That’s the broad-­strokes story of sound processing. But it remains surprisingly unclear how exactly our perceptual system differentiates these sounds within the auditory pathway. Certainly there are clues: music and speech waveforms have distinct pitches (tones sounding high or low), timbres (qualities of sound), phonemes (speech-sound units) and melodies. But the brain’s auditory pathway does not process all those elements at once. Consider the analogy of sending a letter in the mail from, say, New York City to Taipei. The letter’s contents provide a detailed explanation of its purpose, but the envelope still must indicate its destination. Similarly, even though speech and music are packed with information, our brain needs some basic cues to rapidly determine which regions to engage.