The Universal Sense (24 page)

If being driven insane by the sound of your own heartbeat isn’t your thing, perhaps you’d prefer to hear a
lot
of sound. Under some circumstances we all like loud input—turning up your portable music player, blaring your stereo or TV, or going
to a movie where the explosions seem to constitute 50 percent of the soundtrack. But what underlies this drive for loudness? And how can it be used or misused? The answer is pretty simple and clearly defines high volume as a brain hack: loud noises activate your sympathetic nervous system. Your sympathetic nervous system is the control system for the three f’s that drive a lot of vertebrates’ lifestyles: fight, flight and fffff-igure it out.

Very loud sounds, especially ones with sudden onsets, are treated differently. First of all, loud noises activate your whole inner ear, not just the cochlea, the part that normally detects and codes sound. If a sound is loud enough, it will trigger non-cochlear parts of your inner ear such as the sacculus, an organ normally devoted to balance that picks up low-frequency vibrations and lets us know which way is up. If there is a sudden loud bang, even the most acoustically OCD person is not really concerned with its frequency content, its possible linguistic meaning, or whether it is consonant or dissonant. He is mostly relieved by the fact that whatever made the loud sound didn’t land on him. A loud, fast sound makes you respond with a highly stereotyped and very fast behavior (usually only involving three neurons): the sound activates the sacculus (normally a gravity sensor), which triggers high-speed motor pathways involved in posture control, making you hunch your head between your shoulders and jump a little. In short, you startle. But beyond the quick motor response, the loud noise also causes both auditory and vestibular signals to pass from your brain stem in the other direction, along a slightly slower route to regions that increase arousal and alertness, just in case the anvil that just landed next to you was merely the first of many.

Is a sudden startling sound a brain hack? Sure, if you use it
right. Take a movie with not much happening. All is quiet. The spaceship is cruising with all systems green or the family is happily having dinner. And then—
boom
. A well-done, well-placed sudden sound and you startle right out of your seat as the Thing pops out of someone’s chest onto the spaceship lunch table or the jet engine comes through the dining room ceiling, still attached to much of the jet. The audience’s heart is racing, seats are damp. I think that qualifies.

But you can argue that though a loud sound may startle you, it wears off easily. Startles are triggered only once or twice and then the person habituates to the signal. Yell “boo” at a baby a couple of times, and by the third time, the kid just looks at you like you’re crazy or cries or both and the diaper is full and the baby-scaring fun is gone. Or a scene in a movie where the monster keeps on roaring as it pops through everyone’s chest becomes a joke, not a terror-inducing moment. A noise-induced startle is a good means of showing how signals from your ears can trigger a short-term arousal response, but what about loud continuous or repetitive sounds?

At a physiological level, as mentioned earlier, loud is bad. Your ears and your brain respond to excessive volume, whether startling or chronic, by trying to get control over the signal or, failing that, trying to get control over your own behavior. If you aren’t making the loud noise, you try to figure out where it’s coming from and move away, plug your ears with your fingers, or just bang on the ceiling with your broom to get your neighbor to shut the hell up. So why do we sometimes immerse ourselves in loudness? For the same reason that some people BASE jump or ski or drive too fast—because activating the fight-or-flight system gives you a rush, a temporary surge of excitatory neurotransmitters such as epinephrine and dopamine
which light up the arousal parts of your brain like a neon-bedecked Christmas tree at a rave.

If the loudness is not under your control, you get a different set of behavioral effects as you try to bring your sympathetic nervous system under control (presuming, of course, you can’t just leave or turn down the volume). Your brain has a specific mechanism for dealing with sensations that are under your control—it’s called an efference copy. It’s the reason you can’t tickle yourself and why you usually won’t get carsick if you’re the one driving. It’s an automatic program that links your brain’s executive decision-making centers with your perceptual centers via a mechanism called
motor-induced suppression
. One of the more familiar times it gets called up is during speech production, because if you’re yelling to get a friend’s attention across a room, it’s going to be
really
loud inside your head.

To prevent deafening yourself, this reflexive system drops the gain (or relative loudness) and decreases your auditory sensitivity to your own sounds, but it can get activated even when you engage in something non-speech-based, such as reaching for the volume knob. Let’s say you’re listening to your favorite song and you decide it’s a good enough track that it really deserves to make the walls pulse and your chest resonate. Your brain makes a brief plan, not only of the motor functions it will have to carry out to reach over and turn the volume up but also of what it expects will happen (things will get louder). This feed-forward command sends information to your auditory system that things are about to get loud and actually reduces the sensitivity of your brain to incoming sound. You can tell it’s louder, but it will damp out the what-the-hell-was-that aspect of someone else making an unexpectedly loud noise in your area.

But what happens if you’re not the one in control of the
volume? How many times have you been watching a TV program or a video on the Internet and suddenly the ad comes on twice as loud as what you were watching? This is deliberate—it’s a way of getting your attention and increasing your arousal by activating your sympathetic nervous system. But while it may have been a clever trick long ago, when radio and broadcast TV still ruled the Earth, its overuse has created its own downfall: it spurred the rise of TiVo, which allows viewers to skip ads entirely; the recent signing into law of the Commercial Advertisement Loudness Mitigation (CALM) Act, which requires broadcasters make sure that ads are not louder than the programs in which they are presented; and the adoption of a mute button on every remote control device out there, returning control over your auditory world to you. This is, unfortunately, characteristic of the way media often try to use psychological “tricks” to increase consumer name recognition and attention. While the technique uses one basic perceptual principle—increasing attention and arousal through loudness—it ignores an even more powerful one, habituation. So instead of increasing your memory of a brand and forming associations between it and the desired sympathetic f’s, instead the noise ends up making you annoyed with the ad and hence with the product, and using the flight f option to avoid it.

But what about when the environment you choose to be in is inescapably loud? You’ve no doubt run into this scenario. You walk into a bar where the din is so loud you can’t even hold a conversation without yelling into someone’s ear. You go into a store in a mall, particularly those that cater to a younger crowd, and suddenly you’re bombarded with 90 dB music levels that would make an OSHA inspector reach for her earplugs even before writing up a citation. Or you move through the quiet
entrance lobby of a casino into the gaming room, where the noise from hundreds of machines, bells, alarms, and other come-on sounds combines with the blinking lights to create an environment where you can’t hear yourself think. And that’s the point. Thinking can lead to rational, measured choices,
⁵¹
and frankly, whether you’re in a bar, a pricey store, or a gambling casino, rational, thoughtful choices are not going to help such an establishment’s bottom line. The sound levels in these places are not the result of poor design or acoustic accident. The point of such overwhelming sound is to increase your arousal, to activate your sympathetic nervous system. But since you have elected to go into this environment and have no way to lower the sound level, you will do what almost any animal will do when faced with an inescapable stressor: find a way to control it. In one study, rats were exposed to the choice between an unpredictable electric shock and pressing a switch that triggers a predictable one; they learned to choose the latter even though it meant pressing a switch that hurt them. And multiple studies have demonstrated that buying things or gambling—“acquiring controllable resources,” if you prefer the literature’s terminology—is a common strategy for exerting control (real or imagined) over stressful situations.

But it’s not an automatic “buy stuff” button. If I, at the tender age of fifty-one, am in a mall and pass an Abercrombie and Fitch, where the corporate-set level for music (according to one news report) is at 90 dB, I’m going to walk away from the entrance, not even exposing my eardrums to construction-site-level come-on tunes. But younger people are accustomed to and often seek out louder noise and music levels (which is why
younger drivers eagerly buy car mods that reduce muffler effectiveness to make cars louder). So this strategy is targeted to a specific demographic, the younger, more acoustically arousable purchaser. Similarly, in a casino, studies examining the effects of noise on gambling showed an interesting demographic effect. Casual gamblers showed an increased tendency to gamble more when exposed to loud noises, whereas those who were identified as having a serious gambling problem tended to bet less. One hypothesis to explain the difference is that while both groups are being subjected to increased arousal from the loud noise, the casual gamblers associate arousal with winning and bet more, while the problem gamblers associate it with losing and bet less. These two examples point out a very important point about sound-induced arousal: it varies based on who is listening, and thus affects the likely outcome of acting on the arousal. The targeted use of loudness, from louder ads to deafening store music, is an important but often misused marketing and sales tool.

Turning the volume way down or way up is the simplest form of brain hack, but how useful is it? You’re not likely to have an anechoic room handy at all hours and even the best noise-cancelling headphones drop ambient sound by only 45 dB or so (earplugs are even worse, at about 25 dB). And while too many of us, especially kids, turn up the volume too high or get stuck in noisy bars or casinos, we can and do ultimately escape—if not by leaving, then by the inevitable loss of hearing a few years down the line.

So how can you induce a global brain hack without access to a specialized facility or risking deafness? By realizing that volume is only a small part of the auditory world.

Another critical part is time. By manipulating the timing of
sounds, you can force large chunks of your brain that normally do their own thing into artificial synchrony.

The brain is used to dealing with a large number of simultaneous and asynchronous inputs—it’s a noisy world out there, even though it’s the one you evolved and developed to deal with. If you can eliminate the noise and overload your brain with one type of input, this sensory focus will do some very different things to your mind. This is the basis for a lot of mental states that go by a variety of names—alpha state, meditation, trance induction—but all it boils down to Global Brain Hacking Strategy Number 3: limit the distractions to intensify your focus. This is probably the type of brain hacking that you’ve probably heard the most about, because it is the basis of hypnosis and meditation.

Hypnosis and meditation seem like they spring from opposite types of input: hypnosis is usually brought about by surrendering your executive functions, your decision-making ability and attention, to another, while meditation is usually self-induced, by blocking environmental distracters from your attention and using some unifying stimulus from inside or out to help you achieve a more narrow state of focus than you usually aspire to before coffee. But despite the divergent approaches, both change your attentional state by limiting the amount of your brain you devote to processing the sounds of someone else’s cell phone conversation or that dripping faucet and free up those areas for other things, such as shifting or increasing attention, something very important for brain hacks.

What kind of stimuli can induce a person to stop paying attention to anything but a single focused input? Words spoken in a calm, rhythmic voice can act as an important focusing element, but often hypnotists will use a regularly flashing light or
the rhythmic ticking sound of a metronome to help the induction of a trance state. Why? Because attention is about shifting neural resources onto an object of interest, and the more attention you pay to an object, the more you pull neural resources from distracters. By choosing to pay attention to a specific sensory input provided at the correct rate, you start swamping local variations in parts of your brain that would normally slide off to wonder if you turned off the lights before leaving or what you’re going to have for dinner or even why the guy speaking to you so calmly would want you to squawk like a chicken. You are narrowing your sensory world to focus on overwhelming and synchronized sensory input. And as your normal waking brain is strongly dependent on differences in both the quality and timing of input, overwhelming it with a narrowly focused signal, ticking away while only a single voice speaks quietly and soothingly at the right rhythms in your ear to maintain this odd mental state, is why you see nothing wrong with squawking like a chicken after all.

But what are the “right rhythms”? Your brain has intrinsic rhythms, ranging from neurohormonal changes over periods of months to a single neuron changing its activity state in milliseconds or less. The most commonly referred to rhythms are the ones that involve large swaths of your brain hemispheres and are the ones usually reported by electroencephalography. While electrophysiological recordings of living brains actually go back as far as the 1840s, it was in 1920 that Hans Berger developed the EEG recording device, which was capable of non-invasively recording electrical signals from living brains. Modern EEGs are quite spatially selective, able to record from dozens or even hundreds of individual electrodes placed on the head, and are capable of extracting information about the timing of
neural signals down to the millisecond level. However, they all suffer from the same limitation—they are recording very weak signals (thousandths of a volt or less) through a very good insulator (the brain’s protective membranes and your skull, scalp, and hair). This means that the only signal that makes it through is a really a summation of thousands to millions of individual neuronal signals. You can’t analyze the response of a single neuron or even a local circuit, but with proper electrode placement, you can measure the responses of populations of cells that act in concert, and hence get a global view of how big volumes of the brain (on the order of millimeters or centimeters) respond to specific stimuli such as flashing lights or sounds, known as “evoked potentials.”