Comment by keeda

You're right actually, what I really meant to say is a "higher-level skill" rather than a "higher skill-level." Higher-level skills don't necessarily mean a more difficult skill, they're usually just at a higher level of abstraction.

Specifically, the 3 dimensions along with new jobs required new skills were: a) cognitive, b) technical or c) social skills. I guess tending to a machine was a mix of a) and b), because even if the controls were straightforward, it probably required some understanding of the underlying mechanisms.