It has become common knowledge that some things—food, porn, outrage-share inducing articles—exploit a mismatch between our evolutionary heritage and the modern world, and do so at our expense. It seems, however, that we’ve collectively neglected one particular contemporary, omnipresent superstimulus: sound.
For a large proportion of my waking hours (70%?), sound is being directed straight into my eardrums. Not loud sound; I’m not worried about the health of my ears. Not “bad” sound; most of it is classical or electronic music, or ‘serious’ nonfiction audiobooks and podcasts. Yes, there’s a dash of delicious culture war content sprinkled among the podcasts and a healthy splash of music that might offend perhaps a 1980s Sunday school teacher, but I’m definitely not worried about the content.
What is starting to concern me, though, is the sheer lack of silence I experience in my daily life. Nothing specific is making me concerned, but it is gradually dawning on me that doing or consuming an excess of anything that was scarce in our ancestral environment, even the most benign music or informative nonfiction, can have a adverse effect on our mental and physical wellbeing.
While I am by no means the first to take notice, it isn’t like there’s an overwhelming amount of high-quality research and reporting on this. When I Google “Is silence important?” (the first phrase that came to mind, so not cherry-picking) plenty of listicles and a few other pop science articles come up: “7 Benefits of Silence,” “An Ode to Silence,” “10 Reasons Why Silence is Really Golden,” and “The Hidden Benefits of Silence,” to name a few. But the vast majority are some combination of poor quality and not actually about silence.
The first link, Google’s “featured snippet,” is a blog post by a soundproof enclosure company.
The second, Google’s first actual result, isn’t even about silence - it’s (mostly) about generalized hyperstimulation, stress reduction, and relaxation. Take, this paragraph, for instance:
“When we’re frazzled, our fight-or-flight response is on overload causing a host of problems,” says Dr. Sullivan. “We can use calm, quiet moments to tap into a different part of the nervous system that helps shut down our bodies’ physical response to stress.”
A lot of links cite the 2013 study Is silence golden? Effects of auditory stimuli and their absence on adult hippocampal neurogenesis, touting the finding that silence could stimulate neurogenesis but conveniently forget to mention that:
2. There’s a pretty good chance that adult human brains can’t even produce new neurons!
Not only do precious few rodent studies have anything meaningful to say about humans (see Are animal models predictive for humans?), but touting this study is akin to touting the finding that vitamin A consumption improves whisker quality. As just one example, this bullet appears in one article’s list of the health benefits of silence:
Benefit brain chemistry by growing new cells. A 2013 study found that two hours of silence could create new cells in the hippocampus region, a brain area linked to learning, remembering, and emotions.
At least they linked to it.
That said, there are a few diamonds (eh, maybe quartzite) in the rough. Lifehack’s “Science Says Silence Is Much More Important To Our Brains Than We Think” at least refers to “a 2013 study on mice,” and ties together a few interesting lines of reasoning as to why silence itself might be beneficial, above and beyond mere relaxation.
A study [link added by me] published in the journal Heart discovered that two minutes of silence can prove to be even more relaxing than listening to “relaxing” music. They based these findings of changes they noticed in blood pressure and blood circulation in the brain.
Will it replicate? Who knows, but I’d bet on it. If you’d like to try for yourself, they used Beethoven’s Adagio molto e cantabile as the “soft classical” song. If this is true, the finding that silence produces a physiological effect distinct from relaxation is important and non-obvious.
While not really backing up the claim, the article also argues that
When you are not distracted by noise or goal-orientated tasks, there appears to be a quiet time that allows your conscious workspace to process things. During these periods of silence, your brain has the freedom it needs to discover its place in your internal and external world.
which intuitively seems correct.
This article in Nautilus features the unexpected and frankly fascinating findings that
While it’s clear that external silence can have tangible benefits, scientists are discovering that under the hoods of our skulls “there isn’t really such a thing as silence,” says Robert Zatorre, an expert on the neurology of sound. “In the absence of sound, the brain often tends to produce internal representations of sound.”
although intense cognition caused spikes in some parts of the brain, as you’d expect, it was also causing declines in the activity of other parts of the brain. There seemed to be a type of background brain activity that was most visible, paradoxically, when the test subject was in a quiet room, doing absolutely nothing.
I think I know why so many different articles all cite that 2013 mouse study: there isn’t a whole lot more to cite. When I try to find research on Google Scholar, using keyword combinations like “silence,” “quiet brain health,” “silence neuroscience” and the like, the vast majority of results are using “silence,” or “quiet” as a metaphorical descriptor:
Of these results, only the fourth is actually about an absence of sound. Even among the 60 papers that cite that 2013 study, I can find only two that actually compare the cognitive or physiological effects of silence and sound (first, second), and the latter is basically just a commentary on the virtues of introversion.
So, after maybe 45 minutes of digging around, I found three scientific studies on the subject matter, finding respectively that:
I’m 110% sure that I’m missing most of the research out there (like those cited in the third bullet that I hadn’t seen), but I’m also 99.9% sure that there is way less research on silence than things like fasting, meditation, porn consumption (links to Google Scholar search results), and other contemporary superstimuli and efforts at their correction.
To be fair, there is quite a bit of research on loud sound, both in the context of ear health/hearing loss and of stress or other psychological effects, but virtually none of this seems applicable to the difference between silence/mild ambient noise, and normal, “intentional” sound like music or television.
So far, I’ve leaned on my credentials as an armchair anthropologist, neuroscientist, and evolutionary biologist to assert that premodern people must have been exposed to silence more frequently than us. After thinking for about thirty seconds, there’s no way this is literally true. Birds chirp, leaves rustle. I can’t even comprehend how the typical caveman would have found near-total silence except by literally crawling deep inside a cave.
That said, it seems plausible to me that everything I’ve discussed so far isn’t really about silence, but about the absence of what I just referred to as “intentional” noise. Intuitively, it seems likely that there is a meaningful difference between hearing the sound of waves crashing, or rain, or wind blowing, and listening to soft classical music or a mellow conversation.
After all, music is designed to produce an emotional/aesthetic/psychological reaction, and speech is intended to transmit information. The birds outside don’t give a shit about how their chirps make us feel or what they make us think. So, there has to be something different going on in the brain between processing ambient, meaningless noise and something like speech or music.
While I am aware that natural sensory stimuli, including nature sounds, likely have a distinct, positive cognitive effect on us (in comparison to their absence), it is still very unclear to me how much of this benefit simply comes from giving our brains time away from “intentional” sound. For instance, what is the difference between hearing a gurgling creek and hearing a refrigerator quietly running in the background or cars occasionally pass outside? I have no idea.
Also, where is the border between “intentional” sound and whatever level and type of sound produces distinct cognitive benefits? Do we need complete silence? Seems unlikely, since our ancestors probably didn’t have access to it. Is a gurgling creek in fact “better” for the modern mind than the sound of a space heater? Maybe.
At what point does “music” turn into “ambient noise?” Is listening to the same soft piano song on repeat for hours more like hearing a new classical song, or more like leaves rustling in the wind? What about this hour-long, super mellow electronic piece that I put on for tasks requiring serious cognitive effort?
The notion that I might have a silence deficiency has been dawning on me over the course of maybe three or four months. One of the good things about writing things down, though (especially which I plan on making public), is crystalizes and clarifies what were vague notion in the back of my mind. When I made my list of book recommendations, simply writing “this recommendation applies to me, too” led me to actually read (well, listened to) the book in question.
Anyway, I’ve been making something of an intentional effort to listen to nothing as often as I can bear. The two most common occasions for this are driving and walking (I too have picked up this lockdown habit). Before, I would put on music, a podcast, or an audiobook virtually every single time I was in the car or on a walk. I still do, sometimes, but at least, eh, maybe 30% of the time I give my ears a rest.
Yes, I know this is pretty pathetic. I average 45 to 60 minutes of driving+walking a day, so this works out to something like 15 minutes a day, 1.75 hours a week, or 1.5% of my waking hours without any “intentional noise.” To my credit, this isn’t all the time I’m not listening to anything. I take my headphones off to do random stuff, eat, etc. But most of these things are consuming my general, non-auditory attention. Intuitively, it seems like silence should really “count” only when you would be able to listen intently to lyrical music or comprehend an audiobook, so walking and driving are in but, say, cooking a dish from a detailed recipe is out.
The sheer conscious experience (aka phenomenology, for us philosophy nerds) of silence is interesting, at least in comparison to the alternative.
Let’s say I’m on the 20 minute drive from my house to Earth Treks, my climbing gym. I’ve done the same drive down 495 probably at least a hundred times, so I’m on total autopilot. You should take the following report with a grain of salt, since introspecting and accurately reporting on one’s own conscious experience is likely difficult and plausibly impossible (check out illusionism), but I’ll try my best.
If I’m listening to something, it is generally a song I’ve heard quite a few times before, so I’m anticipating the coming melody and lyrics. Sometimes, my experience is “inside” the song, in that a good amount of my attention is directed to the notes and lyrics themselves. Other times, I will lose focus on the song and let my default mode network take the reins, my thoughts jumping without intentional direction between memories, concerns, plans, and other random bits of thought.
Now, let’s suppose I’m driving in silence. Not total silence, of course; the sound of the car itself is omnipresent. Nonetheless, it does not seem to be an object of my attention any more than a fan blowing in the background might be. Without a distraction or object of attention, my mind wanders in a similar fashion, but with more earnestness or intentionality, for lack of a better descriptor. Instead of flitting back and forth between the song and different, arbitrary thoughts, the thoughts tend to linger for longer and receive more attention
Often, some thought—a memory, a problem I’m trying to solve, something I have to do, whatever—doesn’t merely occur to me, but actively elicits “my” (what I perceive as my intentional, conscious mind or ego) participation. This can take the form of simple directed attention at the thought or a more active attempt to “manipulate” the thought in some way - perhaps by actively trying to solve some problem or making some sort of plan.
More interesting, and most peculiar to times of silence, is when some subconscious neural activity bubbles to the surface in the form of a sudden “insight” of some kind. This could come in response to some explicit intellectual project such as a research paper, but it is often much more mundane.
Two days ago, after beginning to write this post, I went on a walk around my neighborhood sans headphones. The week prior, my (fully vaccinated) parents had gone on vacation, leaving my mostly-introverted self some delightful peace and quiet. Don’t get me wrong - my parents are fantastic and quite respectful, but there is a distinct cognitive load for us introverts associated with the omnipresence of other people, which for me makes it much harder to get into a Cal Newport-approved state of “deep work”-esque focus.
Anyway, walking around the neighborhood, it suddenly became clear that I should make the small amount of effort required to move my desk, chair, notebooks, and other materials to some more secluded part of my house. Not exactly a world-shattering insight, and one I certainly had all the information to come to without the need for deep introspection. Nonetheless, it seems overwhelmingly likely that the unprompted, sudden intuitive desire to do so was a direct result of giving my brain a few minutes without anything to do.
And so I am currently writing these words on a different floor from all other human beings, in my sister’s old bedroom-turned-makeshift-office (thanks Lindsay). Instead of getting up for the 12th time to turn off a light that someone just turned on or to close the door that someone just opened (both before leaving the room), I am staring out a window at the brownish-red leaves of the tree outside. All likely because I decided to forego listening to Travis Scott or (RIP) Juice WRLD (which if I recall correctly were my top artists of 2020 on Spotify) for the 1700th time.
In addition to staring at those rustling leaves, I am also writing these words while listening to Spotify’s Lo-Fi Beats playlist, my usual writing/working music alongside their Instrumental Study playlist. Am I losing something important by doing this? Would this post have been better written or more insightful if it had been written in silence?
I have no idea. Despite everything I’ve written so far, I am by no means convinced that soft classical and electronic music are going to be remembered as the corn syrup or canola oil of our ears. I’ll reiterate my list of questions a few paragraphs up:
Where is the border between “intentional” sound and whatever level and type of sound produces distinct cognitive benefits? What is the difference between hearing a gurgling creek and hearing a refrigerator quietly running in the background or cars occasionally pass outside?
Would going on my walk with Mozart instead of Mac Miller (also RIP) have led to the same insight as did going in silence? I can’t rerun the experiment, and I’d honestly put the odds around 1:1.
As a final bit of quarter-baked speculation, what’s the relationship between meditation—which has deservingly found its way into certain subcultures of the West—and mere absence of stimulation, auditory and otherwise? Is meditation to quiet what HIIT (high intensity interval training) is to less strenuous movement, or what 5,000 iu vitamin D supplements are to sunlight—that is, a concentrated megadose of something that used to be abundant?
These questions aren’t rhetorical, and I really would like to know the answers. For now, though, I’ll try to choose silence as much as I can. The music can wait.
I've spent most of my life in areas with low noise pollution. The best way I can describe the experience is that relevant ambient sounds build an understanding of my surroundings like the mini-map in the corner of a video game, which shows all the important events going on within a few hundred yards of the player's character.
In areas with low noise pollution, that mini-map is beneficial: it takes little to no conscious thought to keep it up to date, and it offers me information that I care about, such as where the people and animals around me are and what they're doing. The wind makes different sounds when it blows different directions; rain's various rhythms and drips tell me as much about it as I'd know if I watched it visually; bird songs reveal that the birds think it's business as usual outside and their absence says that something out there has impressed the birds as being even more interesting than yelling at each other. In an area with few vehicles, it doesn't take special effort to listen to each one: It's easy to tell whether it's light or heavy, gas or diesel, fast or slow, coming or going, traversing the paved road or a gravel driveway. Different people walk in different ways and make different little noises, which the brain starts picking out by itself when given enough good data to pattern match on.
When I visit areas with higher noise pollution, that mini-map gets cluttered with dozens or hundreds of overlapping facts about the environment, to a point where it's worse than useless and I try to turn it off by overriding it with distracting sounds like music or podcasts. When asking friends who were accustomed the noise why it didn't bother them, it became clear that some people who spend most of their time in areas with high noise pollution don't seem to experience that mini-map, or quarter-mile of personal space, that I take for granted when it's available.
This is the best explanation I've ever seen for this phenomenon. I have always had a hard time explaining what it is like to people, so thanks!
Not surprisingly, blind people also rely on similar sound maps, and are very aware of the acoustics of different surroundings. IIRC some blind people can echo-locate like a bat by making tutting/clicking sounds with their mouths, and listening to the reflection, enabling them to tell when they’re near large objects!
Good post. This could be an important topic. Some thoughts arising:
Maybe research on noise pollution (eg from traffic, aircraft, wind farms) would say something about it.
Also maybe research on noise distraction as people get older. I'm 52 and have noticed in recent years I find background noise, particularly loud music in cafes, increasingly annoying and distracting. I assume this is because the brain has to work hard to blank it out (cf the so-called 'cocktail party effect'); hence that even in younger people it's using up brainpower somehow. I've never been able to do intellectual work with background music, and am baffled by people e.g. programmers who work with headphones playing music all day. But maybe for them it does just use different parts of the brain.
When I have a shower in the morning I listen to the radio news, but realise this is just ear-candy because there's rarely much of great interest. So sometimes I switch it off and then often have a flood of useful ideas - I assume partly because of the well-known phenomenon of thinking in the shower (I assume related to thinking on walks - see separate comment), and partly because I've been asleep so my brain is relaxed, able to freely associate, and also maybe has been half-thinking about various topics while I was asleep. Which confirms my suspicion that background sound - particularly attention-grabbing sound such as speech and music - inhibits thinking. But nonetheless I do find it quite hard to switch the radio off - I crave the ear-candy.
Relatedly, research on boredom might be useful. There's the interesting experiment where people are put in an empty room to sit in silence for a few minutes, with the option to give themselves electric shocks. Many (particularly men) choose to to avoid boredom. Presumably cavemen wouldn't have done this. I assume this shows that we are generally overstimulated in the modern world, including by sound. Many observe that smartphones etc. provide too much stimulation, and that in our parents' and grandparents' day people were much more able to do nothing, or at least create their own entertainment (an active process, rather than passively listening).
Thanks for your perspective.
I've never been able to do intellectual work with background music, and am baffled by people e.g. programmers who work with headphones playing music all day. But maybe for them it does just use different parts of the brain
For me, there is a huge qualitative difference between lyrical music or even "interesting" classical and electronic music, and very "boring," quiet lyric-less music. Can't focus at all listening to lyrics, but soft ambient music feels intuitively helpful (though this could be illusory). This is especially the case when its a playlist or song I've heard a hundred times before, so the tune is completely unsurprising.
Yes I’ve heard others say they can’t listen to lyrics.
The one thing I’ve started playing recently in the otherwise silent room where I work is quiet birdsong (background level, hardly noticeable). On the grounds it may have a subconscious effect of making me feel I’m outdoors, which may be conducive to creativity (cf walks), or at least be relaxing.
The birds outside don’t give a shit about how their chirps make us feel or what they make us think.
I strongly agree that birds are assholes.
Seriously though, I will delve into this tomorrow more, as it is relevant to my interests.
Regarding the walking anecdote, a bit of devil's advocate: Walking, by itself, has been shown to improve problem solving, and creative thinking in particular. "In one of those experiments, participants were tested indoors – first while sitting, then while walking on a treadmill. The creative output increased by an average of 60 percent when the person was walking, according to the study."
Interesting, thanks. Assuming this effect is real, I wonder how much is due to the physical movement of walking rather than the low-level cognitive engagement associated with doing something mildly goal-oriented (i.e. trying to reach a destination), or something else.
I also read a paper that compared walking in nature with walking in a city, I think with regard to creative thinking. Walking in nature did better. It speculated that that's because a city has more distractions, such as big buildings and sources of danger (traffic etc.) Also that the creativity produced by walking is because the slowly shifting surroundings gently prod your unconscious for associations; whereas in a neutral fixed environment (an empty room) your thoughts can get stuck. That said that experiment above suggests there's something about walking itself that may (at least partly) explain it.
About the difference of "cars passing" and "birds chirping", I think there are two axes to it: translatability and variability.
I expect translatability from children (lots, even as background sound), cars (less) and birds (some, depending on the bird). It's something about ease of sorting the auditory information.
(And in the context of a mini-map nim described, it would be cool to map out the physical limits of the heard area.)
But noise variability is another matter. When we talk about silence, what matters more - the intensity of sound or it's spectral parameters? There's at least one classification of noise (for example, https://en.m.wikipedia.org/wiki/Colors_of_noise ). I can't hear the difference between, say, white and pink noise, and I'm like 90% sure they have indistinguishable effects on health and cognition, within "not loud doses"). But at least it's some quantitative way to describe it.
Thanks for writing this. I do think it's an interesting question to explore.
I'm not sure what to make of it though. When I was in college, and even at work, I found I could actually concentrate better with some background music or noise going on. Not just any sounds but something you might say was "known" or "familiar" or "expected". Too quiet an environment was oddly a distraction for me.
That still holds for me but I do often find myself in a quiet setting. What I notice is that the quieter my environment is the louder my thoughts are -- I hear my thinking rather than just think and do.
I'm not sure what I should make of that observation though.
I suspect, based on what happens when people start meditating, that your mind was flinching away from a lack of distraction that normally keeps the parts that are suffering occupied. I'm pretty sure this is why most people find it easier to concentrate while listening to music: they need to distract themselves enough from moment to moment suffering to get enough mental slack to get anything done.
A somewhat disturbing implication. But worth considering just what I am still doing some repression/avoidance about. Thanks for the comment.
Thanks for writing this up! I've listened to a TTS version of it 😅.
I'm spending most of my "in between activities" time (walking, biking, eating, showering) listening to audiobooks/podcasts and to a lesser degree - music.
And for a long while I've been wondering about things similar to what you mention in the post:
I don't really have any conclusions/insights on this so far 🙁, but I'm excited to see people starting to explore the topic, and I'd be curious to hear your longer-term reflections on your self-experiments with silence!
https://www.lesswrong.com/posts/i42Dfoh4HtsCAfXxL/babble seems tangentially related
Simply put, I think this is a pretty concrete example of neglected areas of research that skew our rational understanding of the world, and calls into question the reasons why this blind spot exists. Studying the reason for this blind spot is important as it relates to legislation, academic priorities and the politics underlying the domain.
On a related topic, the implications for AI/ML analysis of this area of research, especially as it pertains to other areas of research which would rely on statistics generated from 'all the available research' could potentially be disastrous, especially if all of these types of blind spots in aggregate are taken into account.
If there simply isn't research to analyze, and/or the research is so one sided ( as in this case there is plenty of research about excess of noise and the like, but little on Silence) than any conclusions AI might come to would be potentially dubious depending on how the analytical setup was implemented.
Simply having a human and or humans actually do the research to help flesh out the overall datasets AI and human researchers could consider would be far more useful in the long run, than just leaving things as they are and attempting to create something like a world model with infinite compute power to virtualize the entire universe and model the human brain so that the entirety of scientific endeavor could be done in a virtual world, apart from the world and humans that would ultimately be affected by it. For various reasons, depending on the output of this hypothetical AI, we probably wouldn't understand it's reasoning, or even be able to decide if it was correct or not. What use would that be?
Plus promoting human research into these blind spots would make more money available to more humans to do more research now, thereby offsetting some of the losses in the labor force that things like automation and robotics and AI and ML have caused. It would also cement into the actual neural wiring of humans, the ideas and concepts they were researching, so that they could still engage with the science and meaning making in a meaningful way.
The iterative capabilities of computers have sort of negated the need for human thinking and development in many areas, as people and their limited abilities are neglected for development that matters to them - significantly modifying their brain structure to create unique human capabilities and identities - instead of just meaning something to them - by simply adding one more abstract concept to their brain structures which recruits less of the wiring regarding the matter of the meaning.
Allowing humans the dignity to do some of the intellectual work still, is a concern I have for the future. The more we rely on AI to point out our flaws and compensate for them, the less we develop these abilities ourselves, and the less AI will depend on humans in the future at the same time making us more dependent on them. That's a dangerous proposition.