1. Hydrotherapy
Whether it’s a babbling brook, waves breaking onshore, the steady rush of a waterfall, or the drumming of a rain shower, the sound of water is unprecedented in its ability to calm our jangled nerves and lull us to sleep — just ask the droves of music producers who earn their livelihood by recording aquatic melodies and selling them to insomniacs and stressed-out individuals. The secret to water sounds — relaxing effects may lie in the primal rhythms they contain, which help people regulate their breathing, quiet their minds, and call forth memories of blissful time they’ve spent in nature.
2. Snap, Crackle, Pop
Certain repetitive sounds have the opposite effect water does: each sonic burst is a mini-pick-me-up. These noises include dry autumn leaves, hard-packed snow, or loose gravel crunching underfoot, as well as bacon grease popping in a frying pan. Like a rushing river, such sounds have a rhythm all their own, but it’s more staccato and therefore more invigorating. In addition, the sound of a car rolling up a gravel driveway can fill listeners with excitement as they anticipate the arrival of a long-awaited guest.
3. Light My Fire
Whether it’s outside at a campground or inside in a fireplace, the crackling of a fire is mesmerizing to most people; it hypnotizes them into a drowsy, quiet state, punctuated by an occasional mm-hmm. These hearthside sounds may resonate because of humans’ age-old fascination with fire, one of the first tools they used to consciously manipulate their natural environment to keep themselves warm, cook their food, and even herd animals.
Nocturnal gatherings around fires at night were also some of the earliest social gatherings, spurring communication and fostering relationships. Many millennia later, the sound of a fire may trigger some primitive memory of this turning point in human evolution.
4. Laugh-In
If laughter is indeed the best medicine, then an infant’s delighted squeals as she discovers her own toes or a toddler’s raucous giggles when he’s being tickled are the ultimate panacea. The pure, unself-conscious joy that children’s laughter projects is contagious; it liberates adults from their day-to-day stresses by reminding them of more innocent and carefree times. And for the parents of youngsters, their kids’ belly laughs can be a reassuring sign that all is well psychologically and that the parents are making sound child-rearing decisions.
5. Noise Pollution
Ironically, one of the most widely used therapeutic sounds is not a single tone at all, but rather a combination of all sonic frequencies playing simultaneously: white noise. So named for its similarity to white light–which is not an absence of color, but a mixture of all colors–white noise works by absorbing all background noise and “reprogramming” it as a steadier, more calming buzz, not unlike the sound of radio static. As a result, it’s an effective sleep aid, a treatment for tinnitus, and a concentration booster (to block out the distracting sounds of noisy coworkers, for example).
6. And the Winner Is…
In 1935, two Bell Labs researchers named Harvey Fletcher and W.A. Munson conducted an investigation into human hearing that remains the most renowned study of its kind to this day. In measuring the frequencies that the ear is most responsive to, Fletcher and Munson discovered that people’s favorite sound of all is that of the human voice, which falls right within the ideal range of frequencies (300-3,000 Hertz) for our hearing. The only question is, did our voices evolve to suit our ears, or was it the other way around?
