Imagine you are standing in a field and hear a high-pitched whistle coming from directly overhead. Even though the sound reaches both of your ears at the exact same time and with the same loudness, you can still tell that the sound is above you, not in front of you. Which of the following best explains this ability?

Imagine you are in a quiet room and hear a faint, high-pitched buzz. You are able to determine that the sound is coming from directly above your head, rather than from in front of or behind you. Which of the following best explains how your auditory system determines the sound's vertical location in this specific situation?