SOME REMARKS ON SYSTEMS 



255 



acuity, but also upon the capacity of the 

 individual to comprehend and to retain, i.e., 

 upon the spans we have discussed above. 



Problems in auditory communications do 

 not cease with these major ones, however. 

 Poor intelligibility of electrically transmitted 

 speech (without respect to ambient noise) 

 may lead to misunderstanding. Another 

 grows from American habits of use of the 

 telephone. Circuits which may be called 

 upon for instantaneous use may be cluttered 

 with idle chatter. The problem of circuit 

 discipline was nearing solution toward the 

 end of the recent war, but was not 

 universally solved. Telephone circuits are 

 often crowded circuits. 



Other diflficulties arise in special circum- 

 stances. An instance has been reported in 

 which the sounds of loud auditory com- 

 munications proved objectionable, if not de- 

 moralizing, to members of the crew of a 

 submarine after a severe depth-charging. 

 Doubtless there were other such cases. 



These difficulties may appear as relatively 

 minor. They must, however, be recognized 

 and, if possible, circumvented. The rapidity 

 of auditory communication, and the sim- 

 plicity of the apparatus required, ensure 

 that audition will remain the normal and 

 most important method of transient com- 

 munication. Nevertheless, visual commun- 

 ication may prove to be a useful supplement 

 to voice in reducing the hazards created by 

 the difficulties we have noted, since it is 

 in those areas where auditory communica- 

 tion is weak that visual communication may 

 possess special advantages. It must be rec- 

 ognized, however, that these advantages are 

 not yet fully realizable. 



Visual systems have remained largely un- 

 developed for transient communication, 

 whether interior or exterior. The develop- 

 ment of the telegraph, telephone, and radio 

 has aborted their development. Visual 

 communications are still, to some extent, 

 emploj^ed in ship to ship communication; 

 the signal flag and blinker remain. Even 

 here, however, the}'- have been found useful 



only in the absence of efficient auditory 

 systems, where distance or inconvenience 

 makes direct communication by TBS or code 

 inconvenient or impossible. Recent de- 

 velopments in electronics have served still 

 further to reduce the role of vision in com- 

 munication. During World War II, inten- 

 sive research was performed on auditory 

 communication — on the intelligibility of 

 sounds, on microphones and other equip- 

 ment, on telephone circuits, on radio teleg- 

 raphy, and on code signalling. However, 

 practically none was done on the still prim- 

 itive visual systems, such as blinker- 

 signalling and semaphore, except to obtain 

 data on visibihty ranges. Neglect of the 

 possibilities of visual systems for interior 

 communications is also evident. 



Visual communication would seem, po- 

 tentially or actually, to have the following 

 advantages. First, it is fully resistant to 

 masldng by noise, and is easily rendered 

 equally resistant to interference by other 

 type of competition. Second, the visual sig- 

 nals employed may be made to persist 

 through a period of time great enough so 

 that the immediate memory span and the 

 span of apprehension of the receiver are 

 not exceeded, as often happens in hearing. 

 Third, a wide variety of information may 

 be simultaneously transmitted. Fourth, sev- 

 eral individuals may simultaneously receive 

 the message, which is impossible with the 

 telephone. Fifth, more rapid, more ac- 

 curate methods of acknowledgement are 

 made possible. Sixth, visual communica- 

 tion designed for specific purposes is not 

 apt to be subject to circuit ja mm ing. 



The difficulties of visual communication 

 are not to be overlooked, and stem primarily 

 from their lack of flexibility, that is, from 

 the limitation of the number and variety of 

 the messages which may be transmitted 

 without the existence of some complex and 

 bulky system, such as the teletj^pe, and 

 without extremely long training. A com- 

 pletely flexible visual communication system 

 that does not utilize the printed word would 



