Research on child development outlines expected progress in our children. Skills are learned in succession, with each set of skills building upon the previous.
Lately, I’ve been thinking of these developments as “levels”, akin to the kind you’d experience in a video game. If you take Super Mario Brothers, for example, your goal on each level is to have little Mario run quickly, pick up some coins along the way, avoid falling off cliffs, and defeat the “boss” at the end. The first few times you play any level, it is very difficult to complete, and Mario returns to the beginning many times before succeeding. Once he finally beats the big boss, you “level up”.
Suddenly you are at square one again, using the skills you’ve obtained on, now up against even greater challenges on level two.