The author writes about the evolution of artistis interests: As kids, "we were young animals overflowing with want. We were chimpanzees holding out our hands. "The arts," as we practiced them, were a way to converse with our brains about the yearning." The yearning here refers to the desire to express ourselves but struggling to do so effectively.
It makes sense then, that artistic interest goes hand in hand with creativity, because when you have an overflow of ideas, you really want to express them instead of holding them all in!