BISTABLE PERCEPTION PART 1: Viral "Laurel" vs. "Yanny" Phenomenon

I do my best to ignore viral nonsense on the 'net. This new trend, the Yanny vs Laruel audio "mind game" actually captured my attention.  It's not at all mystical, nor are you going nuts because you only hear one word. It's all in how the ears work and the mind reacts.

Bistable Auditory Stimulus, also called "Bistable Stimuli" and "Bistable Perception" by some, amuses me.  I've experienced it several times in life.

The event that comes to mind when I heard BAS happened back in my teenage years.  I was Buddhist. We gathered as a group once a month to chant a six-word phrase which, after about ten minutes of being immersed in the sound, starts to play tricks on the ear.

"DOG is at the bowl now DOG is at the bowl now DOG is at the bowl now DOG is at the bowl NOW dog is at the bowl NOW dog is at the bowl NOW dog is at the bowl now." Nobody purposefully stressed the last word ("now") of the phrase.  The brain, lulled by monotony, simply interprets the sounds differently.

Bistable stimuli can be perceived in two separate ways. The sound you hear can be heard in two ways: as triplets of an A-B-A pattern or as two simultaneous streams of an A-A-A-A pattern and a B-B-B-B pattern.

Typically, discussions of illusory experiences focus on visual illusions. But auditory illusions (and illusions in other sensory modalities, including cross-modal ones) are also interesting. Illusions in general provide us with cases in which what we experience doesn't seem to match reality. If that's right, we are not experiencing reality, and we can ask what it is that we are experincing. If that's not right, then we can ask why we appear to experience something that doesn't match reality, and whether we really are experiencing what we take ourselves to be experiencing. Illusions in sensory modalities other than vision show us that this issue affects experiences in other modalities, such as audition, touch, taste, smell, and so on.

Another factor that plays into this is how your ears hear frequencies. As discussed in the video below, the original word is indeed "laurel". However, it is overlaid with higher frequencies to create ambiguity. It's all about pitch.

A few older people have reported that they don't hear anything at all - just garbled words - while those with quality hearing aids are able to hear both if they concentrate. Whether or not this reporting is accurate remains to be tested. It's the Internet. Don't believe everything you're told!

So how do frequencies and pitch come into play?

To get an idea, Steve Pomeroy shifted the pitch. (The links most likely will take you off this page. It's best to right-click, "open link in new tab".)

The structures responsible for frequency interpretation are the cochlear.

What is the function of the cochlea in the ear?  This occurs at the organ of Corti, which is located all along the cochlea. It is composed of sensory cells called hair cells, which convert vibrations into neural messages. These messages are then passed to the auditory nerve and carried up to the brain.

Take heart. Your inability to hear only "yanny" or "laurel" does not mean you should rush out for an audiogram. Enjoy the viral trend while it lasts.

As always, the information stated here is my opinion and not necessarily fact. 
Please don't hesitate to reach out to me if you have questions.  Bear in mind that I wax poetic regarding theories and hypothesis; the accuracy of my interpretation may be askew though I welcome positive critique and correction in the comments section.

Also, sorry, but I probably won't start making YouTube videos anytime soon. I get enough ribbing from Hummingbird, Bash, Yolandercuz, and Honey Badger regarding my "whiskey voice".  Hey, fam, you bastards keep smoking and you too can sound like me in 20 years. (At least Better Half doesn't tease me.)

For the record: I hear "yanny".