It's the audio equivalent of the white or blue dress that perplexed the internet in 2015: Is the voice in this clip saying "Yanny" or "Laurel"? Many people—including the musician Yanni—insist it says Yanny, while others, including this writer, clearly hear Laurel. Others claim to have heard one, then the other, while some say they heard both words simultaneously, the New York Times reports. The auditory illusion, which went viral on Tuesday, was first posted by Instagram user Cloe Feldman, and a poll on her page had about 51% people in favor of Yanny, though polls elsewhere have Laurel narrowly in the lead, reports the Atlantic.
As with the contentious dress, many experts have been coming forward with their opinions on the Laurel versus Yanny debate. Professor David Alais at the University of Sydney's School of Psychology tells the Guardian that it's an example of a "perceptually ambiguous stimulus." "They can be seen in two ways, and often the mind flips back and forth between the two interpretations," he says. "This happens because the brain can't decide on a definitive interpretation." Other experts noted that the acoustic patterns in the clip seemed to be halfway between the two words, and people were more likely to hear a different word when the pitch, bass, and volume were adjusted. (Read more viral video stories.)