Laurel or Yanny — why do we hear things differently?

It’s the dress debate of 2015 all over again.

But this time, the question is — what do you hear?

A short clip originally posted on Reddit has people divided on what they’ve just heard.

Is it Yanny or Laurel?

Dr. Nicole Rosen, an associate linguistics professor at the University of Manitoba, said she hears Laurel, but it depends mainly on the frequency people are hearing it.

“There are two different sounds on top of each other, and it was really dependent on what you heard. Were you hearing the higher frequencies better or the lower frequencies?” she said. “That could have to do with your hearing or it could also have to do with what you’re listening to it on. Good headphones, bad headphones, a phone — that kind of thing.”

Altering the pitch will also vary people’s responses.

READ MORE: ‘Yanny’ or ‘Laurel’? The recording that’s dividing the internet

Regardless of the initial answer, the clip with its pitch dropped sounds like Yanny. Bumped up, it sounds like Laurel.

“People have been able to force themselves to pay attention to the different frequencies and then they say first it was just Laurel, then they paid attention and now all they can get is Yanny, and they can’t get Laurel back,” Dr. Rosen said.

She said she hasn’t listened to the altered versions of the clip, but has instead been studying the spectrograms, which are visual representations of acoustic sounds.

“I’ve seen how [the spectrograms] pick that apart, and they show that the formants, which is what is telling us what the sound is, how they’re both sort of superimposed on there,” Dr. Rosen said.

“If you clip out the bottom, then you see more clearly where the Laurel is coming from, and if you see from higher, then you see a bit more where the Yanny is coming from.”