" 4. Differentiation—making the smallest possible sensory distinctions between movements—builds brain maps. Newborns, Feldenkrais observed, often make very large, poorly differentiated movements based on primitive reflexes, using many muscles at once, such as reflexively extending their entire arms. They also cannot discriminate among their fingers. As they mature, they learn to make smaller, more precise individual movements. But the movements do not become precise until the child can use awareness to discern very small differences among them. Differentiation, Feldenkrais would "

― Norman Doidge , The Brain's Way of Healing: Remarkable Discoveries and Recoveries from the Frontiers of Neuroplasticity