More or less human

There's a tendency amongst commentators, and especially Bible translators, to interpret "the heart" in the Old Testament as roughly equivalent to intellectual capacity or exercise; hence, "heart" is often translated in Proverbs as "understanding" or even "intelligence." However, a more literal rendering can allow for a more provocative reading, as in Proverbs 15:32.

He who ignores discipline rejects his soul,
but he who hears reproof acquires heart.

One might say that to reject discipline is to become less human; to embrace it is to become more so.