Yes. This is what you should do. Some shorts and a polo would be appropriate.
No.
For a lab job? Not really....
No... polo and shorts.
Ok for a girl... its different.
Please do not wear a dress shirt and dress pants to an interview. Let me tell you whats going to happen if you wear a dress shirt and dress pants to your lab interview.
The moment you walk in the door, all the postdocs and graduate students (who are wearing camo shorts and a tshirt of either their undergrad institution or a rock band) will look at you and form an impression of you. They will think you are some dorky little kid who dressed up to impress the PI. When he is conducting the short 15 minute interview (which might actually be in the lab when he is doing experiments, and not giving you his full attention), he probably won't notice that you dressed up.
The pecking order in the lab goes like this
PI ---> Lab Managers ---> Senior Post docs -----> Junior Post docs ----------------> Senior Graduate Students ----------------------------------------------------> New Graduate Students ---------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------> Undergraduate students
Before you even walk in that door, they have already formed the impression that you are a cute little tyke who doesn't know what he is doing and that you will drag them down.
I am being dead serious. No guy dresses up... I have never seen any guy do this. Please don't.