Yanny vs. Laurel spotlights our brains’ desire to fill in the gaps

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• Judy Woodruff:

  And now to our "NewsHour" shares, something interesting that caught our eye.

  Yanny vs. Laurel, it's the auditory debate taking the Internet by storm today.

  "NewsHour"'s Nsikan Akpan and Julia Griffin explain how one sound can create two different experiences.

• Julia Griffin:

  The Internet has been set ablaze over one sound and two words.

  (SOUND PLAYING)

• Nsikan Akpan:

  So, which did you hear, Yanny or Laurel?

  This audio clip, which first went viral on Reddit and then Twitter, features a robotic voice saying a specific word, but people's perceptions of that word differ dramatically, even in the "NewsHour" office.

• Man:

  Yanny.

• Judy Woodruff:

  Laurel.

• Woman:

  Yanny.

• Woman:

  Yanny.

• Man:

  Laurel.

• Woman:

  Laurel.

  (CROSSTALK)

• Nsikan Akpan:

  How is it possible people are hearing different things? The sound is what's called an ambiguity illusion, and it's nothing new to neuroscientists.

• Julia Griffin:

  Remember the dress from 2015? Some people swore it was gold and white, others black and blue. That viral photo is a visual version of an ambiguity illusion.

• Nsikan Akpan:

  When a human brain encounters something it can't immediately understand, it tries to fill in the gaps.

• Julia Griffin:

  In the case of Yanny v. Laurel, the frequency, or pitch, of the sound clip is cryptic to our minds.

  The original poster of the audio clip, an 18-year-old Reddit user from Lawrenceville, Georgia, recorded the pronunciation of Laurel off Vocabulary.com through his speakers. That distorted the sound.

• Nsikan Akpan:

  This muddled sound causes our brains to fall back on their natural preferences.

• Julia Griffin:

  Folks who prefer lower frequencies hear Laurel, while those who lean toward high frequencies hear Yanny.

• Nsikan Akpan:

  This might explain why children are reportedly hearing Yanny. The human ability to hear higher frequencies fades with age.

• Julia Griffin:

  Your speakers or headphones may also be to blame, as some sound systems are tuned to emphasize different frequencies.

• Nsikan Akpan:

  People discussing the sound around you can also shift your mind's perception.

• Julia Griffin:

  Ambiguity illusions typically cause our perceptions to land one way or the other.

• Nsikan Akpan:

  Yanny/Laurel and the dress stand out because they clearly split a room.

• Julia Griffin:

  But the neurological basis for exactly why is still a mystery to scientists.

  For the "PBS NewsHour," I'm Julia Griffin.

• Nsikan Akpan:

  And I'm Nsikan Akpan.

• Judy Woodruff:

  And I don't know what the fuss is all about. It's Laurel.