RATING TRANSMISSION PERFORMANCE 117 



performance of a telephone circuit could be limited to the functioning of 

 the circuit itself. In line with this, there has been some tendency to 

 confine such considerations to relations between the sounds reproduced 

 by the telephone circuit and the sounds impressed upon it. The per- 

 formances of the talker and listener, however, are materially affected in 

 certain important respects by the telephone circuit, and determinations 

 of the relative merits of the transmission performances of different 

 telephone circuits, must therefore go farther than the performances of 

 the circuits themselves and take account of the combined action of the 

 talker, circuit and listener. 



Characteristics of Conversation 



In view of this reaction of the telephone circuit on the talker and 

 listener, attention is directed to the pertinent characteristics of their 

 performances in both face-to-face and telephone conversations. 



Direct Conversation 



In direct or face-to-face conversations both the talker and listener 

 more or less subconsciously adjust their actions in many respects to 

 each other and to their circumstances. The loudness of talking is 

 placed initially at a level which experience has shown to be suitable for 

 the conditions and for the particular listener. If the listener indicates 

 verbally or by his expression that he is understanding easily or with 

 difficulty, some further adjustment may be made in the loudness of 

 talking. Since the talker judges his own talking level largely by the 

 loudness with which he hears his own voice, this level will be a function 

 of the amount of reverberation in the place in which he is talking. 

 Apparently for a wide variation of loudness in the customary talking 

 range, the speaker is not in general conscious of the amount of energy 

 which he is expending. Noise at the place of conversation also plays a 

 part in determining the talking levels since it makes louder talking 

 necessary in order to permit a given degree of understanding on the part 

 of the listener. 



Along with an adjustment in talking level, the talker may improve 

 his enunciation if difficulty of understanding is expected or indicated 

 by the listener. There may also be a change in the manner of express- 

 ing the ideas in avoiding words which experience has shown are difficult 

 to understand and an idea may be stated in more than one way in order 

 to insure its comprehension. Other adjustments on the part of the 

 talker may be determined by his opinion of the mental acuity of the 

 listener, by the familiarity of the listener with the matter under dis- 

 cussion and by the interest in it. These factors affect the way of ex- 



