Correct me if I am wrong here, but it's a darn good thing too. How horrible would it be if you got a flight or fight response every time a possible diffuse future threat was mention in passing by someone? I hardly think this example can be characterized as a flaw.
If there's a such a thing as a tipping point, then yes, it's a flaw because your brain won't signal real danger until it's too late to do anything about it.
Redesigning the human body is an old hobby, but a complete understanding of how evolution works and the complexity of the human body (including the brain) should make one hesitate. I've seen numerous things that could be "better" (for example, "let's just get rid of the appendix"), but I've never seen such a redesign that I could actually guarantee was a certainly-better thing. The tradeoffs are ignored.
There's no guarantee that "just" allowing the prefrontal cortex to induce a larger fear response will have anything like the desired effect. You might just end up with a population with widespread, crippling phobias, or, given that the prefrontal cortex is hardly invincible, widespread coordinated responses to non-threats. I think this went by on HN a few days ago and can serve as an example of an excessively-powerful prefrontal cortex overriding survival instincts to terrible, terrible effect: http://lewrockwell.com/orig9/deming2.html (or http://en.wikipedia.org/wiki/Nongqawuse ) (Just take the initial story bit.)
It's just not trivial to re-engineer the brain, and those who are making political points while doing so should be flat-out ignored.
I never said we shouldn't use our powers of reason and foresight. Reason and foresight are NOT the same thing as a fear response. They are, in fact, very different and precisely the response we SHOULD have. The entire reason for reflex action in the body is to respond to immediate threat. The fear reflex is entirely inappropriate when dealing with longer term problems that require thought and foresight.
Besides, even if you could completely turn off these processes, I am not sure that you would want to. By calling it the reptilian brain you make it sound like it is only appropriate for reptiles. The fact is, the same system that tells us instinctually that snakes are threats is probably involved in much of what is called "people skills". Normal social interactions would be at a huge disadvantage without them.
http://www.nytimes.com/2009/07/02/opinion/02kristof.html?_r=...
