There's some game theory, some evolutionary biology, some cognitive psychology. It's all good stuff.
The most interesting, to me, is this bit about halfway through:
I don't think I've ever heard the left/right brain divide categorized this way, but it makes sense. "Logical" and "sensible" aren't necessarily the same thing. Asimov makes this point in several stories; "Reason," a short story where a robot gets religion (and demonstrates that logic can prove anything, if you start with the right postulates), and The Caves of Steel, a novel that concerns a detective who worries about his robot partner replacing him as they solve a murder together. The detective in question discovers while working with the robot that this is not likely to happen, and one of the reasons is the difference between "logical" and "rational." Asimovian robots are both perfectly logical and perfectly irrational, and it turns out that being rational counts for more in terms of being human.
But for better or worse, the neocortex is dominated by its left hemisphere, which tends to be not only logical but gullible, rationalizing and self-deceiving. You know that voice inside your head that says everything is all right, there's nothing to worry about here, just ignore your gut feeling and get on with the task at hand? That's your brilliantly stupid left brain talking, and if you listen to it long enough, eventually it will kill you.
(Those summaries are horrible bastardizations, especially the Caves one, so go read them both to find out what I'm actually talking about. "Reason" is found in the book I, Robot.)
I'd argue that this ability to clamp down on fear, even when it might be more useful to listen to that fear, is a direct result of the brain's "right sided" imaginative, intuitive abilities. Human's aren't limited to fearing real things; we're perfectly capable of inventing things to fear, so there needs to be some mechanism to determine between reasonable and unreasonable fears. Sometimes this mechanism goes a bit haywire, as most mechanisms do.