Romantic love was invented by troubadours during the Middle Ages. You might have heard that before. Until recently, that view was widely held by anthropologists, sociologists, and historians: Love is a western cultural construct. Now, most researchers believe love is a cultural universal. Literature, music, and artifacts from everywhere and every time show humans falling in love. But why do we fall in love? Why does love cause us transcendent joy? Why is it devastating when our relationships fall apart?