What is it about hiring technical people?

I know companies don't want to hire people who can't perform. Using interview tests has been around for a long time. Personally, I hate them. If a prospective employer ever reads this, I'm sure I'll be doomed with some type of test. And that's the problem.

I believe employers have the wrong expectations when it comes to surprise interview tests. I believe most employers administer them out of ego rather than necessity. Almost every perspective employee will go through several types of emotions. The least of which is panic. Speaking from experience, when faced with one of these tests, I'm always on the defensive, wondering what they really want from the test, will my coding style be their style, will my approach be what they consider acceptable.

Now, if the test is simply to learn how someone approaches a problem, review their coding style, and as described in the link above, experience how they explain their solution, then I'm all for it. I'm not a walking encyclopedia of syntax. I may not always know the correct syntax from memory, but I might be able to pseudo code something on paper or even a text file, and explain how I would solve the problem.

If I can leave any amount of influence on these types of test is that employers truly look for characteristics of the prospective employee, rather than how much syntax they can recall from memory.

Oh, and to tie in my subject line, what is it about hiring technical people? It seems employers hiring for technical positions are hell bent on testing someone's skills, but don't think twice about testing someone for a product marketing, project management or administration position. If you do, what kinds of test do you perform?