Canalizing Change

Psychobiological development, particularly with respect to the maturation of neural functions, has historically been characterized by a sequential decrease in plasticity across various functional levels. This chapter seeks to reconcile this traditional view with the growing body of knowledge on brain plasticity by examining the concept of canalization. It explores the contributions of Waddington’s chreode, Gottlieb’s probabilistic epigenesis, and Johnson’s interactive specialization to understand canalization as a developmental mechanism that allows for the stabilization of function while simultaneously preserving plasticity. Although the focus on canalization appears to contradict the notion of a flexible brain, studying development as canalized change allows for the identification of prerequisites for plasticity. This facilitates the analysis of differences in plasticity across various functional levels and reveals that, from a developmental perspective, constraints at one level can enable flexibility at another, supporting a multilevel pathway model. Finally, this chapter raises the question of how stability and plasticity are achieved at the level of individual neurons and explores the potential role of neuroepigenetic mechanisms as biomarkers of canalization and plasticity in the brain.