The Origins of Music: Preface - Preface

the coconut,he gave two harmonic arches.In contrast to the first panel,

this sequence represented a change in call type as well as some within-

call type changes in structure.Our current hypothesis,based on such

cases,is that rhesus monkeys experience changes in emotional state as

they approach and then eat food.Such changes may also lead to changes

in more coarse-grained morphology as they shift from one call type to

another.

Natural observations also revealed systematic differences in the con-

texts eliciting each call type.In particular,warbles,harmonic arches,and

chirps were produced only by individuals finding high-quality,rare food

items,coconut being one of these.Grunts and coos sometimes accom-

panied other call types,but were primarily given in response to finding

and eating lower-quality,common items such as chow.Time of day (as a

proxy for hunger level) had no effect on the type of call produced.Only

food type did.These results suggest that the characteristic spectral and

temporal morphology of the call maps onto something like food type or

82 Marc D.Hauser

Figure 6.2

Upper panel shows changes in acoustic morphology of the rhesus coo vocalization as a

function of proximity to chow.The y axis plots frequency in kilohertz,the x axis plots time

in seconds.The lower panel plots changes in call structure and type as functions of move-

ment toward coconut.

Fig.6.2