Of course, you want to be smarter. But most of us also want to look smarter. In business and in life, being perceived as intelligent gives you a leg up.

So how do you make sure you come across as clever? Humans are weird animals, and science shows that how smart you look is influenced by a number of unexpected (if not downright bizarre) factors like the pitch of your voice and even whether you use your middle initial.

Some of these are easy to change, some are difficult. New research recently uncovered one trick that's actually dead simple to implement. To look smarter, simply sleep more, a recent study out of the University of St. Andrews in Scotland suggests.

Yet another reason to get enough sleep

As if there weren't already enough reasons to get adequate rest, the study, led by Sean Talamas and recently published in the Journal of Experimental Psychology: General, found that being well-rested isn't just good for your mood, your health, and your cognitive function--it also causes others to see you as more intelligent.

To come to this conclusion, Talamas and his team photographed 190 study participants when they were well-rested and when they were struggling along on little sleep. They then asked others to evaluate the perceived smarts of the people in the images. Those who had gotten enough shut eye were consistently seen as more intelligent.

Why? Apparently it's all down to subtle facial cues, additional experiments that analyzed the participant's' facial expressions with special software revealed. "People over-generalize in judging those with droopy eyelids and a frown as being tired and having a low mood, both of which have a well-documented detrimental effect on cognitive performance," Talamas says. "Therefore, it should be no surprise that many of us find people who look less alert and who have a lower mood as less intelligent looking."

So ponder that the next time you're tempted to watch just one more episode of that addictive TV show rather than hitting the hay like you know you should. And keep these results in mind when you especially need to impress the next day--perhaps for a job interview or big presentation. Anxiety might make it hard, but if you want to look your most competent and compelling, these are the times you really ought to try to get enough sleep.