Exactly: emotioal/instinctive/reflexive behaviour; not reasoning behaviour. All animals have these non-cognitive attributes, and need them, because reasoning takes time that we don't always have available before reacting to danger. The stampede makes sense in this context. The cliff, if present, is a piece of information the herd might have acquired in time, but did not possess at the moment of reaction, so their subconscious calculations did not take it into account. (Which is why the humans, being more intelligent, deliberately drove them in that direction.)
No, this is a different psychological phenomenon. Humans are able to compartmentalize and rationalize. Pigs are one class of thing; pork is quite another. Lamb, oddly enough, in various depictions, is a sweet personification of the virtue of innocence (There are four things seriously wrong with that phrase.) and the food product it becomes after a rather gruesome process has the same name, and yet is regarded quite differently. This ability to detach object from meaning and concept from function is - I believe - exclusively human.
Just as well, too: we've been losing our uniqueness in all the other areas we used to claim. You know how humans hate not being special!