If you dress according to societal dress codes (and those of work and school) you are perceived to be smarter and more conscientious. All students worked on this as part of a research assistantship.
Gurung, R. A. R., Brickner, M., Leet, M., & Punke, E. (in press). Dressing ‘In Code’: Clothing rules, propriety, and perceptions. Journal of Social Psychology.