Such myths are almost universal, and even survive in our modern belief that a college degree confers abilities on the one who holds it. As for such objects in Greek mythology, it might be better to think of a SUBSTANCE rather than an object. On the rare occasion when a favored human was allowed the use of NEKTAR (it was said to be "distilled in the breast" of such a person by one of the gods), its effect was different than when used by the gods themselves (whom it rendered "athanatos" or deathless). Such a person temporarily attained the ultimate of whatever his natural gift was, and could not be outdone by any other mortal in said endeavor for so long as the infusion of nektar lasted. A nektar-infused warrior was unstoppable, a poet or sculptor could produce "divine" works and athletes could not be bested in competition while under its influence. There are, of course, many "magical items" given to heroes to accomplish the object of their adventure, but these do not generally confer abilities to the user as such. Finally, one of the "Big Three" philosophers (Socrates? I forget) actually posited a pretty intuitive substance-based theory of ability, not so far off the idea of DNA. He said that people should be told that their souls were compounded of certain metals, and that those in whom gold predominated were suited to be the leaders in government, military, commerce et cetera. That do it for ya?