The researchers say that negative associations likely have such power in most people's minds because evolution prepared us to notice bad things more than good things. “If there’s a lion hiding in a bush, you’d better see it,” . “Whereas if there’s a tree of mangoes, it’s unfortunate if you don’t notice it, but it’s not as critical to your survival.
” Since each negative association has more weight in the brain, one must overcompensate with many positive links just to get back to neutral. The psychologists aren’t clear on why some people don’t make negative associations, but they are looking for genetic and social factors that predict it.

Unfortunately, other research shows that simply wanting to be less negative -- or less racist -- won't actually work. You have to do something about it. The best way to become less racist, say psychologists, is to spend time with the very people you're prejudiced against.

This reminds me of

"A Christian Spends 30 Days As A Muslim"