I had a curious experience after I started walking daily in the city with crowds of commuters while wearing isolating earphones. In short, the space that I normally give other people around me diminished - without me even realising it.
It got me thinking about what an extraordinary human sense our hearing is, and how much we can take it for granted.
First, a bit of backstory.
Last year I changed jobs. That also meant a change to my work travelling routine of the previous 7 years. From infrequently walking in peak hour crowds, I was now jostling with commuters in the city every morning and evening, five days a week.
Being a music junkie - coupled with my deep loathing of loudmouths on mobile phones - I usually commute while wearing my favourite earphones: Etymotic HF5's. You moisten the rubbers tips and in they go, giving you about 70 to 80% isolation from outside noises so you can enjoy sweet, sweet music in all its glorious high fidelity. Best of all, you can listen to music at low volume without other noises drowning it out.
What I noticed was this: while wearing these earphones as I navigated crowds on the pavement and in tunnels, my sense of personal space changed. I found that I was walking with, or passing, or weaving among other people at unusually close range - and without caring. Assuming at least some of those people had the same sense of personal space that I normally have, I wondered how that made them feel. I can probably guess: jackass.
I’ve now checked myself and stopped the behaviour. But the realisation that I was even doing it came slowly.
So what’s going on here?
We all know the visceral dangers of wearing earphones and not being able to respond to obvious noise cues in the environment - horns, shouts, car motors and so on. But this is far more subtle. And I don’t usually play music loud when I walk, so I doubt the simple explanation that I’m just being distracted by the music and not paying attention to my surroundings.
You probably think, as I did, that sight and touch - and smell, to an extent - are the senses that determine our comfort zone in various circumstances that involve closeness to other humans.
But it seems to me our ears are also collecting information that can determine a comfort zone for proximity to other people, even if we aren’t consciously aware of it. That’s my theory, anyway.
Some expert opinion
After pondering this for some weeks, I decided to seek some answers from people who might know more about this sort of thing. Assorted Google searches turned up little, despite quite specific search strings. While I couldn’t find a neuroscientist at my local universities who I could get access to, I did put the question to Peter Miller.
Peter is an Australian musician, composer, producer and - especially - a sound designer of excellent repute. He’s designed the audio for Hollywood movies like The Ring (2002) and Rango (2011). He’s been in the game since the 1980’s and has a lucid understanding of sound and acoustics.
“I do think there is some psychological basis for what you’re observing though, but I suspect it’s quite complicated,” he says. “First of all, I would point out that the actual unnatural state is not the quietness and solitude of your personal listening space, but is in fact the noise and high population density of your commute. We’ve become so used to noisy environments that we tend to normalise them, but there is experimental evidence to suggest that noise keeps us in a higher alert state than is usual. This probably has some advantage in negotiating busy crowds and traffic. So by quieting down your listening environment, you are almost certainly dropping your alertness level.”
Okay then. So the stimulation of noise on a crowded street could make me more considerate of others around me due to my unnaturally increased alertness. That’s interesting.
But he also points to more explicitly neurological factors.
“It occurs to me also that disassociating one of your primary senses from the others is probably taxing on your brain in a fairly major way. Our auditory sense is not one that we pay a lot of attention to under normal circumstances - we are primarily very visual creatures. Nevertheless, our brains are continually extracting information from our environment, and that information contributes to our world picture. By disassociating aural information from the other senses, we’re almost certainly causing the brain to make strange assumptions. This would go some way to explaining what I call the ‘movie soundtrack effect’, where your world experience becomes somewhat stylised according to the music you’re listening to. I’m sure you’ve encountered that effect.”
“The other thing is that other people in a crowd are not experiencing the world in the way that you are, which can be problematic. When humans are in a crowd together - without headphones on - they react according to the sum of the environmental information they’re receiving. Sound plays a big part in that, and you’re mostly unaware of it.”
Peter gives the simple example of a subway, where everyone knows when a train is arriving because they hear it first. This psychologically prepares everyone for the process of boarding. It’s a small thing, but it goes to making the process of being a commuter more fluid.
“There are probably hundreds of small aural cues that occur during your commute that you’re not aware of. You can ‘get by’ on the visual cues, but it’s probably more taxing on your brain. I certainly see no problem with listening through headphones when you’re seated on your journey, for example, but there maybe reality conflicts when you’re moving, negotiating traffic and crossing roads.”
So there’s my answer, or an answer at least. It’s nuanced and complex. Just like our hearing, really; a sophisticated sense that is often forgotten in a world dominated by colour and movement.