LECTURES IN BIOLOGICAL SCIENCES 



(c) Intercortical— cannot associate its name with an ob- 

 ject seen nor associate its appearance with an objt ct 

 named. 



These results from the neurological study of aphasia show the 

 sensory, steering, and motor apparatus for articulate speech are 

 wired together in the cerebral cortex and cephalocentric systems. 



Visual communication by body movements or gestures is 

 poorly developed in the prosimians but highly developed in 

 monkeys and apes (Yerkes and Yerkes, 1929; Zuckerman, 1933). 

 Seemingly, a major part of all social communication in monkey 

 and ape bands is visual; vocalization is used mainly to attract 

 attention of animals not looking at the sender. Haldane (1955) 

 has remarked that imitation of visual signals is rare in animals 

 for the obvious reason that animals do not have mirrors. A 

 baboon cannot see itself snarl, and its postures look different to 

 itself than to others. But primates do hear themselves vocalize. 

 A call made by X produces sensations in X like a call made by 

 Y. There is feedback of vocalization via the ear. 



If we assume with Haldane (1955) that when X imitates Y's 

 call this tends to alter X's internal state in a way which leads to 

 performance of the action predicted by Y's signal, it is clear 

 that the ability to imitate vocal signals is of assistance in the 

 coordination of social action. We know that near-men hunted 

 and took large animals. It seems safe to assume that, once the 

 chase was on, vocal signals allowed members of the hunting 

 band to coordinate their activities while keeping the prey in 

 sight. The source of sound waves, with a wave length which 

 differs from the distance between the two ears of the hearer, 

 may be localized directionally. In this connection it is of in- 

 terest to remember that gray wolves use three calls in group 

 hunting: The rallying call is a howl which signals "game too 

 strong to manage alone." The hunting call, a higher pitched 

 howl vibrating on two notes, keeps the pack oriented to the 

 prey. The closing-in call, a combination of short bark and howl, 

 is a signal to attack the victim (Seton, 1953). 



It is easy to imagine that the roar of a lion, followed by a 

 few bites, could become (by classical conditioning) the sign of 

 a lion. Imitation of the roar, in the absence of the lion, would 

 be a step in the direction whereby signing becomes symboling. 



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