On the Northern Beat The Science of Sound - November 2017
In a recurring theme I like to explore, I present you with some perhaps startling, hopefully informative and amazing nuggets of knowledge gleaned from the on-going scientific pursuit of knowledge in the field of sonics. Please use this information wisely. Scientists recently revealed this “new” information in the context of how effective rappers can be in creating rhymes, but WE know that bluegrass songs have always displayed this particular characteristic. Conveying meaning using rhyme is difficult, and sometimes, limiting to the point that “partial rhymes,” such as life and light, can be substituted effectively. “Different consonants at the end of a word often sound similar to people, and the new study suggests that [songwriters] capitalize on this fact to create pairs of words that seem to rhyme, even when they do not… The implication is that—not surprisingly—[songwriters] possess a subtle but deep understanding of how people perceive speech.” My exhibit A: Mike Finders! Now, let’s move on to “earworms.” No, not the horror movie biological type, but “snippets of music that pop uninvited into your head and won’t go away!” “Earworms are a generally benign form of rumination, the repetitive, intrusive thoughts associated with anxiety and depression [?]” Now, I usually enjoy the “snippets of music” that pop into my brain—but, apparently, this can be a debilitating annoyance for others who experience this as an unwanted obsession. “Most earworms are fragments, which very likely contributes to their stubborn longevity; incomplete memories last longer than complete ones, a phenomenon known as the Zeigarnik effect.” Strategies for getting rid of these earworms include chewing gum, silently reading, talking or singing to yourself (“which engages the tongue, teeth and other parts of the anatomy used to produce speech, called subvocal articulators”) or using a “distract and engage” strategy. The most effective distractions are—not surprisingly—“verbal or musical, such as chanting a mantra, reciting a poem, listening to a different song, even playing an instrument.” If none of that works for you, experts say, “the best strategy may be to [simply] enjoy the concerts in your head”! Medically, researchers continue to discover new ways to use sound. For those with a diagnosis of “essential tremor,” or even Parkinson’s Disease, there is “an experimental new treatment called focused ultrasound, or FUS.” The lowest sound any of us can hear is about 20 Hz; the highest is about 20,000. Any sound above what we can hear is, by definition, ultrasound. Some of the energy of sound waves will be bounced back from the tissues it encounters in a human brain. These echoes are used to create pictures the same way sonar uses reflected sound waves to map the watery depths. But some energy is absorbed by the tissues; usually ultrasound conveys so little energy that it does no harm, but at high energy levels, the FUS can create a powerful effect known as “inertial cavitation” in which the sound waves interact with dissolved gasses in tissue fluids, producing tiny bubbles that oscillate back and forth. As these bubbles begin to collapse, inertial cavitation sets off shock waves that can damage, or even liquefy the adjacent cells. FUS works by concentrating the power of hundreds of ultrasound beams on a single spot. Phased-array systems have been developed to coordinate the timing, or phase, of the sound waves to correct for the diffraction caused by the skull’s irregular shape—and because the brain feels no pain, the procedure is completely painless! Next, do you want an explanation for why birds sing in the morning? OK, scientists have proposed that “vocally warming up puts more dazzle into a bird’s singing for the day, perhaps helping to explain outbursts of birdsong at dawn.” One species of warblers in Puerto Rico “start trilling through their repertoires of 30 or so songs while it’s still pitch black. In the early versions of particular songs, males didn’t quickly change pitch as well as they did later.” And, “Males warming up sooner would fare better in mate competition. Over time, an arms race could have broken out as earlier warm-ups were beaten by even earlier ones.” Musicians competitive? Say it ain’t so! OK, that was all about competition, but what about cooperation? “When asked the right way, a savvy bird species steers African hunter-gathers to honey.” Birds known as greater honeyguides (Indicator indicator) lead Yao hunters in Mozambique to honey-rich bees’ nests when the humans make “a loud trill followed by a grunt that sounds like “brrr-hm.” The birds respond to the human call by making a loud chattering sound, and then fly from tree to tree until reaching one with a bees’ nest. Angry bees can and do sting honeyguides to death, so the collaboration is beneficial to the birds as well as the humans, who cut down the tree to bring the high-up nest down to ground level where they can smoke out the bees with flaming bundles of twigs and leaves. The Yao leave beeswax behind for the honeyguides and even put wax chunks on beds of leaves to reward their avian helpers. Researchers say this is the first solid evidence of two-way, collaborative communication between humans and a nonhuman animal in the wild. Just for fun, a folklorist and an English professor have collaborated to create a genre of perceptual and cognitive ruses that they have dubbed “folk illusions” [See Scientific American Mind, Sept/Oct 2016 edition, if you’re interested in more]. This one is called “church bells.” They found a reference to this game in a text from the early 1600s, and it is still played today. Use either a wire coat hanger, or a metal oven rack (which produces a more powerful effect): cut two pieces of string, tie them to the metal on opposite corners, and wrap the loose string ends several times around your index fingers. Put your index fingers in your ears and have someone strike the metal object; you will hear the sound of a church bell! “The illusion relies on the mechanical transmission of the vibration from the metal to the strings, then to the hands and skull bones, and finally to the fluid inside the cochlea in the inner ear.” One researcher says, “Even when you anticipate that it is going to work, it is still so surprising when it does happen.” Finally, in celebration of the continuing exploration of our solar system, go here to listen to the planet Jupiter “sing.” It’s accompanied by a “voice print” displaying what you hear (approximately 13 hours condensed into a few seconds).