In the late nineteenth century and through much of the twentieth century, t
he notion of the early developmental autonomy of motor behavior pervaded be
havioral embryology and the developmental psychology of infant behavior. In
the midst of this predeterministic climate of opinion concerning motor dev
elopment, Myrtle McGraw briefly and tentatively broached the probabilistic
epigenetic notion of a bidirectional or reciprocal relationship between str
uctural maturation and function, whereby structural maturation of the nervo
us system is influenced by functional activity as well as the other way aro
und. Myrtle McGraw thus anticipated our current understanding of the role o
f experience in the cortical and motor maturation of infants in the first y
ear of postnatal Life. It is all the more remarkable that she made this con
tribution when the theoretical climate of opinion was epitomized by predete
rministic epigenetic thinking. In the same vein, McGraw's second unrecogniz
ed contribution is her clear formulation of a suitably flexible critical pe
riod concept in 1935, one that is consonant with our current understanding.
(C) 1998 Academic Press.