I think that Yvain is reversing good times and bad times. In the EEA people generally did not get their food from things that they made or planted. They got their food from things that they hunted or searched for. Which means that they didn't have anything to defend in bad times. So this is the way I see it:

Survival Mode/: What you enter when you see a reasonably clear way to survival. You continue to do things the way you know that it works. You try to preserve the status quo, because the status quo is to your advantage. You accumulate wealth if you can because 1)there's a reasonable chance that you'll get to use it and 2)it might help you stay in your good situation longer. You are ready to fight other tribes to keep your place in the sun (or more realistically your place by the water), but you don't go looking for trouble. etc

Exploration Mode/Normality: What you enter when times get tough. You move on (call it "explore" if you think that sounds better) because the place you are can't sustain you or is dangerous. You look for new sources of food and other things you need because the old ones are not enough. You don't care about many material things because anything you keep will encumber you, thus reducing your chances of surviving even further. etc