Want to know one of the biggest lies people will tell you? That they don't care about their clothes or their looks, and that they think fashion is stupid.

While it's true that you do meet the occasional person who's still wearing the same faux tuxedo T-shirt and Vans he wore in 1985, caring about clothes is about as basic a human urge as building shelter.

There's a ton of evidence to support this. Remember the wild-and-crazy dress Jennifer Lopez wore to the Grammy Awards a while back? Of course you do. It's the green and blue one that looked like a sheer tablecloth held strategically in place by some sort of magic Velcro. (Either that, or Lopez's hands, which were almost always folded modestly in front of her bellybutton.)

The photograph of Lopez in this dress quickly became one of the most popular downloads on the Internet. Soon, even secret staying power of the dress was revealed: toupee tape (which wouldn't exist but for the fact that men, who supposedly don't care about fashion, do care about being bald).

So, no matter how much people will tell you that fashion is frivolous, and that they really don't care, the truth is, it has been important to people for thousands of years.

According to Genesis 3, the first thing Adam and Eve did when they ate the forbidden fruit was to put on fig leaves. (They're lucky the Garden of Eden wasn't full of nettles and holly trees.) According to some scholars, this had more to do with the concept of shame. But to me, shame is not the most compelling explanation of why we dress up like we do. It may get people to put on a fig leaf, but what made Jennifer Lopez wear that crazy dress?

My favorite theory about the history of fashion is that clothing is designed to attract mates. But I think it runs deeper than that. Lopez obviously has no problem getting a date. So, why did she need to dress wildly to attract attention? To build her stock as a celebrity--kind of like wolves struggle to become the alpha males and females.

Like wolves, humans have behaviors that establish their dominance. But we also do it through decoration. We didn't come in particularly vibrant colors, like birds and reptiles. We don't have loose skin we can puff up, or feathers we can stick out to send a non-verbal message. So, we use clothes or adornments instead. All human societies have done this--even the ones that live in warm enough climates not to need clothing.

We also use clothes to tell the world who we are and what we believe. You're probably doing it right now.  

Let's say you wear clunky shoes. Unless you're "a very short rock star," Royer says, this kind of show is your way of telling the world that you care about style.

And if you're a man, your personality is most likely to come out in the sneakers you choose.

In the 1500s, European aristocrats wore ridiculously long shoes. The longer the shoe, the wealthier and more virile the wearer was considered to be. It actually required Papal intervention to curb this trend.

In the United States, we've continued to send messages with our shoes. For example, the women's opera boot of the mid-'1800s might look a bit fussy and girly today, but it actually was a proverbial step forward in women's liberation. Before that, only men were allowed to wear boots.

In the 20th century movie stars like Marilyn Monroe made the stiletto heel popular. This shoe was really about a woman's sensuality and power, says fashion psychologist Emily Cho. Next time you see a woman wearing one, you know what she's trying to tell you.

So what does it all mean? Here's what the experts say:

• The passion for fashion is human nature--and maybe even deeper. Even animals get into it, psychologist Cho says. Pack animals have been known to kill members whose fur loses their luster--a sign of weakness.
• It's a kind of language, a language you can have fun speaking. Just as your shoes tell whether you're all work or all play, things like crazy Grammy dresses and revealing shirts say, "Notice me!"  
• People will judge you by your clothes. Even if you're just wearing the basics, you're sending a message whether you want to or not. So, you might as well say what you want to say--even if it's that comfort matters more to you than anything else.