The Lost Golden Age: Was Ancient Humanity Greater Than We Are Today?

Nearly every ancient culture on Earth tells the same story: that long ago, humanity lived in a golden age - a time of peace, wisdom, and abilities far beyond our own - before something went terribly wrong and we fell. The Greeks called it the Age of Gold. The Hindus called it the Satya Yuga. The Bible remembers Eden. Why would peoples who never met all preserve the same memory of a lost, higher world?