On the one hand, it is human nature to be suspicious of anything that seems different to yourself.
But in my experience, I don't think that stands up to developing human rationality unless it is culturally encouraged. To give my example here and the limitations of my views- I live in an area that has little racial tension. It's not entirely white by a long way and there are significant minority communities but you would certainly call it a predominantly white area. Immigration is moderate, in part present because there is a major hospital nearby that trains and uses foreign labour (I teach English to a bunch of the nurses from Spain or Africa)
So, it is not an inner city type of area where such issues have traditionally existed so I have never grown up in a background of racial discord from my friends or relatives, so I am in no position at all to make a comment compared to someone who has grown up in an area of such tension.
But for my part, I can very comfortably say that the idea of racism or other sorts of strong discrimination never, ever occurred to me as I was growing up, and nor was it any part of thinking amongst my friends. The idea that I would treat someone differently due to, say, the colour of their skin just was not there. I am not trying to show off here; it genuinely never occurred to me think in those terms. It was something that I had to learn about via school or hearing about it in other places, and it always struck me as a strange thing, and the few friends I have who do occasionally say the odd unacceptable thing are very much in a minority and basically know it is wrong; it;s a secret shame of theirs.
Whether, left to our own natural devices, we would have caused subconscious or unintended discrimination is another and more complex area. But on a basic level, I do not think discrimination is in any way endemic to the human experience. It really only occurs in cultures that reinforce it- which is to say, rather a lot of cultures, but that being so I am very confident it can be largely eliminated over time.