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

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iStock

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.

10 Facts About Rosacea

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Rosacea, a skin condition characterized by redness and swelling, is incredibly common: A recent study found that an estimated 300 million people worldwide suffer from it. Here’s what you need to know about the condition.

1. IT HAS A LONG HISTORY.

According to the National Rosacea Society (NRS), rosacea was first described in the 14th century by a French surgeon named Dr. Guy de Chauliac; he called it goutterose (“pink drop” in French) or couperose and noted that it was characterized by “red lesions in the face, particularly on the nose and cheeks.”

2. SCIENTISTS AREN’T SURE WHAT CAUSES IT ...

But they have some theories. According to the NRS, “most experts believe it is a vascular disorder that seems to be related to flushing.” Scientists also think that because rosacea seems to run in families, it might be genetic. Other things—like mites that live on the skin, an intestinal bug called H pylori (common in those who have rosacea), and a reaction to a bacterium called bacillus oleronius—could also play a role in causing the condition. One 2015 study suggested an increased risk among smokers.

3. … BUT SOME PEOPLE ARE MORE LIKELY TO HAVE IT THAN OTHERS.

Though people of all ages and skin tones can get rosacea, fair skinned people between the ages of 30 and 50 with Celtic and Scandinavian ancestry and a family history of rosacea are more likely to develop the condition. Women are more likely to have rosacea than men, though their symptoms tend to be less severe than men’s. But men are more likely to suffer from a rare rosacea side effect known as rhinophyma, which causes the skin of the nose to thicken and become bulbous. It’s commonly—and mistakenly—associated with heavy drinking, but what exactly causes rhinophyma is unclear. According to the NRS, “The swelling that often follows a flushing reaction may, over time, lead to the growth of excess tissue (fibroplasia) around the nose as plasma proteins accumulate when the damaged lymphatic system fails to clear them. Leakage of a substance called blood coagulation factor XIII is also believed to be a potential cause of excess tissue.” Thankfully, those who have rhinophyma have options available for treatment, including surgery and laser therapy.

4. THERE ARE FOUR SUBTYPES.

According to the American Academy of Dermatology (AAD), rosacea “often begins with a tendency to blush or flush more easily than other people.” All rosacea involves redness of some kind (typically on the nose, cheeks, chin, and forehead), but other symptoms allow the condition to be divided into four subtypes: Erythematotelangiectatic rosacea is characterized by persistent redness and sometimes visible blood vessels; Papulopustular rosacea involves swelling and “acne-like breakouts”; Phymatous rosacea is characterized by thick and bumpy skin; and Ocular rosacea involves red eyes (that sometimes burn and itch, or feel like they have sand in them [PDF]), swollen eyelids, and stye-like growths.

5. IT’S NOT THE SAME AS ACNE.

Though rosacea was once considered a form of acne—"acne rosacea" first appeared in medical literature in 1814—today doctors know it’s a different condition altogether. Though there are similarities (like acne, some forms of rosacea are characterized by small, pus-filled bumps) there are key differences: Acne involves blackheads, typically occurs in the teen years, and can appear all over the body; rosacea is a chronic condition that occurs mainly on the face and the chest and typically shows up later in life.

6. YOU CAN FIND IT IN CLASSIC ART AND LITERATURE.

Both Chaucer and Shakespeare likely made references to rosacea. Domenico Ghirlandaio’s 1490 painting An Old Man and His Grandson seems to depict rhinophyma, and some believe that Rembrandt’s 1659 self-portrait shows that the artist had rosacea and rhinophyma.

7. IT MAY BE TRIGGERED BY CERTAIN FOODS AND ACTIVITIES.

According to the National Institutes of Health (NIH) [PDF], people report that everything from the weather to what you eat can cause rosacea to flare up: Heat, cold, sunlight, and wind, strenuous exercise, spicy food, alcohol consumption, menopause, stress, and use of steroids on the skin are all triggers.

8. THERE ARE A NUMBER OF MYTHS ABOUT ROSACEA.

No, it’s not caused by caffeine and coffee (flare ups, if they occur, are due to the heat of your coffee) or by heavy drinking (though alcohol does exacerbate the condition). Rosacea isn’t caused by poor hygiene, and it’s not contagious.

9. THERE ARE SOME PRETTY FAMOUS PEOPLE WITH ROSACEA.

Sophia Bush, Cynthia Nixon, Kristin Chenoweth, Bill Clinton, and Sam Smith all have rosacea. Diana, Princess of Wales had it, too. W.C. Fields had rosacea and rhinophyma, and Andy Warhol may also have suffered from those conditions.

10. IT CAN’T BE CURED—BUT IT CAN BE TREATED.

The NRS reports that “nearly 90 percent of rosacea patients [surveyed by NRS] said this condition had lowered their self-confidence and self-esteem, and 41 percent reported it had caused them to avoid public contact or cancel social engagements.” Dr. Uwe Gieler, a professor of dermatology at the Justus-Liebig-University in Giessen, Germany, and one of the authors of the report Rosacea: Beyond the Visible, said in a press release that "People with rosacea are often judged on their appearance, which impacts them greatly in daily life. If their rosacea is severe, the symptoms are likely to be more significant also, from itching and burning to a permanently red central facial area. However, even people with less severe rosacea report a significant impact on quality of life."

Which makes it all the more unfortunate that there’s not a cure for the condition. Thankfully, though, there are treatments available.

There are no tests that will diagnose rosacea; that’s up to your doctor, who will examine your medical history and go over your symptoms. Doctors advise that those with rosacea pay attention to what triggers flare-ups, which will help them figure out how to treat the condition. Antibiotics might be prescribed; laser therapy might be used. Anyone with rosacea should always wear sunscreen [PDF] and treat their skin very, very gently—don't scrub or exfoliate it. The AAD recommends moisturizing daily and avoiding products that contain things like urea, alcohol, and glycolic and lactic acids.

Endeavour, Captain Cook's Lost Ship, Might Have Been Found—Solving a Centuries-Old Mystery

Wellcome Images, Wikimedia Commons // CC BY-SA 4.0
Wellcome Images, Wikimedia Commons // CC BY-SA 4.0

The exact location of the final resting place of Captain James Cook’s HMS Endeavour, which was sunk off the coast of Rhode Island 200 years ago, is considered one of maritime history’s greatest mysteries. Now, after a 25-year effort to pinpoint its remains among 13 sunken vessels, The Age reports that the Endeavour might have finally been identified.

British explorer James Cook left England on the Endeavour in 1768 headed for the South Pacific. He and his crew became the first European expedition to map the entire coast of New Zealand, and later, the first to reach Australia’s east coast. Along the way, they collected hundreds of previously unknown plant species, became the first Europeans to record a kangaroo sighting, and gathered evidence that would help disprove the existence of the long-speculated southern continent, Terra Australis, that hypothetically extended all the way up to the equator.

A replica of the 18th-century 'Endeavour' in the ocean
A replica of the Endeavour in 2004
Dennis4trigger, Wikimedia Commons // CC BY-SA 3.0

After that three-year journey, Cook and his crew returned to England. Though Cook became a legend, the Endeavour didn’t receive the star treatment. The British Royal Navy used it to ferry supplies to and from the Falkland Islands for several years before selling it to a private buyer. The ship was renamed the Lord Sandwich, and was eventually put into service transporting German mercenaries to fight on Britain's side in the American Revolution.

That’s how the ship ended up in Rhode Island, where it was stationed as part of the Royal Navy’s fleet in Newport Harbor and used as a prison ship for captured American soldiers. When French reinforcements came to assist American revolutionaries in Rhode Island, the British decided to sink their ships rather than allow them to be captured, creating a blockade out of scuttled vessels to block the French from getting into the harbor. They sank 12 transport vessels and set another on fire. Over the ensuing years, locals and French forces took equipment from the wrecks, but it’s never been entirely clear what happened to the remains.

The Rhode Island Marine Archaeology Project began to try to map and identify those remains starting in the early 1990s, and eventually figured out that the Lord Sandwich was the same ship as the HMS Endeavour. As the ship played a vital role in Australian history, the Australian National Maritime Museum then got involved with the project.

The two organizations have announced that they have lowered the number of potential wrecks that could be the Endeavour from 14 to five—and perhaps down to just one—by inspecting the area and measuring the wrecks against historic information about Cook's vessel. The researchers think the final resting place of the ship is located off the coast of Goat Island in Narragansett Bay, but to be absolutely certain, they’ll have to excavate the remains of the ship and examine its timbers. The researchers hope to have that work done by the 250th anniversary of Cook’s arrival in Australia’s Botany Bay—and his claiming of Australia as British territory—in 2020.

And there may be a battle over the remains. While the ship is considered a vital artifact of Australian history, the state of Rhode Island claimed ownership of all of the sunken ships in 1999, and they are overseen by the Rhode Island Historical Preservation and Heritage Commission.

[h/t The Age]

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