I have a hunch that psychologists may find some answers by looking deeply into animal behavior, that of predators. What makes a tiger, wolf, dog, cat, or other predator lovably tender and playful one minute and a stealthy killing machine the next? If you watch predators killing on some of these nature programs, look at their eyes. While they are killing or feeding, there's nothing there, is there? they seem unaware of the writhing agony of their prey.
How can this be? These animals are sensate beings. A moment ago they may have even grieved a death or been upset by the sight of violence. Who is more loving and tender with humans than the dog? In captivity, even tigers may show affection for a human. So predatory animals undoubtedly have feelings.
But look what happens to predators the instant they spot prey: it's like they go into an entirely different mode of being. Suddenly they become killing machines. They are suddenly cruel, and if killing is easy will kill just for sport. For example, some species of primates have been filmed in the wild ganging up on a monkey and ripping it to pieces with manifest glee at the sound of its screams. I saw one such film on PBS and found it so disturbing I changed the channel after but a few seconds. Wolves don't bother to kill a moose they bring down. They just immediately battle for the best position to feed on its intestines, so that it suffers a horrible and very slow death. A killer whale plays with a baby seal it doesn't even bother to eat then when it's dead. Sorry, but that's the truth.
What is suddenly shut off in the brainstem to switch predators into machine-mode at the sight of prey?
The reason I ask is because I had a very weird experience once. I was having terrible migraines. I mean, it was more or less permanent, and I was so sick I couldn't get off the couch or do anything but lay there in a dark and quiet room in pain. I'd had it for about a week. No sleep (just half dozing). The doctor had given me some new medication. Though I hadn't eaten for around three days, I had no appetite.
I found that very strange, and it reminded me of the way a dying animal refuses to eat. In fact, I had recently seen a man dying of cancer have the same problem: he just couldn't eat. When they set food before him, he looked at it with a mixture of disgust and horror. He was literally starving and couldn't explain why, but he just could not eat. The thought of eating turned his stomach.
Well, I found out why when I sat down to eat that day!
That was the scariest moment of my life. That plate of food might as well have been a plate of wriggling worms!
Suddenly I was accutely aware of how gross and gory the action of biting and chewing and swallowing food (the tissues of animals and plants) is. It IS, you know! It's disgusting. Fortunately, however, we're normally totally unaware of how gruesome eating is.
So, I can see why people this happens to cannot explain it. If I weren't a biologist, I wouldn't have realized what was wrong: Something in my brain was malfunctioning big-time. Suddenly, the grossness of eating was so vivid that I had all I could do not to throw up at the thought of putting that stuff in my mouth. I realized that this bizarre reaction to food was caused by something wrong in my brain, some circuitry that normally blocks awareness of these unpleasant sensations to enable us to do such a gross thing as eat ... and to actually relish eating instead.
I also instantly realized that this was a life-threatening malfunction. Whatever wasn't working right in my brain was absolutely essential to survival.
I immediately suspected the migraine medication and threw it out. Then I forced myself to take a tiny bit, fearing that if I didn't -- that if I gave in to this feeling of repugnance -- I'd never be able to eat again, like that cancer patient I had known.
I'm happy to say that a few hours later, I was able to eat a little more. Over the next few days, my appetite returned to normal.
Notice that despite this serious malfunction in my brain, I was quite with-it mentally. I was able to think clearly and realize exactly what was wrong. In other words, only a part of my brain was affected.
Weird, eh? There are mysteries in the brain we know nothing of. When we see food, some of our sensibilities are automatically shut off so that we can view it as something we'd just love to devour.
Similarly, if predators didn't go into machine-mode with certian sensibilities shut off, they wouldn't be able to kill. For them, machine mode is an adaptation necessary for survival. It's what ENABLES them to kill.
What gets shut off in the brain when they go into machine mode? Can it be shut off in the human brain too? Can human beings turn it on and off at will? Or can certain situations like the emotional extremity of combat shut it off? What about narcissists and sociopaths? Is there some way to turn it back on, or to persuade them to turn it back on, so that they can empathize with their own kind and stop viewing others as prey?