All that was needed in the figure was something which
would suggest the full picture to the mind. Indeed, it is probably true
that the full picture was not needed, even in the reader's
consciousness. Memory images are usually much simplified reproductions
of the perceptual facts. In writing we have a concrete expression of
this tendency of memory to lose its full reproductive form and to become
reduced to the point of the most meager contents for conscious thought.
The simplification of the written forms is attained very early, and is
seen even in the figures which are used by savage tribes. Thus, to
represent the number of an enemy's army, it is not necessary to draw
full figures of the forms of the enemy; it is enough if single straight
lines are drawn with some brief indication, perhaps at the beginning of
the series of lines, to show that these stand each for an individual
enemy. This simplification of the drawing leaves the written symbol with
very much larger possibilities of entering into new relations in the
mind of the reader. Instead, now, of being a specific drawing related to
a specific object, it invites by its simple character a number of
different interpretations. A straight line, for example, can represent
not only the number of an enemy's army but it can represent also the
number of sheep in a flock, or the number of tents in a village, or
anything else which is capable of enumeration. The use of a straight
line for these various purposes stimulates new mental developments. This
is shown by the fact that the development of the idea of the number
relation, as distinguished from the mass of possible relations in which
an object may stand, is greatly facilitated by this general written
symbol for numbers. The intimate relation between the development of
ideas on the one hand and the development of language on the other is
here very strikingly illustrated. The drawing becomes more useful
because it is associated with more elaborate ideas, while the ideas
develop because they find in the drawing a definite content which helps
to mark and give separate character to the idea.

As soon as the drawing began to lose its significance as a direct
perceptual reproduction of the object and took on new and broader
meanings through the associations which attached to it, the written form
became a symbol, rather than a direct appeal to visual memory. As a
symbol it stood for something which, in itself, it was not. The way