Linguists describe the “deep structure” of language, referring to the innate rules that speakers of all languages follow, even though they may not realize that they are doing so. Similarly, music theorists describe the underlying structure of music—the way certain tones or chords or rhythmic patterns imply and affect others. The aim of my work for over thirty years has been to uncover some of the deep structure of the arts. That is to say, there are underlying principles of our nature as humans that influence the making of our own arts and our responses to the works of others. I will describe two sources for these underlying aesthetic principles. One is our prehistoric past when all humans lived as hunter-gatherers and faced common existential problems; the other is our past as individuals who all begin life as helpless infants. Universal emotional needs and artistic proclivities arise from our biological nature as humans and are intrinsic to who we are as individuals and as a species