In response to Mr. Skeptic:
From my point of view, it seems that as a civilization, we might actually be moving in the opposite direction. As our society becomes more and more self-sufficient, interconnected and complex, we are also becoming less barbaric. Incidences of racism and hate crimes seems to fall as countries become more civilized and developed. Dodgeball has been eliminated from gym classes because our society empathizes with failure to an unprecedented level.
Perhaps it's our collective removal from life threatening situations that leaves room for magnanimity and altruism. Technology works to provide humans with comfort and security. It was the rise of agriculture that spawned complex thought in humans; we were no longer forced to concern ourselves with the acquisition of food on a day to day basis, and could therefore put more time into intellectual endeavors. Instead of competing with each other, we began to work together because we were intelligent enough to recognize that life is easier when "we all get along".
Sure, we still have wars. We still have genocide. Its 2009 and there are horrible things that people still do to each other every day, but a majority of the population recognizes these actions as "wrong". I guess what I'm trying to say is that maybe with increased intelligence comes a rise in understanding and peace.
In response to Moontanman:
Resources, a habitable environment, a relatively stable launching point, a means of catching overflow populations? I definitely see where you're coming from, but think about our own progress; as we begin to explore the space outside of our own planet, we are constantly searching for bodies that parallel our earth. We are reaching a critical mass both in population, and use of resources. For humans, "artificial space habitats" that can house entire societies are just impractical. Wouldn't it be just as unrealistic for an alien race?