One of the older, best-known, and influential formulations of the concept is Socrates' famous dictum "I know only that I know nothing," which is generally held to mean that true wisdom consists in knowing the limits of your knowledge. There are echoes of that still alive in what you're talking about. The idea is that an excess of learning can lead to intellectual arrogance, and that much of what we think of as knowledge serves, in effect, as a distraction away from true wisdom. The simpler, less educated person can sometimes surprise or impress us with their superior wisdom.
There's a similar message, also of ancient origin, in Ecclesiastes, for instance in 1:17, "In much wisdom is much grief. And he that increases knowledge increases sorrow." (Thanks to Rushi for this cite.)
It's worth being aware, however, that there's often also a whiff of patronization in this attitude--part of a general romanticizing of the "have-nots" by the "haves."