I was having an argument with a friend the other day. It went vaguely like this,
Friend: "I'm not very disciplined. At some point I'm going to buckle down and train myself to be much more disciplined."
Me: "From experience and from what I know about humans, that's not going to work."
Friend: "Why? Motivation can come from within. If you can just train yourself like you're in the army, then you can become just as self disciplined as a soldier."
Me: "Yes, but the reason why people in the military are disciplined is because they have social incentives to be. In order to become disciplined, you need to create an environment for yourself that shapes your motivation. You can't just wake up one day and become a soldier."
Friend: "Sure, you might have to set up some environment like that. But once you've trained yourself, the discipline will stick, and you will be able to self motivate yourself from then on."
Me: "This theory would predict that people who were trained in the military would be much more productive three years after their service, compared to people who were never trained in the military. Do you agree?"
Friend: "Yes, I think that is likely."
Me: "I disagree. They might be slightly more productive but I'd predict it would be pretty similar."
So who is right?
I haven't been able to find direct research, but this seems like a classic instance where a debate can be settled by simply referencing a high quality experiment.