Re: World War Z ratings/spoilers
There's no indication of anything like that in the film, and I highly doubt they'll go that way in the sequels. It's implied to just be a instinctual thing, which is silly, but whatever. I'd chalk it up to silly pseudoscience on the part of the writers before I start concluding that that was all part of an elaborate plan to show that the zombie virus is some kind of super-intelligent malevolent entity.
My name is Ozymandias, king of kings: Look on my works, ye Mighty, and despair!
Nothing beside remains. Round the decay
Of that colossal wreck, boundless and bare
The lone and level sands stretch far away.