Why a minor chord sounds sad

Play three notes together and you get a chord. Move just one of those three notes down by the smallest step on a keyboard, and a bright, hopeful sound turns wistful. That's the entire difference between major and minor.

Flip the switch and press play. The outer two notes never move — only the middle one slides down a single key for "minor."

The middle (orange) note is the one that drops. Tap any key to hear it alone.

It's a tiny move — one semitone, the closest two notes can be — but your ear hears it instantly. In Western music we learn from childhood to read that lowered third as "sad" and the higher one as "happy," and the brain responds before you can name what changed.

What single change makes a chord sound sad?

This "happy/sad" reading is mostly learned, not universal — some cultures hear it the opposite way. Want to hear what happens to a whole melody, or why a seventh chord sounds jazzy? Ask me in the chat.

Primary source · BBC Science Focus — Why are minor chords sad and major chords happy?