of this trend.

A dull, deep noise is causing a big stir on social media. This downbeat sound also offers a lot of room for interpretation. Some say it sounds like an aeroplane turbine, others claim it’s more like a room humidifier. Others still are reminded of the sound of the sea or a faraway waterfall.

Whatever the case, the sound being referred to is brown noise, also called red noise. On TikTok, it’s been trending since the summer of 2022. The hashtag #brownnoise has already garnered 106 million clicks – and on YouTube, twelve-hour brown noise videos have millions of views. Brown noise is going viral, in particular among the ADHD (attention deficit hyperactivity disorder) community on TikTok. They attribute a variety of positive effects to the subdued, low-pitched noise. Reportedly, it brings about better focus and calmer thoughts, helps you fall asleep and can silence tinnitus. One user writes in her video, «I can’t stop listening – my brain has never been so quiet.»

So, what exactly is brown noise? How does it differ from the better-known white noise? And what does the science say: does the noise really have the potential to offer relief from ADHD, concentration disorders and sleep problems?

Hearing in colour – the rainbow of sound

First off, why are certain sounds called brown (or red) noise, while others are termed pink noise, and others still white noise? What it comes down to is that the human ear can perceive a certain range of frequencies – ones that cause the cochlea in the inner ear to vibrate. Scientists finally agreed to name the range of audible frequencies after colours. Depending on the intensity of the high and low frequencies of a sound, it’s referred to as white, pink, purple, grey or brown noise.

Now, people using sound to improve their focus or to help them fall asleep is nothing new. Parents read bedtime stories to their kids, and there are entire channels of hours-long educational music videos on YouTube. It was only a matter of time before abstract sounds, like brown noise, would be launched from acoustic niche to TikTok star. But what exactly is brown noise?

Brown, pink and white noise – what exactly is it?

Where the idea of naming frequencies after colours came from isn’t exactly known. Brown noise, in any case, was named not after the colour, but after Scottish botanist Robert Brown. Under the microscope, he observed how pollen grains in liquid dance jerkily, so to speak, and termed this movement Brownian motion. Just like the pollen’s movement, the frequencies of static noise are perceived as random.

Brown, white and pink noise differ in the intensity of their frequencies. In brown noise, for example, the high, rather unpleasant frequencies are reduced, while low frequencies are amplified. This creates a deep, calm, and quietly rumbling noise reminiscent of a gust of wind or a nearby river.

In white noise, all frequencies are played at the same intensity. This gives the noise a high-pitched, hissing sound and is reminiscent of a tube TV with poor reception. Many people experience white noise as unpleasant, as the high frequencies can be irritating.

Pink noise is somewhere between white and brown noise; high frequencies are only slightly reduced and low frequencies are amplified. So, pink noise has neither the hissing sound of white noise nor the rumbling sound of brown noise. It’s reminiscent of gentle rainfall.

All of them (as well as related colour sounds like grey or purple noise) are said to have positive effects on concentration, sleep and relaxation. So far, these effects have mainly been scientifically proved for white noise.

White noise for concentration difficulties and ADHD

It’s no coincidence that TikTok users with ADHD in particular have jumped on the #brownnoise trend by the millions. The scientific assumption is that this type of sound – be it white or brown noise – pushes disruptive noise into the background, allowing the individual to think more clearly.

Researcher Göran Söderlund of Western Norway University of Applied Sciences has conducted 15 studies on the effects of white noise on people with ADHD. His conclusion? The positive effects of the different colour sounds go far beyond simply drowning out noise.

In one of his studies, Söderlund showed clear positive effects of white noise on reading ability and memory performance of children with reading difficulties. Other studies support his findings. For example, a study carried out under Ephraim Rosalez’s leadership, published in the journal Child & Family Behavior Therapy found that white noise promotes the ability to concentrate in children with ADHD.

A few years later, similar results were published in the International Journal of Environmental Research and Public Health. In the study, children with ADHD had to solve tasks with white noise, with music and without background noise. Again, the results showed that the children were able to focus best with white noise. Focus was weakest in the quiet classroom with no auditory stimulus.

The reason why this type of sound is perceived as pleasant and conducive to concentration, especially by people with ADHD, could lie in their anatomy. In one of his studies, Söderlund states that people with ADHD have stronger brainstem responses to auditory stimuli. Exposure to monotonous noise could calm these responses.

But even for adults without ADHD, colour sounds can have a concentration-enhancing effect – so says a study in the journal Noise & Health. Subjects listened to brown, white, pink and no noise while they worked. The results were clear: white, pink, and brown noise had a significant positive effect on memory performance, work speed and general performance at work, compared to complete silence. The researchers conclude, «It is feasible, in the future, to use knowledge of colour noises to improve productivity in a workplace with a healthy environment.»

Colour sounds for sleep problems

Whether sounds of any kind are conducive to falling asleep is a matter of controversy. Authors of a literature review of 38 studies published in Sleep Medicine Reviews challenged the notion that white noise helps people fall asleep. The findings state, «... the quality of evidence for continuous noise improving sleep was very low ...»

On the other hand, a research group in the Journal of Theoretical Biology came to a different conclusion. They studied the effect of pink noise on sleep quality and observed that subjects had deeper sleep and found better ways of dealing with sleep interruptions with said noise.

The potential and limitations of the TikTok trend

Colour sounds have a positive effect on our concentration and can offer relief from ADHD. Study results suggest that continuous sounds, such as white, pink and brown noise, can improve focus and make it easier to fall asleep.

On the other hand, there’s no clear evidence that red noise is effective against stress or that it can silence tinnitus, as is often touted under the hashtag #brownnoise.

In general, most studies – especially those on ADHD – deal with white noise. These results can’t simply be applied to all other colour sounds.

What does this mean for the TikTok trend? Well, if you find brown noise helpful for achieving a state of relaxation, learning more efficiently, stopping spirals of thought or for simply fantasising about the ocean – go for it. If not, go ahead and enjoy the silence.

Header image: John O'Nolan via unsplash

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Olivia Leimpeters-Leth

Autorin von customize mediahouse

oliver.fischer@digitecgalaxus.ch

I'm a sucker for flowery turns of phrase and allegorical language. Clever metaphors are my Kryptonite – even if, sometimes, it's better to just get to the point. Everything I write is edited by my cat, which I reckon is more «pet humanisation» than metaphor. When I'm not at my desk, I enjoy going hiking, taking part in fireside jamming sessions, dragging my exhausted body out to do some sport and hitting the occasional party.

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