You can judge someone's personality by what his or her work space looks like. Take Tara Hirshfeld, for example. She's set up her office on a picnic table. She has the laptop, the headset, even the office-type snacks. But there are leaves falling and cars honking. Intuitively, you know she's not an accountant-type. And you surely won't be surprised to hear that she's a student at the School of the Museum of Fine Arts in Boston.

People leave deliberate and inadvertent clues about themselves in their personal space and Samuel Gosling, assistant professor of psychology at the University of Texas at Austin, studies these clues. And Gosling concludes that your co-workers are good at judging what the clues mean even if they don't know why.

Deliberate clues people leave are things like plants, which reveal that you are nice and that you intend to stay a while, and candy, which reveals that you're an extrovert, because you want people to drop by your office and talk. These are deliberate because a person puts them in their office for other people to see. Some clues are deliberate but not other-focused. For example, a pebble you keep from the beach of your first kiss will not be meaningful to someone who doesn't know the story, but it reminds you of something nice. Still something like this gives the co-worker information, and he or she will pick up on the fact that you're sentimental.

Hirshfeld's clues fall into the inadvertent category. For example, when asked about her picnic-bench desk, Hirshfeld says, "I needed some fresh air." She inadvertently conveys that she is non-conventional, which, for an art student seems fine. But for an accountant, watch out. You can give inadvertent clues with a plant, too. "Anyone can buy a plant," says Gosling, "but you need to be task oriented to actually keep the plant alive."

Be careful about all the clues you leave about yourself in your office because your image is at stake. And the image you project might be more powerful than the work you actually do.

So manage your workspace like you manage the colors in your wardrobe, the layout of your memos and all other aspects of your image. In many instances you'll be able to control what you project. For example, if you are trying to be more detail-oriented in your work, but you've killed every plant you've ever owned, don't buy another because your dead plant will just emphasize your lack of attention to detail.

When it comes to projecting a positive image through your personal space, some areas are more easily managed than others. A messy desk is tough. If you keep a messy desk, it's probably inadvertent, and you will have to change behavior in order to clean up your act. It's worth the effort, though. "There is a cultural bias toward orderliness," says Eric Abrahamson, professor at Columbia University Business School, "Messiness is considered bad." Kelly Crescenti, an Illinois-based career coach, concurs: "When people have a clean desk it looks like they get things done and they are productive."

You cannot really know how productive someone is by looking at their desk, says Julie Morgenstern organizing guru and author of Never Check Email in the Morning: And Other Unexpected Strategies for Making Your Work Life Work. But she concedes that "the image issue is giant." So even if you can find everything you need on your pile-laden desk, clean it if you want to look good. Start with a filing system, and Crescenti advises that at minimum, you take the last fifteen minutes of every day to actually use the system and clean things up a little before you go home.

But as with all image management advice, don't go overboard: Everything in moderation. Abrahamson provides a postmodern defense of the messy desk: "Messiness is related to creativity because it tends to juxtapose things that don't normally go together."

"It's the last frontier of messiness," says Abrahamson, and he reports that he's seen computer desktops that rival the worst of the classic desktop messes. Hirshfeld can attest to that. "The last computer I had got very, very messy."

But that might be okay; it's true that your co-workers can accurately judge you by looking at your work space, but it's also true that your computer desktop is a nice place to hide your worst attributes.