Settling the Nature vs Nurture debate?

In about a month, Colin will officially be a teenager. Eep! My own age doesn’t make me feel old, but watching my kids turn into actual people sure does.
As the boys get older, they become more and more unique – there are obvious genetic similarities, and they have some wonderful things in common, but they are clearly very different people, with different senses of humour, different ambitions, different philosophies, and so on.
I realize that this observation is not a revelation.
In the past few months, both boys have started talking about their future plans, and while the sudden interest in their future selves is shared, their visions reveal just how different they are. Colin’s plans are relatively short-term: he plans to visit several important theme parks over the next decade, perhaps even taking time off between college and university to tour the American parks. Beyond that, his plans are pretty vague.
Robert, on the other hand, has decided that he will (a) go to university so he can get a better-paying job, (b) live at home as long as possible because it’s cheaper, (c) get a small apartment when he does move out, to save money, (d) get a job that pays at least “thirty bucks an hour,” and (e) move to California.
Colin’s plans strike me as what one might expect from an almost-teenager. Robert’s plans, meanwhile, strike me as what one might expect from a survivor of the Great Depression.