I see that there’s not much about horror (psychology of, but only just now had a quick look, i’m going to bed) on the internet other than to do with films/entertainment.
If I go to the dictionary definition it tells me “.. an intense feeling of fear, shock, or disgust”.
My little brain’s telling me that sometimes horror might be used to describe a state of mind, or internal mental state even if you like, and may feature as some activity that contributes to mental states (incuding that tending an individual to avoid things that may result in horror, which requires some practical imagination).
I wonder and doubt that it’s necessarily the same thing as terror. It might overlap.
How progressed are we after a half century or more of horror as entertainment, or has it always been entertainment right back to the ancestral environments?