[For those not familiar with evolutionary psychology, the short version of it is that our psychology is the result of evolution, and generally helps us to survive. However, evolution is a very slow progress, while civilization has popped up relatively quickly, so our brains are still running caveman software and it's maladaptive for our modern world, thus creating a bunch of problems.]

Having not been a caveman for some time, I can't really speak to what their world was truly like, but I imagine that the world of the caveman is composed of things that are basically harmless, and things that are totally life threatening.

A squirrel? Harmless.

A grizzly bear? Will kill you.

Garter snake? Harmless.

Rattlesnake? Will kill you. (Maybe not outright, but you'll be so weakened by the poison that you'll soon die from something else.)

Bobcat? Harmless.

Lion? Will kill you.

Sunny day? Harmless.

Cold rainy day? Pneumonia will kill you.

Fellow tribesman? Probably harmless. But, if not harmless, will kill you.

Man from another tribe? Will probably kill you.

Coyote? Won't kill you, but it'll eat your babies.

Compare that to our modern world. There are few things that are life threatening, but lots of things that suck in a moderate degree. Car wreck? You'll probably survive, but maybe with some broken bones, and you have to get a new car, deal with the insurance, lose some money, etc. Test at school? It only counts for 20% of your grade for the semester, which is a fraction of your overall GPA. Cavemen didn't have "20% of your grade for the semester." Fail a test as a caveman, you bleed out and die.

My theory is that our brains are wired to feel either unafraid of something, or super afraid of it, and aren't really well adapted for feeling a moderate amount of fear. Apply this to approaching, and our brain has to make a choice. Do you feel totally zen, or do you freak out? Your brain knows there is some risk to approaching -- rejection hurts, you might be embarrassed, she could have an overprotective boyfriend, your friends might see you strike out. While all of these things are only small risks, your brain has no choice but to treat them like a hungry grizzly bear. Thus you feel a level of anxiety that is completely out of proportion to the actual risk you're taking. That is approach anxiety.

So what can you do about this? If your brain is telling you the girl is a hungry grizzly bear you're off the hook for not approaching and can't be blamed for being forever alone, right?

Nope. We are more than our caveman programming. We also have logic and experience and free will. Our instincts are but one of many factors that influence our actions -- they are not our destiny.

What you do is come to a rational understanding about the actual risk you are taking (there is some risk here, sure, but it's very small in the grand scheme of things). Then you build up experience by approaching and seeing for yourself that rejection does not result in bleeding out and dying. And most importantly, you learn that despite what you're feeling, you still have a choice about your actions. You are more than your emotions. Your emotions are just information from the old caveman part of your brain, and it's up to you to decide what to do with that emotion. You can either let it completely control you, or you can see that it's out of touch with the real world and ignore what it's telling you.