A high school project goes viral
In May 2018, a deceptively simple audio clip divided the internet. The phenomenon began when Katie Hetzel, a 15-year-old freshman at Flowery Branch High School in Georgia, was working on a vocabulary project. She played the audio pronunciation for the word "laurel" from Vocabulary.com and heard something entirely different: "yanny". When she asked her classmates, their perceptions were split, sparking a local debate that soon went global.
Hetzel posted the clip to her Instagram story on May 11, 2018. A senior at the same school, Fernando Castro, then republished it with a poll, and another friend, Roland Szabo, posted it to Reddit. From there, it was picked up by YouTuber Cloe Feldman and spread rapidly across Twitter, where a poll of over 500,000 respondents showed a near-even split: 53 percent heard "Laurel" and 47 percent heard "Yanny". The original recording was made in 2007 by an opera singer, Jay Aubrey Jones, who recorded approximately 200,000 words for the vocabulary website. The viral version, however, was a low-quality re-recording of the website's audio being played through speakers, which introduced the critical ambiguity.
The acoustics of ambiguity
The "Yanny or Laurel" clip is an example of a perceptually ambiguous stimulus, similar to visual illusions like the Necker cube or the face/vase illusion. Scientific analysis of the audio file's spectrogram—a visual representation of sound frequencies—reveals that acoustic cues for both words are present simultaneously. The lower frequencies of the recording form the acoustic pattern for "Laurel," while the higher frequencies carry the sonic information for "Yanny".
What a person hears depends on multiple factors. Age is one significant variable; as people get older, their ability to perceive high-frequency sounds often decreases, a condition known as presbycusis. This makes older listeners more likely to hear "Laurel". Hardware used for playback also matters. Different speakers and headphones can emphasize bass or treble, altering which set of frequencies is more prominent.
The brain determines the perception. When faced with an ambiguous signal, the brain attempts to find the "best fit" based on past experience and expectation. This is called top-down processing, or priming. If you expect to hear "Yanny," your brain is more likely to focus on the high-frequency data and perceive that word. Researchers like Brad Story at the University of Arizona confirmed that the low quality of the recording is what creates the ambiguity, allowing the brain to interpret the similar sound patterns in two different ways.