For people working in technical fields (statistics, programming, etc.) it's important to devote time towards self-improvement. In theory, a continuously improving work force should also benefit the business, but the reward is often not immediate and hard to demonstrate to the management.
Thus, I find that it's much easier to have a boss that's sympathetic towards self-learning on the job rather than try to convince a skeptic.
During the interview, how to figure out whether the boss will be open to self-learning on the job (not just at home)? Asking point blank probably won't be effective, since no one would say "No, we do not support employees' learning and improvement."