KRIS: Hey, Sagarika.

SAGARIKA ALAVILLI: Hey, Kris.

KRIS: Teach me something.

SAGARIKA ALAVILLI: Do you know how people localize sounds?

KRIS: No.

SAGARIKA ALAVILLI: So we use a combination of different cues to do this. For the x-axis or azimuth, we use binaural cues. We use both of our ears. The first is interaural time difference or the time difference between your ears. So if the sound's coming from the right, it's going to hit your right ear first. The other is interaural level difference or loudness level difference between our ears. So if the sound's coming from the right, it's going to be louder in your right ear.

For the y-axis or elevation, we use pinna cues. This is our pinna right here, or our outer ear. And the pinna changes the sound signal depending on where a sound is coming from. And these are specific to each individual person and you learn these over time. So if your pinna were to change for whatever reason, you'd actually have to relearn these cues, and your localization accuracy would drop in the meantime.

This can get really complicated for situations with background noise or multiple sounds. And we don't fully know how that's done yet. And so we can use cool tools like this speaker right behind me to test that.