So, I'm currently toying around with the idea of a hypercarnivorous sapient race on a planet in my universe, and I'd like to make them scary, but without abiding only by the "rule of cool". (Also note that the science, especially biology, involved in building this world is more important, to me, than the story)
A recent idea of mine regarding these sophonts is to have increased adrenaline (or an alien analogue of adrenaline) production dramatically speed up the transmission of signals inside the brain, and therefore (If I assume correctly), increase the creature's intelligence.
So, my question is: could an increase in adrenaline production cause a wholly noticeable change in the perceived "intelligence" of a species, and if so, how would this work? When I say "intelligence", I'm not really obeying any strict scientific definition; what I mean is that the creature would seem more intelligent in its behavior.
If I recall correctly, during intense moments (such as car crashes), and therefore times when you'd get an adrenaline rush, you take in much more details about the environment. Obviously, the sensory feedback would have to be processed, so perhaps something analogous to this does occur in reality; however, I'm looking for a noticeable difference, perhaps even as drastic as a chimpanzee suddenly thinking like a human.
I'm not (currently) asking if this kind of system could evolve naturally, but that's something I'll definitely be looking into in a future question.