~ since skills are built from sub-skills, improvements can propagate

The important thing to appreciate here is that a direct new innovation in one particular capability can have far-reaching effects throughout the rest of your capability hierarchy. A change can propagate up through the capability hierarchy; higher-order capabilities that can utilize the initially changed capability can now reorganize to take special advantage of this change and of the intermediate higher-capability changes.

—— ❐ Augmenting Human Intellect﹕ A Conceptual Framework