“The brain becomes used to thinking in a certain way, it works in a groove, and when set in action, slides along the familiar, well-worn path; but when once it is lifted out of the groove, it is astonishing how easily it may be directed. At first it will have a tendency to return to its old manner of working by means of one mechanical unintelligent operation, but the groove soon fills, and although thereafter we may be able to use the old path if we choose, we are no longer bound to it.”
(Taken from “Man’s Supreme Inheritance” – p63)