202 Part II Psychodynamic Theories
In similar fashion, the ego follows the path of epigenetic development, with
each stage developing at its proper time. One stage emerges from and is built
upon a previous stage, but it does not replace that earlier stage. This epigenetic
development is analogous to the physical development of children, who crawl
before they walk, walk before they run, and run before they jump. When children
are still crawling, they are developing the potential to walk, run, and jump; and
after they are mature enough to jump, they still retain their ability to run, walk,
and crawl. Erikson (1968) described the epigenetic principle by saying that “any-
thing that grows has a ground plan, and that out of this ground plan the parts
arise, each part having its time of special ascendancy, until all parts have arisen
to form a functioning whole” (p. 92). More succinctly, “Epigenesis means that
one characteristic develops on top of another in space and time” (Evans, 1967,
pp. 21–22).
The epigenetic principle is illustrated in Figure 7.1, which depicts the first
three Eriksonian stages. The sequence of stages (1, 2, 3) and the development of
their component parts (A, B, C) are shown in the heavily lined boxes along the
diagonal. Figure 7.1 shows that each part exists before its critical time (at least as
biological potential), emerges at its proper time, and finally, continues to develop
during subsequent stages. For example, component part B of Stage 2 (early child-
hood) exists during Stage 1 (infancy) as shown in Box 1B. Part B reaches its full
ascendance during Stage 2 (Box 2B), but continues into Stage 3 (Box 3B). Similarly,
all components of Stage 3 exist during Stages 1 and 2, reach full development
during Stage 3, and continue throughout all later stages (Erikson, 1982).Children crawl before they walk, walk before they run, and run before they jump.
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