The Individual as an Information Processing System 311 



We have been interested in one aspect of channel capacity 

 which can be studied at five levels of living systems. What happens 

 at each level when a channel is overloaded? 



INFORMATION INPUT OVERLOAD 



From a review of the literature we were able to draw a curve 

 which appeared to apply at each level. The general shape of 

 this performance curve shows the output (in bits per second) rising 

 as a more or less linear function of input until channel capacity 

 is reached, then leveling off and finally decreasing in the con- 

 fusional state. This cross-level generality appeared fairly con- 

 vincingly in the empirical work of others, even though it was not 

 recognized as such by them. At the same time, we also found 

 suggestions as to hierarchical differences among the levels. The 

 overall impression of the findings is that channel capacity decreases 

 from cells to organs, to individuals, to groups, to social organi- 

 zations. Processes of adjustment appear to be comparable at 

 different levels. 



We have hypothesized that there are limited numbers of such 

 adjustment processes which behaving systems can enlist as stresses 

 on them increase. The following adjustment processes, or mech- 

 anisms of defense, seein to be used by living systems against the 

 stresses of information input overload. Not all living systems have 

 all these inechanisms. The smaller systems, like neurons, appear 

 to have fewer than the larger systems, like societies, which not 

 only have all of them but also have complicated variations of 

 them. These appear to be the fundamental mechanisms, but this 

 may not be an exhaustive list: 



1 ) Omission, which is simply not processing information whenever 

 there is an extreme of overload; 



2) Error, which is processing incorrectly, then not making the 

 necessary adjustment; 



3) Queuifig, which is delaying responses during peak load periods 

 and then catching up during lulls; 



4) Filtering, which is systematic omission of certain categories 

 of information, according to soine priority scheme; 



