‘Yanny,’ ‘Laurel’ and other sound illusions

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May 16, 2018

Two unrelated words, “Yanny” and “Laurel,” are splitting the internet in half. An audio clip (below) of a robot voice picked up steam after a debate erupted on Reddit this week, and it has since been circulated widely on social media. Some people who listen to the audio file hear one thing, and others hear something completely different.

It’s like an audio version of "The Dress," a photo that went viral in 2015 when no one could agree whether the garment shown was white and gold or blue and black. As with the Yanny-Laurel clip, nothing at first seems wrong, until you start talking to somebody about your experience and discover that their sensation is completely different from what you experienced.

So why are people hearing different things?

The poor quality of the four-second recording allows for many reasons why people could be hearing different things. The device you listen to the clip on impacts your interpretation, as well as the frequency at which your brain latches onto sound. Because the speech sounds in this clip are ambiguous, both interpretations are valid: It just depends which components of the sound your brain focuses on.

Other explanations for sound illusions

Sound illusions like the Yanny-Laurel illusion are interesting because they show how the brain works to interpret incoming information and assumptions so that they make sense. Pieces of this illusion can potentially be explained by the perceptual phenomenon called the McGurk Effect, which demonstrates the interaction between hearing and sight.

The McGurk Effect occurs when there is a conflict between visual speech, the movements of someone's mouth and lips, and auditory speech, the sounds a person hears. And it can result in the perception of an entirely different message.

The effect was first described in an experiment done in 1976 by psychologists Harry McGurk and John MacDonald. In the demonstration of the McGurk effect used in the study, a participant was asked to keep their eyes closed while listening to a video that shows a person making the sounds "ba ba ba." Then the participant is asked to open their eyes and watch the mouth of the person in the video closely, but with the sound off. Now, the visuals look like the person in the video is saying "ga ga ga.”

In the final step of the experiment, the same video is replayed, but this time the sound is on, and the participant is asked to keep their eyes open. People who are sensitive to the McGurk effect will report hearing "da da da" — a sound that doesn't match up with either the auditory or visual cues previously seen.

This happens because the brain is attempting to resolve what it thinks it's hearing with a sound closer to what it visually sees. If the person closes their eyes again, and the video's sound is replayed, they’ll once again hear "ba ba ba."

The McGurk Effect and hearing loss

The McGurk Effect is something that we deal with every day, but don’t really talk about. It’s also has more to do with your brain’s central processing than what you’re hearing.

When people are having a face-to-face conversation, the brain is engaged in complicated activity as it tries to decide how to put lip movements together with the speech sounds that are heard.

For those that have hearing loss, it takes a lot more brain power to decode these visual signals.

The McGurk Effect shows us that reading lips is effective for those with hearing loss because visual cues are very important. For those with minor hearing loss, reading lips can be a valuable way to maximize the hearing they still do have. Also, this reveals more about why watching the mouth is so important in intense language learning.

If you do find yourself struggling to hear, Ohio State can help. Learn more about how we can help you and your family.

Dr. Oliver Adunka is the director of Otology, Neurotology and Cranial Base Surgery at The Ohio State University Wexner Medical Center and director of the Otology and Hearing Program at Nationwide Children’s Hospital in Columbus, Ohio.