312 Information Storage and Neural Control 



5) Approximation, which is an output mechanism whereby a less 

 precise or less accurate response is given because there is no time to 

 be precise; 



6) Multiple channels, which parallel transmission subsystems that 

 can do comparable tasks at tiie same time and consequently to- 

 gether can handle more information than a single channel can 

 transmit alone; 



6a) Decentralization, which is a special case of this; and, finally 

 there is 



7) Escape, which is leaving a situation entirely or taking any 

 other steps that effectively cut off the flow of information. 



Thus we have searched for quantitative similarities and differ- 

 ences among living systems at all levels in the way they react to in- 

 formation input overload, and have given special attention to a) 

 performance characteristics of a system as an information processing 

 channel; and b) associated adjustment processes used to relieve 

 stress on the information processing subsystem and maintain per- 

 formance. 



Our original intention in approaching the problem of over- 

 loading living systems with information was to study a single 

 variable — the input-output rate relationship — postulating a formal 

 identity of this function in channels at all levels of living systems. 

 But this proposition turned out to involve numerous others about 

 many variables representing other aspects of systems. The whole 

 problem ramified in a fascinating way. 



We built apparatuses and designed procedures which we hoped 

 would provide stable conditions for collecting performance data 

 from the systems we selected for study, attempting to hold con- 

 stant as many of the variables not under investigation as possible. 

 We were not concerned primarily with obtaining the maximum 

 possible transmission rates from our systems, but rather attempted 

 to create a stable situation in which we could test our overload 

 proposition and be sure we knew when overload occurred. Later 

 we could study as independent variables those functions which 

 change a given system's maximum channel capacity. 



Since information bits per second had been used by others in 

 researches at all five levels, we believed this to be a suitable measure 



