specified,such as our capacity to perceive differences among melodies,
to hum a tune,and to extract emotion from a musical composition.Such
mechanisms also guide and constrain subsequent experiences,as we
learn to play an instrument or sing,each of us with different degrees of
skill and expertise.Most forms of musical performance require conven-
tions,formalized symbolic notation,or coordinated action,often led by
one individual (e.g.,a conductor leading the orchestra,a mother singing
with her child).Our curiosity and creative impulses,however,give us a
capacity to break conventions,sometimes resulting in success and some-
times in failure.
In this chapter I discussed some of the mechanisms underlying primate
vocal communication.Based on our research with rhesus monkeys and
other species,it appears that several components of our own musical
capacity have been in place for a long time.Some of them may have
evolved independently several times,suggesting convergent evolution.
In the case of primates,however,it seems likely that similarities with
humans represent homology,characteristics shared by a common ances-
tor.Specifically,I propose that humans and nonhuman primates share
three critical mechanisms,with some admittedly important differences
in their form and function.First,some nonhuman primate vocalizations
encode information about affective state and external referents.Listen-
ers are sensitive to such information and use it to classify salient objects
and events.Second,for some vocalizations,use is guided by a conven-
tion of sorts.Violators of the convention may incur significant costs if
they are caught by group members.Third,hemispheric biases underlie
the production and perception of vocalizations.
It would be misleading to conclude from the data presented that,
because of these underlying mechanisms,nonhuman primates have the
capacity to produce music.Many primate vocalizations are certainly
musical in that they sound,to the human ear,like a melody,one that
could readily be incorporated into a formal composition.But in the same
way that a piano and a sheet of music require a piano player,the neu-
rocognitive substrates of a monkey or an ape must similarly be com-
mandeered by a musician.The problem is to figure out what kind of
mechanism evolved to take advantage of the existing substrate for music
performance,perception,and appreciation.The end product of this evo-
lutionary fusion of mechanisms was the emergence of a species with a
musical sense.Acknowledgments
Funding for this research was provided by an NSF-Young Investigator
Award, NSF-Physical Anthropology, National Geographic Society,98 Marc D.Hauser