What Is Memory that It May Have Hindsight and Foresight as well? - Understanding Understanding: Essays on Cybernetics and Cognition - page 110

drawing of a network representing a single memory unit or a “mnemon” as
he calls it. 16 Although Eccles' “The Cerebellum as a Neural Machine” 17
abounds with examples of such networks, they exhibit many more functions
than needed at this moment and thus I cannot consider them to be
“minimal” in this context.
Figure 2 reproduces Young's drawing of the organization of such a single
memory unit. He describes its general features as follows:
“. . . each unit consists of a classifying neuron that responds to the occur-
rence of some particular type of external event that is likely to be relevant
to the life of the species. The resulting impulse may initially activate either
two or more channels by branching of the axon. More than one line of
conduct is therefore possible. The mnemon includes other cells whose
metabolism is so triggered as to alter the probable future use of the chan-
nels on receipt of signals indicating the consequences of the actions that
were taken after the classifying cell had first been stimulated.”
From this it is easily seen that Young's mnemon indeed incorporates
minimally the two principles mentioned earlier. The principle of “selection”
or of “search for meaning” of a particular stimulus is incorporated by the
choice of pathways that lead to different actions. What that stimulus
“means” becomes clear to the animal of course, only after a test. “Attack”
may under certain stimulus conditions mean “Pain”, under others “Plea-
sure”. Note here the important point that neither pain nor pleasure are
objective states of the external universe. They are states that are generated
purely within the animal, they are “self-states” or—to use terminology of
physics—“Eigen-States” of the organism which permit it to refer each
incoming signal to its own self, i.e., to establish self-reference with respect
to the outside world.
With this observation, the second principle of inseparability of informa-
tion and its utilization falls smoothly into place, for this system checks the
incoming information as to its usefulness by comparison with its eigen-
states where upon it initiates the appropriate actions.
With regard to the functional organization of this memory element I wish
to make two points that will later become important in the synthesis of
a cognitive element. For this purpose, I have redrawn Young's anatom-
ical schema in order to let the relations of the various functions become
more transparent, rather than the anatomical ones. Figure 3 represents
an information flow diagram that is functionally equivalent to mnemon
of Figure 2. Again a classifying cell (cl.c.) allows for two alternate actions
that are initiated in the memory and motor cell complexes (A) or (B).
Young's collaterals pick up information of the action state from the
thick axon of the motoneurons (A) (B) and feed it to comparators (A + )
(A - ) or (B + ) (B - ) which evaluate the action states by comparing them
with the information of resulting eigen-states, either desired (+) or else
undesired (-).
The two points I wished to make earlier are now as follows: