38 Henry Quastler 



make sure that the system's performance is hmited informationally, and not 

 by difficulties of sensing inputs or generating outputs. 



It is possible to vary the informational challenge in a number of modes; 

 e.g. one can vary the number of sources of information, or the amount of 

 information per source. Challenging in various modes reveals whether or not 

 there exist several modes of limitation. It seems that the informational perfor- 

 mance wliich a system can produce in single tasks may be limited by the follow- 

 ing factors, singly or in conjunction : 



(1) the amount of information which can be processed effectively in a 

 single task, 



(2) the number of independent information-carrying components which 

 can be involved in a single act of infomiation-processing, 



(3) the informational contribution from each independent component, 



(4) all information-carrying components must be assembled within a 

 certain length of time ; 



(5) in addition, there seem to be two general limitations on time rates: 

 there is a minimum time for each act of information processing, and 



(6) the over-all rate of information-processing is limited (only this last 

 limitation has the character of a channel capacity). 



This list of limitations is based on psychological experiments (14) but is believed 

 to apply to all types of systems. 



Multi-part Systems — The informational system analysis is not restricted 

 to two-part systems. A system of three components can be represented as a 

 three-node network with a connecting channel: 



Fig. 7. A simple three-node network 



Again, it is merely a matter of convenience which node, or set of nodes, one 

 treats as the input, or independent variate. 



The treatment can be extended to any number of components. Thus, a 

 nine-node network is equivalent to one man receiving infomiation from eight 

 sources, or feeding information into eight sinks; or, to four men watching 

 two sources, communicating with each other, and feeding information into 

 three sinks; to a sentence of nine words; to a decision based upon eight factors. 



The more parts there are to a system, the more difficult becomes the infor- 

 mational analysis (15, 16). This is territory that has been but recently opened, 

 and we are still largely concerned with the formulation and highly tentative 

 application of concepts. It will be helpful to consider a parallel effort, namely, 

 the study of organization by game theory (17). One result of this study is that 

 each time a new player is added, the organization (the 'game') acquires a new 

 qualitative feature. One-person games deal with problems of maximum; 

 the addition of a second person introduces competition; of a third person, 

 coalition; of a fourth person, an asymmetric role of one player in relation to 

 the group of the other three, von Neumann (17) points out that it is at this 

 junction that the most remarkable problems begin to appear; also at this junction, 



