I do not understand, I turn the roughness all the way up, and yet, these intensely bright spots remain on the mesh. Can anyone explain how/why this is?
Agree with Martin. That screenshot doesn't seem to represent the material that is plugged to what you see in the horse model. Changing the roughness on a diffuse doesn't change the reflections. And the horse model shouldn't have reflections if it only has a diffuse plugged in.