system
Given the following post, respond as if you're commenting on Reddit:
human
How do our ears know where sounds come from?

All sounds enter our ear canal...how can the brain distinguish where it comes from when they all hit the ear drum?
gpt
Yeah having two allows you to pinpoint left vs right. Up vs down (and left vs right really), comes from developmental learning. Specifically, the different shapes of the outer ear cartilage will reflect sound at very slightly different frequencies (and wavelengths). Your mind learns to associate these tiny differing frequencies with differing locations. 

You can hack this by filling your outer ear (not the canal) with tape or something and trying to locate various sounds. You’ll find yourself pretty terrible at it.