Environment vs. Biology

Today I met someone from a very different background from myself. He was what you could call a little rough around the edges. And by rough I mean course, rude, and drunk. But through that exterior there shone bright, albeit brief, moments of a responsible, thoughtful, and respectful person. Not to say there were enough of these moments that I would want to spend any more time with him than was absolutely necessary.
It makes me wonder, is this person merely a product of his environment and the brief moments of politeness are flashes of what great potential are contained inside? Or is it simply a miracle that there are spots of light at all? It's the age old question, what shapes a person? Is our environment responsible or are we predisposed to be a certain way?
There is no way it's that simple. From what I have seen and experienced there is some predisposition that is then covered by experience. Anyone who has spent any time with newborn babies will know that they all do not act the same way. Some are docile and quiet, others noisy and active, and everywhere in between. Score 1 for biology. Also, quite often you hear stories of people with less than stellar backgrounds rising above their upbringings to go on to greatness, be it as a public success or as a person of moral integrity. On the flip side, people brought up with many advantages sometimes end up entirely bereft of character and responsibility. Score 2 for biology.
But then I look at my life experience. Although the change I have seen in myself over the past 7 years is far less drastic than going from heathen to aristocrat, or charlatan to pillar of morality, I do see a change in my actions, attitude, goals, and tastes. Would these changes have taken place had I not moved out of my parents house? Would I be the same person today if I had not moved to the east coast? The answer is quite clearly, no. My environment has changed me if not entirely, at least drastically in the finer points.
Now I am lead to ask the question, had I been brought up in the same place and under the same circumstances as my new acquaintance, would I be so rough on the outside with only small points of light pointing to my true self? Surely the question is unanswerable and of course I am quick to say "Of course I would have the same moral fortitude regardless of upbringing," but if I am really being honest with myself, I know that cannot be the case.
Man is born with an innate sense of caring for fellow man, but only to the point that it does not lead to the destruction of oneself. Given the choice between looking out for yourself or another, the innate sense will choose the self. Only a being who has had their sense of selflessness cultivated and has been shown by example such actions of giving will choose the well being of another over that of themselves. Score a big one for environment.
I leave you with this example. Everyone in this country is taught at an early age that 3 x 3 = 9. But if a person is never taught the multiplication tables, and even more than that, not ever taught to count, they will never know that 3 x 3 = 9. It doesn't make that equation any less true, nor does it mean that that person is incapable of understanding the concept, they simple lack the instruction to understand it. Yes, some people would figure it out on their own (how else would we know this unless someone figured it out), but far fewer people would know it if each person had to start from scratch to uncover it.
So perhaps the man I met today never learned math either.