[M]an was created as a mature being, not a child. This is a fact of central importance. Humanistic psychology looks backward to a primitive past in order to explain man, whereas Biblical psychology looks neither to the child nor to a primitive past to explain man, but to a mature creation, Adam, and to God's purpose in man's creation. According to Jastrow,

What we may accept is the principle that the child is an authentic embodiment of the earliest, racially oldest, most persistent, truest to nature, depository of natural behavioristic psychology.

If man in his origin is a product of a long evolutionary past, man is then best understood in terms of the animal, the savage, and the child. However, since man was in his origin a mature creation, his psychology is best understood in terms of that fact. Man's sins and shortcomings represent not a lingering primitivism or a reversion to childhood but rather a deliberate revolt against maturity and the requirements of maturity. By ascribing to man, as humanistic psychologies do, a basic substratum of primitivism and racial childishness, this revolt against maturity is given an ideological justification; the studied and developed immaturity of man is encouraged and justified. If man is reminded rather that he was created in Adam into maturity and responsibility, his self-justification is shattered. It has become commonplace for persons seeking counselling to discuss, not their problem, but their childhood, their parents, and their environment in order to "explain" their present "situation," that is, their failure. The fact of a mature creation is one of the basic and most important facts of a Biblical psychology. It is a fact of incalculable importance.

R.J. Rushdoony, "Creationism and Psychology," Revolt Against Maturity, 1977