Human Brain's reaction to Scary Stuff

[Froge]

I'd go with height, blood, worms, and many-legged creatures as my main phobias. Not sure how that's relevant to the thread, but everyone is discussing them.

On-topic: Personally, I think doubt is the largest root of fear. Not all animals can comprehend uncertainty, or at least be in an "uncertain" state; somewhere along our evolutionary line we learned that there are things we're unsure of, such as who's hiding behind our backs, and that made us more cautious and thus more able to survive.

No irrational fears of boogie-men under the bed, or Kman hiding in your closet at night.

Why would you ever be scared of something like that?