I have been thinking about stress over the last several days, and how stress affects my life and those around me.
Stress does have a physical component.
I used to keep tropical fish–I intend to again some time. You can learn a lot about how life works by keeping fish.
Take convict cichlids for example. If you keep a half-dozen or so in a large aquarium you will soon have a couple that form a pair. They chase off all the other fish (which usually hide behind or under rocks), clean off a rock, and sooner or later lay fifty to a hundred eggs, which they guard until they hatch. They then guard the young until they become overwhelmed by the pressure and chase them off, or until you remove the young to a different tank.
If the fish that were originally in the tank with the pair remain in the tank they will be under a great deal of stress. They will stay small while the reproductive pair continue to grow. You will end up with two large, healthy fish, and a number of smaller ones that constantly hide under rocks.
That is all a consequence of stress.
If you move the rocks around sometimes the dominance hierarchy can change, and different individuals will take over. The aggression is aimed more at keeping and holding territory than being directed at individuals, although that is a part of it.
So can we move the rocks in our lives?
The roused bear 