It seems likely that kids and some adults will always have an irrational fear of the dark, since thousands of years ago nocturnal tigers used to eat our ancesto

It seems likely that kids and some adults will always have an irrational fear of the dark, since thousands of years ago nocturnal tigers used to eat our ancestors. The light/dark association is probably baked into our DNA due to this selective pressure; it's an unfortunate coincidence that similar words can be used to describe skin tone.