The Individual as an Information Processing System 303 



1) Boundary. This may be the limits of the sense organ of a 

 cell or animal or the mechanisms of a group or society which 

 receive information from outside the system. 



2) Input Transducer. A transducer changes energy from one 

 form to another. The sense organ of an animal transduces patterned 

 energic inputs to nerve impulses. There are analogs at the society 

 level in the translaters that receive and recode information from 

 outside the society. 



3) Internal Transducer. This subsystem receives and passes 

 on information from within the system, as the input transducer 

 does from without. In an animal there is the system of internal 

 sense organs and chemical sensitivities which activate control 

 mechanisms. There are analogs at the group and society levels. 



4) Channel and Net. The channel is the route — neuron, wire, 

 air or ether — over which a message is sent from a transmitter to 

 one or more receivers. In the individual the sensory nerves are 

 channels over which the input is transmitted to the central nervous 

 system. Channels may intersect at points called nodes and may 

 be interconnected to form a net. The nervous system of individuals 

 is an information processing net. The blood and lymph of the 

 individual also act as information carrying channels as well as 

 energy distributors. There are two distinct common uses of the 

 word "channel."' The more restricted meaning includes only the 

 flow route for the information, without intervening subsystems 

 of any other sort (such as transducers, decoders, or encoders). 

 The other, broader meaning includes such components together 

 with the intervening flow routes. "Channel" is employed in both 

 these senses in electronics and little confusion appears to result. 

 We follow the second usage. 



5) Decoder. The decoder alters input information into a code 

 or language which can be transmitted and "interpreted" inside 

 the systein. 



6) Learner. This subsystem establishes a reliable and enduring 

 association between certain information inputs and other infor- 

 mation from outside or inside the system. Thereafter, the system 

 will make an altered output to an input which previously elicited 



