The Origins of Music: Preface - Preface

observation MacLarnon (1993) and Walker (1993) contend that smaller

arches may indicate an underdeveloped muscular control of breathing

and consequent incapability of language at this period of human

evolution.

This conclusion contradicts other indications pointing to linguistic

ability in the same specimen,such as a large brain size with petalial and

other left-right brain asymmetries.Moreover,chimpanzees with small

neural arches have adequate intercostal muscle control to generate

sounds with complex pitch,intensity,and volume (Goodall 1986;Marler,

this volume).Other explanations are proposed for the small neural

arches in WT-15000.For example,Wolpoff (1996:403) reviewed unpub-

lished work by Childress who postulated that the arch dimensions

relate to underdeveloped neural control of hand movements.Another

researcher theorized that the small size relates to reduced capacity to

“send and receive neural messages to his lower extremities”(Mackway-

Girardi 1997).It is hard to accept either of these speculations.The only

cervical vertebra preserved in WT-15000 is C7,and the neural canal on

this bone is not reduced (MacLarnon 1993:371).Since most of the

muscles involved in speech respiration are innervated by either cranial

or cervical nerves,there is no evidence that these were smaller,since the

vertebrae are not preserved.Similarly,arm and hand movements are

controlled by the brachial plexus,and no evidence exists for reduction

in these areas,since MacLarnon (1993) reported reduced neural arches

in only thoracic portions of the vertebral column.As for reduced bipedal

capacity,no evidence from any other area of the skeleton points to

lowered locomotor ability.Hunley (1998) confirmed the small size of the

thoracic canals,but when cranial capacity is considered,WT-15000

226 David W.Frayer and Chris Nicolay

Figure 14.3

Thoracic cages typical of humans and chimpanzees.The rib cage in modern humans is

barrel-shaped and that in chimpanzees resembles a lampshade.The barrel-shaped rib cage

appears at least by 1.6mya in early Homo.(Modified from Schultz 1969:66.)

Fig.14.3