CNA – The sound of raindrops tapping on a window can be soothing for some, while others prefer a Lo-Fi playlist on Spotify to block out distractions.
ASMR triggers like ear brushing, whispering, and gentle tapping also provide pleasure for many. Different people find different sounds enjoyable, and the same noise can evoke varied responses depending on the situation.
For example, chewing sounds may cause irritation (misophonia) in one setting but be entertaining in mukbang videos at home.
This raises the question: What makes certain sounds soothing rather than irritating? More intriguingly, can you harness these sounds to enhance focus, improve sleep, or aid learning? Here’s a closer look.
FIRST, THE BRAIN
According to the chief wellbeing officer of Singapore Counselling Centre, Dr John Shepherd Lim, a few areas of the brain are activated when we engage in mental tasks such as reading, writing and analysing data. For instance, “the prefrontal cortex is heavily involved, particularly for decision making and attention”, he said.
Meanwhile, “the parietal lobes process sensory information, and handle numerical and mathematical processing”, said Dr Annabelle Chow, the principal clinical psychologist at Annabelle Psychology. The hippocampus is another important part as it provides “essential memory formation and retrieval”, she said.
What’s the point in knowing these various parts of your brain? “Sound can impact these areas by either enhancing or distracting focus, depending on its nature,” said Dr Lim.
Think about the times when soothing music helped you to concentrate on a report versus loud and unpredictable sounds disrupting your focus.
The hippocampus, one of the first regions of the brain to be ravaged by Alzheimer’s disease, is found to benefit from music, which “may increase neurogenesis in the hippocampus, allowing production of new neurons and improving memory”.
Studies also suggest that noise-induced stress may decrease dopamine availability in the prefrontal cortex. This results in decreased higher brain function and impaired learning and memory.
YOUR BUILT-IN NOISE CANCELLATION FUNCTION
If you’re wondering why you can ignore certain sounds in your office (the photocopier printing, general chatter, keyboards clacking etc) but not someone erratically tapping his pen next to you, that’s because the type of sound you hear can shift your brain’s focus, said Dr Chow.
Most of the time, your brain is in “selective attention” mode, which helps it to filter out unimportant sounds and lets you continue with your task, she said. “When we receive sound signals that are not relevant to our current focus, our brain detects them because they might be important or unexpected.
“If our brain decides the sound is important, our prefrontal cortex and parietal lobe shift our attention to the sound involuntarily,” said Dr Chow. In a way, it’s like deactivating your brain’s built-in noise cancellation function.
However, sound can also make it harder to focus as it competes for your attention, she said. How you’re feeling that day plays a part as well.
Generally, volume, pitch and rhythm play a role in how your brain reacts, said Dr Lim.
“For instance, high-pitched or loud noises might be irritating to some, while rhythmic or predictable sounds can help others concentrate by providing a steady auditory background.” Still, the reactions can vary from person to person “due to individual differences in auditory processing and personal preferences”, he said.
There are also those who require complete silence to work or study. “This need for silence may be due to heightened sensitivity to auditory stimuli, or a brain that is less adept at filtering out background noise,” said Dr Lim.
WHY YOU WORK BETTER OR FALL ASLEEP IN FRONT OF THE TV
White noise refers to any sound (it can be static or forest sounds) that “contains all frequencies across the spectrum of audible sound in equal measure”. Some people like white noise because it can minimise the disturbance caused by unexpected noises for them.
But does white noise really work? “Our current understanding of the impact of white noise, nature sounds and similar auditory stimuli on the brain is incomplete,” said Dr Chow.
“Research suggests that white noise is likely to have little general effect on cognitive functions in neurotypical individuals, while nature sounds are associated with reduced stress levels and improved cognitive performance at certain tasks.”
The background noise provided by the TV can be relaxing or sleep-inducing, said Dr Vikas Jain, a clinical assistant professor of sleep medicine at the Stanford University School of Medicine, especially when it’s your favourite movie or TV show that may reduce the anxiety keeping you awake at night, he said.
If you’re working from home, background TV can “serve multiple purposes”, according to Dr Lim. “They can distract you from unpleasant thoughts, provide a comforting auditory presence, and enhance learning through auditory cues.
“These effects are grounded in how the brain processes sensory input and regulates emotions,” he added. “The brain’s limbic system, which governs emotions, can be influenced by auditory stimuli; pleasant sounds can help regulate mood by reducing cortisol levels and increasing serotonin.”
On the flip side, there is also research that suggests having the TV on while you work may not be a good idea. In a study on 90 college students tasked to read the newspaper, those who did so with the TV on in the background recalled less than the ones who read in silence.
The moral of the story? You do what works for you.
WHAT WORKS BEST FOR WORK, LEARNING AND SLEEP THEN?
On the whole, sounds that provide a good soundscape for work and sleep are “typically consistent, low in volume, and free from sudden changes, like soft instrumental music”, said Dr Lim.
“Elements such as language, beats per minute, volume and recording quality can all influence the brain’s response. Lo-fi music, for example, often includes ambient sounds like raindrops or soft taps, which can create a comforting and familiar auditory environment conducive to both work and relaxation.”
Sounds that have “low variability in tone and articulation”, and can be played on loop or are predictable are “generally the least arousing and perhaps more appropriate as background music”, said Dr Chow.
If you’re reading or writing, it might be best to avoid music with lyrics, said Dr Chow. “Listening to music with lyrics activates the parts of the brain that deals with auditory information. If we’re attempting to concentrate on a task that involves words, it can be taxing for our brains to do both flawlessly.” For that matter, you might not be able to concentrate on reading a report if you have a K-drama on TV.
For sleep and relaxation, Dr Chow suggested slower music based on what studies have found. “Slower music synchronises with our parasympathetic nervous system through a process called entrainment, where the body aligns with the environment’s rhythm.
“Essentially, the brain recognises that it does not need to be in fight-or-flight mode because the sounds remain consistent. Focusing on these sounds helps distract us from anxious thoughts or other noises that might keep us awake. These sounds help decrease stress by regulating stress hormones like cortisol,” she said.
