Ask Marilyn

Since we have two ears, I can understand how we can tell whether sounds are coming from our left or right. But how can we tell if they’re coming from our front or back? —Don Phillips, Cypress, Calif. As those two ears are on opposite sides of our heads, they provide us with a great many clues about the location of the source. Even the tiniest differences in volume, timing, frequency and reverberation give us data. And all of our senses are in play: Anything we can see or feel adds to what our brains perceive from our hearing. Also, without giving it a moment’s thought, we simply turn or tilt our heads to pick up even more information.