I'm not saying that IQ and work ethic are linked, but rather that both are things that are to various degrees outside your control: https://www.scientificamerican.com/article/to-predict-succes.... Whether it's biological factors (e.g. there are measurable differences in the brains of violent offenders), environmental factors (lead), or nurture, by the time someone has reached the age of moral culpability, I'm not sure how much control they have over what we call "work ethic" or "self discipline."