Progressive externalization

진화적으로 유의미한 기간동안 계속해서 안정적으로 주어지는 외부 자극이 있을 경우, 이 외부 자극이 주어질 것을 “가정하고” 발생/발달 과정을 코딩하는 것.

Enlarging the primate neocortex by adding rounds of cortical neurogenesis during evolution has the consequence of making postnatal development more protracted. Constructive learning makes the development of the neocortex increasingly sensitive to the environment. Since there’s a limit to how much genes can specify, or how large brains can become, at some time during evolution, making brains more complex demanded escaping this limit. The escape route came by finding a partner to hold part of the brain’s developmental program - probably relatively simple parts of the natural world early in evolution. Over time, the developmental program came to rely more and more on the world. The process of increasingly incorporating the world into the brain’s developmental program, a process we termed progressive externalization, is a way to make the brain more adaptable in an uncertain world.

The brain’s developmental program, then, is not simply contained in the genes. Rather, it is held implicitly in the interaction between genes and the world., —p55, Liars, lovers, and heroes