When it comes to work attire, many of us are worried about the message our fashion choices send to colleagues. But what about the message our clothing sends to us?

What we choose to wear to the office or factory can actually make us smarter or dumber, found one recent study. And that’s bad news for employees who think it’s casual Friday every day.

“Clothes can have profound and systematic psychological and behavioral consequences for their wearers,” according to a study on the effects of clothing on employees by professors at Northwestern University’s Kellogg School of Management, which was published in the recent issue of the Journal of Experimental Social Psychology.

The study found that work garb associated with “attentiveness and carefulness” actually makes workers more attentive and careful.

In testing the theory, the researchers used a lab coat on their subjects and looked at how wearing the coat impacted their work. It turned out, the study found, that “physically wearing a lab coat increased selective attention compared to not wearing a lab coat.”

So does that mean shorts and miniskirts make you dumber? It depends.

“To the extent that a person associated high heels and miniskirts with less intelligence, then it could make a person less attentive,” said Adam Galinsky, a professor of ethics and decisions in management, and a coauthor of the article. “But if a person associated those clothes with a commanding presence then wearing those clothes could make them more assertive and more attentive.”

Galinsky calls the process of how fashion influences us, “enclothed cognition,” and when that happens, individuals are mentally giving the clothing they’re wearing “symbolic meaning.”

The research may lend support to companies that impose dress codes. A draconian clothing policy implemented by Swiss bank UBS in 2010 that called for workers to wear certain types of underwear, among other restrictions, was ridiculed around the globe, prompting the bank to revise the code last year.

But maybe UBS was on to something after all.

Galinsky’s research, however, stopped short of offering fashionista advice on what not to wear to work, and he acknowledged in the study that age-old questions such as whether an expensive suit makes you feel more powerful or whether a uniform makes a police officer more courageous have yet to be answered.

“Answering these kinds of questions would further elucidate how a seemingly trivial, yet ubiquitous item like an article of clothing can influence how we think, feel, and act," the article noted. "Although the saying goes that clothes do not make the man, our results suggest that they do hold a strange power over their wearers."

They also give a whole new meaning to the phrase "a smart-looking suit."

Related: Whatever happened to casual days at work?