Welcome to Gaia! ::

This is a little older thread, but since psychology is my field of study I think I'll bump it up a little.

It really irritates me when I see people refer to psychology as a pseudo-science. I can tolerate it when people call it a "soft science", but the truth is that psychology is merely a young science.
You must also consider that psychology is a very broad term that encompasses many different areas. In general terms, psychology is the study of the human mind. The human mind is difficult to study because we are very limited by our ethics. Rather than creating situations to test response, we have to wait for them to occur naturally because creating them ourselves would be harmful and unethical. That makes psychology a difficult thing to study.
For example, we are still trying to work out how early childhood trauma such as child abuse effects the brains development. Obviously the easiest way to discover such a thing would be to create an experiment where there was a control group and a group of children who were abused and traumatized while all other variables were controlled. We could quickly answer the question of how abuse and trauma effects the brain that way, but who wants to traumatize and abuse little children? Obviously we just can't do that. Instead we can only study children who have already been abused and then there are dozens of variables that complicate things. There are too any variables in studying humans to be able to make the kind of conclusive discovers that are made in other areas of science.

Gotta agree with you, psychology is a science not a pseudo science. Most theories have a quantitative basis is hard empirical evidence, rigorous testing to ensure the results are valid and reliable. (Not to mention all the statistical analysis, though "lies damned lies and statistics" can often apply if you have the mind for it )
Even Qualitative psychology has these guides,(different but there) to see that the data is in accordance with things like the grounded theory(its gotta be grounded in evidence).
Also I must point out against the measurements of 'norms' other sciences like chemistry, you test an element it will remain the same. It doesn't matter where you get it from hydrogen is always one proton and one neutron.
People though, how can anyone ever get a statistical norm? You draw you sample from how many and who ever you can get in your target population.
You can't test the entire human race to get a bell curve and find the norm. All you can do is draw evidence where you can; and expect everyone to try and prove you wrong. Psychology has the strength as a science, that you know and realize that what you study is dynamic. Yes you can never say we have absolute proof, only support (personally I think that’s a good thing). This also means that it can't stagnate, therefore everyone theorist has the incentive to make the theory or hypothesis as water tight as possible before it gets ripped apart by the rest of the psychological community.

However, I also much prefer basing my ideas more on inter-related traits rather than physical evidence. Is that still psychology, or a different study of human behavior?

Yes. There’s many different branches of psychology( and sociology too) each takes different methodologies and idea's(hell there's even an aura machine where I study , though don't ask me how it works I haven't a clue).
Correlations, case studies, lab studies, interviews there's loads of different ways to study a phenomenon each has its own weaknesses and strengths.

Doesn't have always to be ‘solid’ physical evidence, it just depends on what you actually want to study and what kind of evidence is best.

Physical evidence is sometimes overrated, because you may draw the wrong conclusion by interpreting the data.
That and it's very easy to move the numbers around make statistics jump through hoops to show what you actually want (though this may not be good science but it happens)
For some stuff like the lived experience there's not way you can force a measurement scale.