Three years ago, the great dress debate went viral. Now, a short audio clip of a robot voice saying either “Yanny” or “Laurel” (or both) is diving the internet—and social media users cannot agree on which one is correct.

In a video shared on Twitter by Cloe Feldman, the vlogger and social media influencer asked users, “What do you hear?! Yanny or Laurel,” with the accompanying recording and a video of the original Instagram poll. Thousands of people responded to the audio clip, which appeared on Reddit last week, with their answers—and the recording soon went viral. At the time of this writing, the audio clip has been heard more than 3.6 million times and many have weighed in with what they believe is the right word.

“Yanny….I listened 10 times and cant figure out how anyone hears laurel,” one Twitter user wrote in response to the tweet. Another user agreed, saying, “It’s 100% yanny how could it possibly be laurel.” Many people, however, were not convinced. “lau-rel. where is the yanny. WHAT IS A YANNY,” one person tweeted, while another wondered whether it was all just one big joke: “I hear Laurel. I’m not sure how you could hear anything else…wait is this a joke I don’t get?” Other people likened it all to another viral debate with one user commenting, “It’s The Dress but for linguistics, halp.”

See how social media reacted to the viral audio recording below:

Social Media Weighs In on Viral Yanny vs. Laurel Audio Clip

Some people clearly heard “Yanny” in the audio clip:

Others distinctly heard “Laurel”:

Many people also said they could hear both:

So what’s the deal? Well, according to Lars Reicke, an assistant professor of audition and cognitive neuroscience at Maastricht University, the answer lies in the frequency and perception of the audio.

The Verge reports, “The acoustic information that makes us hear Yanny is higher frequency than the acoustic information that makes us hear Laurel. Some of the variation may be due to the audio system playing the sound, Reicke says. But some of it is also the mechanics of your ears, and what you’re expecting to hear.” The recording can also sound different depending on the listener’s age.

Similar debates have happened over the years. In 2015, “The Dress” went viral as social media users were divided over whether a cocktail dress was gold and white or blue and black. The nail polish-shoe color and Adidas jacket debates followed. Social media users were also divided in 2016 over the color of a Kate Spade purse. The viral “Yanny-Laurel” recording is the first audio clip to divide the internet.

Do you hear “Yanny” or “Laurel” in the audio clip? Which viral social media debate has been your favorite? Sound off in the comments section below!