From Lt. Colonel Dave Grossman's On Killing [emphasis added] --
When people become angry, or frightened, they stop thinking with their forebrain (the mind of a human being) and start thinking with their midbrain (which is indistinguishable from the mind of an animal). They are literally “scared out of their wits.” The only thing that has any hope of influencing the midbrain is also the only thing that influences a dog: classical and operant conditioning.
That is what is used when training firefighters and airline pilots to react to emergency situations: precise replication of the stimulus that they will face (in a flame house or a flight simulator) and then extensive shaping of the desired response to that stimulus. Stimulus-response, stimulus-response, stimulus-response. In the crisis, when these individuals are scared out of their wits, they react properly and they save lives.
This is done with anyone who will face an emergency situation, from children doing a fire drill in school to pilots in a simulator. We do it because, when people are frightened, it works. We do not tell children what they should do in case of a fire, we condition them; and when they are frightened, they do the right thing.