Beyond Yanny or Laurel: 6 Other Aural Illusions and How They Work

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You know can't always believe your eyes, as optical illusions—or "brain failures," as Neil deGrasse Tyson calls them—make clear. It turns you can't always believe your ears either. Recently the internet went nuts over a four-second audio clip that sounded like "Yanny," "Laurel," or both. Audiologists contend that the clip has two distinct tracks laid on top of each other at different frequencies. Scientists call this an aural illusion—and it's not the only one. Here are six others that will make you doubt what you hear.

1. BRAINSTORM OR GREEN NEEDLE

The Illusion: Twitter users bored with the Yanny/Laurel question have been sharing this equally divisive clip. Some people think the garbled recording says "brainstorm," while others hear "green needle." Many have discovered that their thoughts can change the outcome. If you repeat the phrase "green needle" in your head, that's exactly what you'll hear when you listen to the clip. But if you've got "brainstorm" on your mind, then "brainstorm" is the term your ears are going to pick up.

How It Works: The video is a clip from a 2014 YouTube toy review. Uploaded by critic DosmRider, it's about a plastic space station from the Ben 10 collectibles line. The playset comes with a loading dock for action figures that trigger different sounds when they get plugged in. A crab-like character called Brainstorm is represented by one of these models. Put him on the station, and his name blares from the speakers. While listening to the soundbite, many people thought the toy was saying "green needle."

The clip contains a variety of different acoustic patterns—some of which are consistent with the term "green needle" while others match "brainstorm." Your expectations of which words you'll hear—coupled with the low-quality audio—do the rest. "When faced with an acoustic signal which is somewhat ambiguous because it is low-quality or noisy, your brain attempts a 'best fit' between what is heard and the expected word," Valerie Hazan, a professor of speech sciences at University College London, told The Telegraph.

2. SHEPARD TONES

The Illusion: In the above video, you hear what sounds like a single, perpetually swelling tone. A common fixture in the movie scores of composer Hans Zimmer, whose work you've heard in films like Dunkirk and Interstellar, this effect makes us believe that we're hearing the impossible: sounds whose pitch seems to rise endlessly without ever peaking or actually getting louder.

How It Works: The clip is in fact three separate sounds being played together—what are called Shepard tones. Each of these is an octave higher than the one beneath it. When separated into individual tones, as this Vox video explains, you can hear that the highest tone fades in volume, the middle one remains constant, and the lowest one increases. Because we're constantly hearing two upward-moving waves, we convince ourselves that the three-layered sound (taken as a whole) is growing higher and higher at a steady pace. It works for tones moving down in octaves as well.

3. CIRCLES, BEEPS, AND SENSORY CONFUSION

The Illusion: The opening 15 seconds of this video contain two multisensory displays. In the first, a lone black circle flashes onto the screen. This is accompanied by one high-pitched beep. You will then see the exact same thing happen again, with another solitary black circle popping into view. But this time, there will be two beeping sounds instead of one. Even though the animation is identical in both runthroughs, some viewers think they can see two flashing circles in that second display.

How It Works: Dubbed the sound-induced flash illusion by its discoverers, the trick plays on the fact that your brain sometimes consults other senses to figure out what your eyes are seeing. That's how the back-to-back beeps can fool you into mistaking a single flash for two separate ones. Some people might be especially vulnerable to the illusion. A 2012 study found that in a pool of 29 volunteers, nearly everyone reported seeing the second flash in at least a few trial runs. However, participants with small visual cortexes—a region of the brain which deciphers optical signals—saw it way more often than their peers did.

4. THE MCGURK EFFECT

The Illusion: In the previous entry, sound may have changed what you saw. In this one, seeing might change what you hear. A man says "bah" over and over. Or does he? Turn off the sound and see the shape his mouth makes as he speaks. He's actually saying "fah."

How It Works: First documented in the 1970s by researcher Harry McGurk [PDF], the McGurk Effect involves an incongruence between audio information and visual information. The brain's desire to reconcile these incongruent inputs is so strong, it can change what you hear to align with what you see.

5. SPEECH TO SONG

The Illusion: Diana Deutsch, who teaches at the University of California, San Diego, is an authority on the psychology of music. One day in 1995, Deutsch was editing an audio lecture she'd recorded. The sentence fragment "sometimes behave so strangely" was playing on a loop in her office. As she heard repeated over and over again, the phrase began to sound less like talking (which it was) and more like singing. It's had the same effect on other people. In the above video, notice how, after a certain point, this spoken-word recording picks up a musical quality, even though the speaker never actually sings.

How It Works: It's a phenomenon Deutsch has named the speech-to-song illusion. Repetition is a core component of all music, and it seems our brains try to create little melodies out of statements or sounds repeated to excess. How or why this occurs isn't completely understood. As future experiments dissect the illusion, psychologists may learn new things about how the mind organizes and processes the things it perceives [PDF].

6. PHANTOM WORDS

The Illusion: Once you click play on the video above, some bombastic, repeating syllables are going to hit your eardrums. For best results, place yourself between two speakers, but a decent set of headphones should also do the trick. Amidst this aural onslaught, your mind will probably identify some recognizable words or phrases. Test subjects who've listened to this have reported hearing words such as "no brain," "window," "raincoat," "mango," and "Broadway."

How It Works: Have you ever looked at a bowling ball and thought the three holes on its side resembled a human face? That's called pareidolia. Something like that is going on here. We're hard-wired to seek out patterns, both visually and aurally. There are two tracks in this audio clip, with each containing an ambiguous word or two. These sounds mix together in the air and then reach your ears as an unrecognizable racket. Listen long enough, and sooner or later you'll begin to hear "phantom words"—words or statements that aren't really being said. Since humans crave patterns, we force ourselves to hear them.

This experiment was another brainchild of Diana Deutsch's. She's found that the phantom words a person hears are liable to reflect their current mood. For example, weight-conscious test subjects might hear food-related terms.

Running Just Once a Week Is Linked to a 27 Percent Drop in Risk of Early Death

lzf/iStock via Getty Images
lzf/iStock via Getty Images

A new study suggests that even the occasional light jog could help you live a longer, healthier life.

Runner’s World reports that researchers compiled data from 14 previously published studies to determine if running was associated with lower the risk of early death. Their findings, published in the British Journal of Sports Medicine, show that among a pooled sample of 232,149 people whose habits were monitored from 5.5 to 35 years, those who ran had a 27 percent lower risk of early death than those who didn’t.

Causes of death included cardiovascular disease, cancer, and everything in between—and while the study doesn’t guarantee that running will lower your risk of early death, it does show that there’s at least a link between the two.

Furthermore, the results suggest that you don’t have to be a particularly dedicated or serious runner in order to reap the health benefits. The researchers found that those who ran for less than 50 minutes a week, only once a week, or at speeds below 6 mph still ranked with more intense intense runners when it came to lower early death rates than non-runners.

“This finding may be motivating for those who cannot invest a lot of time in exercise, but it should definitely not discourage those who already engage in higher amounts of running,” Željko Pedišić, a professor at Victoria University’s Institute for Health and Sport and a co-author of the study, told Runner’s World.

In other words, there’s no reason that avid marathoners and competitive tag enthusiasts should lessen their running regimens—but if you spend most of your time sitting in front of your computer or television, you might want to consider adding a 45-minute neighborhood jog to your weekly to-do list. According to Pedišić, it could help keep high blood pressure, high cholesterol, obesity, cardiovascular disease, type 2 diabetes, and cancer at bay.

And if you’re avoiding running to protect your knees, toenails, or something else, you probably don’t have to—read up on the truth behind eight common running myths here.

[h/t Runner’s World]

The Best Place to Park at the Mall, According to Science

Diy13/iStock via Getty Images Plus
Diy13/iStock via Getty Images Plus

It’s Black Friday, and you are entering the battlefield: a mall parking lot. You’re determined to nail that doorbuster deal, and quantities are limited. The field is already full of other combatants. You must find the perfect parking spot.

Do you grab the first one you see, or drive as close to the mall as you can and hover? Or, do you choose a tactic that lies somewhere between?

Parking at the mall has long frustrated drivers and taxed the minds of traffic engineers—but after working on the problem for three years, physicists Sidney Redner of the Santa Fe Institute and Paul Krapivsky of Boston University have gotten closer to a winning strategy. “There are lots of studies of parking lots, but it’s just that they’re so complicated, you don’t get any insight into what’s actually happening,” Redner tells Mental Floss.

Redner and Krapivsky, whose work employs statistical physics to make sense of large systems, simplified the messy dynamics of a parking lot by modeling it with a one-dimensional grid of cells, each representing a parking space. They tested three simple, yet realistic, parking strategies using basic probability theory. Their model tested the following strategies to see which one resulted in least time spent walking and driving in the parking lot:

Meek Strategy: Meek drivers park in the first open space they see, however distant it is from the mall. As a result, they often spend the most time walking to and from the mall.

Prudent Strategy: Prudent drivers look for the first open spot but then keep driving toward the mall. They continue to drive until they see a parked car and then park in the best open spot between that first open spot and that first parked car. There may be a block of open spaces between the first open space and the first parked car. From that block of open spaces, they choose the one closest to the mall.

Optimistic Strategy: Optimistic drivers drive as close to the mall as possible and look for a parking space close to the entrance. If they see one, they grab it. If there are none, they backtrack and choose the first open space they see. Optimistic drivers probably spend the most time driving and the least time walking. In the worst-case scenario, they end up parking back where a meek driver would have parked.

Naturally cautious drivers are more likely to default to the meek mode, while aggressive drivers often use the optimistic strategy, well, aggressively. And most drivers have tried something like the prudent method.

So, which is your best bet in a crowded mall parking lot this holiday season?

In the experiments, the prudent strategy fared best, followed closely by the optimistic strategy. The meek strategy finished a distant third (“It’s hard to comprehend just how bad it is,” says Krapivsky, a self-described meek driver).

And even better: The more crowded the lot, the better the prudent strategy works, he adds.

One clear takeaway from the study is that meek drivers may want to ramp up their parking skills before going to the mall. “You don't want to park on the very outskirts of the lot, like a mile away from the stores. You want to go to the first place there’s an open spot and park somewhere in that first open area,” Redner says. They published their findings in the Journal of Statistical Mechanics [PDF].

The researchers say this is the best of the strategies they tested, but it has its limitations. It does not take into consideration competition among a sea of drivers all looking for parking spaces at the same time, and it doesn’t include (perhaps optimistically) the psychological aspects of operating a vehicle. “We are not rational when we are driving,” Krapivsky tells Mental Floss.

The researchers’ one-dimensional grid model also assumed that there would be one car at a time entering the lot through one entrance, unlike messier lots in the real world, where many cars enter from a multitude of entrances.

The optimal parking strategy, one that would best all others every time, has yet to be found. In their research, though, Redner and Krapivsky are homing in on one that integrates the more complicated aspects of parking.

For now, science says prudence is a virtue in the parking lot. And while the meek might inherit the Earth, they certainly won’t find the best parking space at the mall.

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