BIOPSYCHOLOGICAL 597 



monkeys he could really train were those who could pay attention ; 

 and that these were not by any means common. Here there is a 

 point at once of interest and of practical difficulty for experimenters, 

 and one suggestive towards evolutionary interpretation as well. 



Mrs. Learned made a careful record in musical notation of all the 

 sounds habitually uttered by the two chimpanzees already men- 

 tioned. They fall into four groups, according as they were made 

 while waiting for food, while eating, when in company with persons, 

 or when two chimpanzees were together. Seventeen of the sounds 

 begin with gutturals, like gho in greeting friends; four begin with 

 an aspirate, like ho-oh in alarm; five begin with nasals and labials, 

 like ngak — a food-word; five begin with vowels, like ah-oh-ah — a 

 half -scream of apprehension. There is a much larger repertory of 

 vocalisations than was suspected; and these might form the basis 

 of a language if the chimpanzees began to imitate sounds persistently, 

 as parrots do. But there is almost no trace of this. So Mrs. Learned 

 concludes: "Although the young chimpanzee uses significant 

 sounds in considerable number and variety, it does not. in the 

 ordinary and proper meaning of the term, speak." 



As words seem to have played a very important part in the 

 evolution of human intelligence, we make no apology for lingering 

 over the question : Have chimpanzees a language ? What is said here 

 will apply to other gifted animals like dogs. In the first place 

 chimpanzees have the same vocal instruments as man has; there is 

 a close resemblance in the larynx and in the vocal cords. In the 

 second place they have "a good voice" and a considerable gamut 

 of sounds, which are used consistently, e.g. as expressions of joy or 

 of anger, or in particular situations, such as the announcement of 

 dinner. 



But the chimpanzee has not been known to imitate a new sound 

 as parrots do; and this, along with some expression of a judgment, 

 seems to be the essence of language. Parrots have made the first 

 step, for many are quick to pick up a new sound; but even the 

 cleverest parrot is not known to make a sentence expressive of its 

 own judgment. That it may repeat a sentence, often jerking it out 

 with uncanny appropriateness, is well known, and may sometimes 

 illustrate "association learning"; but the parrot's sentences are 

 simply, so to speak, very long, much broken up words. 



Various attempts have been made to teach chimpanzees to speak, 

 but without success; though it is very interesting that Yerkes's 

 Chim occasionally mumbled a little when people were talking in 

 his presence, that he became interested in listening, and that he 

 sometimes answered back in an appropriate way to certain note- 

 worthy sounds. One of the methods of instruction was to arrange for 

 the mechanical delivery of pieces of banana on the table of Chim's 

 observation-room, and to utter the sound "ba, ba!" as a signal for 



