42 BELL SYSTEM TECHNICAL JOURNAL 



However, when he used six tones which were separated from each 

 other by a single tone interval, the separate components could not 

 be distinguished and a painful sensation was produced. The ob- 

 server was apparently faced with the situation that to make the ob- 

 served intensity ratios and phase differences correspond to a single 

 source would involve extremely large corrections in the observed 

 data. On the other hand, his power of tone resolution was insufficient 

 to separate the components and assign them to different sources. It 

 is not surprising, then, that the difficulty manifested itself by painful 

 sensations. While this illustration is taken from an extreme condi- 

 tion of laboratory experiment and may appear to have little bearing 

 on the every-day location of sounds, it is really significant because of 

 the manner in which it illustrates the importance of psychological 

 factors in all cases in which the sound waves are distorted. 



Resume 



In the foregoing discussion an attempt has been made to bring out 

 the main features involved in extending the theory of the binaural 

 location of pure tones to cover, qualitatively at least, the location 

 of complex sounds. It has virtually been assumed that the latter 

 involves three processes: first, the resolution of the sound into its 

 component tones; second, the independent (generally subsconscious) 

 location of each separate component; and third, the formation of a 

 conscious judgment of the position of the source based on the locations 

 of the individual images. The greatly increased amount of data 

 available when the sound is complex has quite different effects on the 

 final result according as the different images do or do not coincide. 

 If they do, the accuracy of location and the sense of certainty are 

 increased. If they do not, confusion arises, subconscious corrections 

 are called for, and the final result is likely to depend very consider- 

 ably on the psychological processes and individual prejudices of the 

 particular observer. 



