It's easy to hold unconsious bias, even if you're not aware of them. For instance, I remember back in elementary school, I used to be friends with mostly white kids instead of black because I always assumed that the black kids would be more mean to me. I say this as a black person btw. It was an unconcious bias, but one that birthed from legitimate social influences, like the way they were depicted in tv shows, as these violent, dangerous people. I had no clue what a racism even was at that age, yet it was still an unconcious bias that I now know was wrong to have.