Assume there are aliens, if they exist would they be a pro-social species, and would those pro-social attitudes extend to life on this planet?
I am assuming no species would develop the level of technical sophistication necessary for interstellar travel unless they had pro-social tendencies. Those devices cannot be built in isolation, as far as I know. You need millions of organisms working together as a society for long periods of time to achieve that goal. You have to respect the wants/needs of other people in your civilization to be advanced and big enough to eventually develop interstellar travel.
But social insects are pro-social, however they won’t hesitate to attack an outsider. And humans are no different we are pretty adept at shutting off our pro-social attitudes at the edges of the society we identify with and depend on for protection.
According to computer models, the best survival model is one where organisms cooperate, unless and until one becomes a threat or a welcher (these work better than everyone for himself models or models where people are too nice that they get taken advantage of). Then that organism who is cheating or a threat is punished and/or shunned. Wouldn’t that rule apply across the universe? Would most technologically advanced species have developed a pro-social attitude, but they turn it off when individuals threaten the collective or are not important to it?
On another note, I’ve heard humans are more egalitarian than some other apes, and it could be because we evolved to throw stones. As a result of this, no alpha male could bully all the other males in a small tribe. If one did, the others would gang up and beat him to death. This led to the selection of egalitarian traits in hunter gatherer societies. With the advent of agriculture the opposite happened and bullies could roam free again since they controlled the military and police. So I have no idea if an alien species had this in their background. What if humans had evolved from babboons (who are generally assholes) rather than going through a phase of egalitarian hunter-gatherers in our history?
Wouldn’t a species capable of interstellar travel also be capable of advanced neuroscience, and as a result change their own brains to become whatever is productive based on their goals? It is obvious that we as humans are still relying on failed cognitive programming that worked in our past environment but doesn’t work now (xenophobia, eating unhealthy diets, not taking risks like climate change seriously while freaking out over spiders, being easily distracted by celebrities and wedge issues, religious superstition, etc).
Would an alien race be benefited by programming themselves to be capable of extreme evil in the face of outsiders? Or would there be more benefits from programming pro-social tendencies into their brains? If an alien species could program and reprogram their minds, what kind of ethics and morals would they pick and how would that relate to contact with the humans?
So aside from evolution affecting possible alien behavior, there is also the reprogramming of cognition by aliens. Any species advanced enough to travel across space would be advanced enough to rewire their own brains (or whatever they have). Are there any reasonable benefits to aliens intentionally making themselves hostile to other intelligent life?
On the subject of aliens being hostile, I can’t really see many motives. What do we have that they want? Would they keep us as slaves? Machines are more productive than slaves and aliens have nothing to gain from enslaving us. Our natural resources are dwarfed by the natural resources a truly advanced civilization could find in the galaxy not to mention make themselves out of fusion. Any hyper advanced society has probably perfected fusion and by proxy alchemy, the ability to make any element out of (abundant) hydrogen. So our natural resources mean nothing.
If they find our atmosphere hospitable (which would be a major coincidence) they would probably know how to terraform a different planet.
The only realistic reason I could see them being hostile to humans is if aliens wanted to study biology and preserve biodiversity, and saw humans as a threat to the biological life on this planet. Humans are causing a 6th extinction right now, so if an alien race was interested in preserving biodiversity, I could see them killing us all. Aside from that I can’t see any real reason aliens would be dicks.