the need to keep everyone's interest up, says Richman, produced modern language's multifaceted structure. With- out it, human speech might have followed another course: the continu- ous gradings of voice and meaning found among most primates.
In the wild, such grading has certain advantages. It allows primates to shift quickly among social functions: from threatening to soliciting to submitting. But the range is limited. Choral music, on the other hand, cultivated an appreciation of "discrete...