In cases such as resorting to human cannibalism to survive, or this story on eating cockroaches vs. people with such nasty associations in our minds we'd have to be starving to death:
http://blog.chron.com/sciguy/2013/10/the-hot-new-farming-trend-in-china-is/
What part of the brain affects such decisions? Aren't those associations emotional?
Where someone might opt to starve to death instead of eat from a dead person?
Where someone could saw off a foot in order to escape and survive?
Is this just survival mode in general, or does it involve some brain functions that differ substantially between empathetic or sociopathic minds.