The Unheard Problem with Noise

Life in the city can be noisy. That’s not where I live, so I find my occasionally unavoidable forays into its bowels almost unbearable.

“How can you live like this?” I asked a friend as we sat on the patio of a coffee shop on a downtown street as an ambulance screamed by.

“What do you mean?” she answered, looking at me with puzzled eyes, her coffee on it’s way to her mouth undisturbed.

The noise had been so obviously intrusive and irritating, that words failed me for a moment. I raised my arm and pointed along the busy, cacophonous street.

“All the people, you mean?” She smiled innocently and shrugged. “It’s near lunch time, I guess,” she said, and picked up her coffee for another sip.

I rested my hands on the table to steady them before I made an attempt to lift my own cup. “Don’t you find it rather…” I paused as I searched for the proper word to describe my angst. “… turbulent?” It was probably not the best description, but I still felt agitated.

The smile wavered for a moment as she tried to decipher my question. Then she sighed –or at least seemed to sigh –I couldn’t hear her soft intake of air in the din that vibrated and careened around us as if we were sitting in the middle of a traffic jam at rush hour. “You’ve been away too long, my friend,” she said, shaking her head sadly.

I attempted to return her smile, but I think my lips were quivering too much for it to become the answer she expected. “Doesn’t all the noise bother you Janet?”

She blinked her eyes slowly in reply. It might have been seductive in another setting, but here it only seemed like a rebuke. “You learn to block it out. It’s an urban adaptation…” Her face softened at my obvious discomfort. “To tell you the truth, I don’t think I even hear it anymore unless it’s so loud it scares me…”

That seemed counterproductive to me, but I didn’t say so at the time. Warning signals are surely just that: alarms that are meant to alert those in the vicinity to potential risks. They’re supposed to provoke a reaction. In my case it probably heightened my awareness of the risks of signal fatigue. Of crying wolf too often. Perhaps it also sensitized me to research that recognized this and attempted novel technological solutions: http://www.bbc.com/future/story/20170714-the-brain-hacking-sound-thats-impossible-to-ignore

The alerting signal the article discussed ‘was inspired by neuroscience research on sounds that affect the emotion-processing centres of the brain.’ It was originally used in Malawi, Africa, ‘To alert Malawi locals to HIV tests and health checks from a mobile clinic […].’

The problem there, as here, was the brain’s tendency to adapt to frequently discordant and unpleasant ambient noise –blocking it from conscious awareness, in effect. It ‘was inspired by the neuroscience research of Luc Arnal at the University of Geneva. Arnal had investigated what neural connections are activated when humans hear a sound that is particularly difficult to ignore: screaming. Scans revealed that, when we hear the characteristically rough, distressing sound of a scream, the amygdala – which processes fear reactions – is activated in our brains. “What I found is that this roughness doesn’t go through the same neural pathways used by speech,” he says.

It means that screams don’t just get our attention, they immediately prompt us to react in some way. We’re stimulated to actually do something. […] Arnal had previously suggested that this insight could be used to design better alarms and sirens that don’t just make us freeze when we hear them, but actually invoke a more constructive reaction.’

An American artist, Jake Harper, had previously recorded  the music of a local band in Malawi and edited it into a form that ‘sounds like nothing you’d recognise from a street elsewhere in the world. Strangely unlike a conventional emergency services siren, instead it is a discordant mashup of musical fragments and intermittent white noise.’

‘Harper spent months experimenting with audio software to try and come up with a noise that sounded man-made enough to distinguish it from human or animal voices in the bush, but which was also not overly harsh or distressing. Getting the balance right – appealing to the emotion-processing parts of the brain without inducing fear or shock – was tough. The results were encouraging. Harper says that on average, a mobile clinic would test 40 people per day for HIV. “During the trial we had 160 people come to get tested,” he says.’

For Arnal, ‘that succeeds in meeting the three key goals here: produce a sound that grabs people’s attention; avoid distressing them; make sure it is distinguishable from non-manmade sounds in the environment.’

‘Our understanding of how audio influences human psychology has evolved greatly in recent years, according to Annett Schirmer at the Chinese University of Hong Kong. For example, studies have shown that people’s neural activity can be co-ordinated with the help of external rhythms. This is exactly the sort of effect you would expect from, say, factory or farm labourers working in time to a song – or the effect of cohesion observed in musicians performing together.

“Music stimulation entrains certain mental processes and aligns them between individuals […]” However, she warns there is also a dark side to using music to alter behaviour.

“Shops use music to make customers stay longer or increase the likelihood that they purchase things,” she notes.’

This is exciting stuff for sure. As Arnal observes, ‘In the future, sound that provokes responses deep in our brains could be more thoughtfully designed into the built environment.’ But we humans are an adaptive lot. We quickly learn to ignore sounds that might have been initially distressing when we first heard them. Apart from the morbid curiosity aroused by it, an ambulance wailing past soon loses its relevance if there is no one nearby who needs it. And if it becomes a too frequent and unwelcome guest, surely the doors to our ears would quickly become unwilling to allow it entrance. I’m not advocating for the Luddites, though, just for an appreciation of Darwin.

Or, perhaps, for the sentiment of Oliver Wendell Holmes as he observed in one of his poems: And silence, like a poultice, comes to heal the blows of sound.

The Body’s Clock

Scientists –well, all of us- have been suspicious about the health risks of shift work for a long time now. Perhaps there is a reason buried somewhere in our genes that suggests night is for sleeping and daytime for working. Originally, no doubt, it was because it was difficult to see things in the dark and lighting, even when it became available, wasn’t very good.

But there is another reason: the Circadian Rhythm (from the Latin circa –around, and dies –day) which is often defined as physical, mental and behavioral changes that follow a roughly 24-hour cycle, responding primarily to light and darkness in an organism’s environment. The body clock, in other words. And there’s the clue: light and darkness. These are not just elements in our environment that we have come to expect, they actually have a biological meaning for us although this is, to a certain extent, entrainable. Malleable. As Wikipedia (sorry!) puts it: The rhythm can be reset by exposure to external stimuli (such as light and heat), a process called entrainment. The external stimulus used to entrain a rhythm is called the Zeitgeber, or “time giver”. But it can take a while to adjust –think of jetlag, or sleep disturbance after starting a new shift at a different time.

The body can adapt to many things, no doubt; the problems seem to arise when the pattern keeps changing. As folk wisdom attests, we are inherently creatures of habit –acquired behaviour patterns that are repeated so frequently they can become almost involuntary. As no less an observer of folkways than Samuel Johnson once said: “The chains of habit are too weak to be felt until they are too strong to be broken.” So one might ask why we –and many other animals- seem prone to develop these routines, these almost unconscious ceremonies. Is it simply a need for predictability? Or is it something deeper, something tied to our evolutionary past..?

In our evolutionary development we obviously experienced disruption of light/dark cycles –they occur as we travel through the seasons- but these are gradual and steadily progressive; shift work –especially rotational shift work- is not. And only recently has it become more obvious that there may be a price to pay. There have been several studies that have looked at this in various ways, but ‘Although epidemiological studies in shift workers and flight attendants have associated chronic circadian rhythm disturbance (CRD) with increased breast cancer risk, causal evidence for this association is lacking’ as the abstract of a paper published in Current Biology noted. I saw this in a July 2015 article in BBC News reporting on a study co-authored by Dr. Kirsten Van Dycke which suggested that the chronic need to re-entrain the circadian rhythm because of changing light/dark cycles can increase the risk for both obesity and breast cancer! http://www.bbc.com/news/health-33569161 Now, admittedly, the study was done on mice who were prone to develop breast cancers anyway, but when the light/dark cycles were switched over a long period of time (‘Mice prone to developing breast cancer had their body clock delayed by 12 hours every week for a year’) they developed them sooner.

Humans are obviously not mice, but it is difficult to control for possible contributing factors in the average human study: ‘Several scenarios have been proposed to contribute to the shift work-cancer connection: (1) internal desynchronization, (2) light at night (resulting in melatonin suppression), (3) sleep disruption, (4) lifestyle disturbances, and (5) decreased vitamin D levels due to lack of sunlight. The confounders inherent in human field studies are less problematic in animal studies, which are therefore a good approach to assess the causal relation between circadian disturbance and cancer.’ http://www.cell.com/current-biology/abstract/S0960-9822(15)00677-6

And the conclusion from this study? ‘Animals exposed to the weekly LD [light/dark] inversions showed a decrease in tumor suppression. In addition, these animals showed an increase in body weight. Importantly, this study provides the first experimental proof that CRD [Circadian Rhythm Disturbance] increases breast cancer development. Finally, our data suggest internal desynchronization and sleep disturbance as mechanisms linking shift work with cancer development and obesity’.

This is worrisome, to say the least. One could certainly argue that a woman with an increased risk for breast cancer –say a heditarily aquired BRCA1/2 mutation- would be best to avoid jobs involving chronic irregular body clock disturbance such as flight attendants, commercial pilots, and so on. But I’m not sure the risk is confined to that population. What about others –especially if they have additional life-style risks such as smoking, diabetes, alcohol issues?

And what about men? If –as the study suggests- a chronic body clock disruption may cause a decrease in tumour suppression, would that not suggest a similarly increased risk? The disruption also seems to have an additional risk for increased weight gain –obesity. Is the risk for type 2 diabetes therefore also increased? Clearly this is an area requiring much more research -further elucidation of the mechanisms involved and mitigation strategies at the very least. Sleep is so important –regular sleeping patterns…

I can’t help but remember the words of Shakespeare’s Macbeth talking to his wife after he has killed Duncan, the king:

Methought I heard a voice cry, “Sleep no more!

Macbeth does murder sleep”—the innocent sleep,

Sleep that knits up the raveled sleave of care,

The death of each day’s life, sore labor’s bath,

Balm of hurt minds, great nature’s second course,

Chief nourisher in life’s feast.

Art, once again, anticipating Science…