The Individual as an Information Processing System 305 



ferences, the quantitative study of tiiese requires the use of com- 

 parable measures at different levels, and the units of the natural 

 sciences seem best suited, though, of course, all sorts of phenoinena 

 cannot yet be expressed in them. 



THE ROUTE OF INFORMATION FLOW 



Each one of a person's subsystems may participate in the 

 preparation of the output. Input of appropriate kind and strength 

 crosses the individual boundary and is transduced into the proper 

 form for nervous transmission. If a language or code is involved, 

 it is translated by the decoder and classified by the perceiver in 

 terms of a perceptual schema which represents the world as the 

 individual has experienced it. Reference may be made to stored 

 memories. There may be some recoding or other preparation of 

 all or part of the input for storage in the memory. On the output 

 side, a decision is made from among the alternate possible outputs; 

 encoding for external transmission is carried on, and the nervous 

 message is transduced into physical response, through either the 

 speech mechanism or other musculature. There is a large literature 

 on each of these functions and it is impossible to do more than 

 give a brief review of some of the material on some of the sub- 

 systems. Not all input, of course, is channeled through all the 

 subsystems. A reflex response to an input may involve only a 

 small number of subsystems. Complex decisions may make use 

 of the whole range of individual subsystems. 



Throughout the system there is a continual and cumulative 

 loss of information. One important aspect of the response of 

 biological systems, as both Gerard (2) and Piatt (3) have recog- 

 nized, is amplification. That is, the energy in the signal is very 

 small compared to the energy in the response. At the same time 

 there is a loss of dimensionality from input to output in all am- 

 plifiers, which must select in order to amplify, since they have 

 limited power available. There is distortion of information at 

 each boundary that is crossed, and furthermore, noise alters the 

 signal. The sense organ reacts only to part of the information 

 present in the environment. The perceiver screens and organizes 

 the input further, and in the process ignores that part of it which 



