It's the rare little girl who isn't told that lying is wrong and something you never, ever do. That advice aside, it's the rare adult woman who doesn't regularly lie to some degree or another -- maybe without even knowing it. Unlike men, who lie mostly to get something they want (like sex or a promotion), women usually lie to hide the truth. They lie to protect themselves and other women; they lie to, for, and about their children; they lie about love and sex; they lie about money; and, perhaps most sadly, they lie about their own happiness. Since we all start intending to be good girls who speak only the truth, just how did this culture of women's lies get perpetuated?

According to Susan Shapiro Barash, author of "Little White Lies, Deep Dark Secrets: The Truth About Why Women Lie," being told to "be a good girl" is really code for "keep your secrets safe." Our mothers patted our heads and set us off on the path to keeping our secrets and telling lies in order to help us garner some power in a life that might otherwise be powerless. Lies, then, can help level the patriarchal playing field. In this culture, "women still feel the need to lie as a coping or survival mechanism," Shapiro says. When you are not in charge, you lie to save face (and maybe your own neck) and to look better in the eyes of the ones running the show -- whether that person is your boss, your husband, your neighbor or the traffic cop frowning at you on the side of the road. To put it in sporting terms, for men, telling lies is more of an offensive maneuver; for women, lying can be a major form of defense.

Women also lie to hide their true feelings -- this is the birth of the "little white lie" we tell so we don't hurt someone's feelings. Other, more insidious lies are the ones we tell ourselves. "The lie just seems so much easier than the truth," says Barash, who interviewed 500 women for her book. "Sometimes these internal lies are even subconscious, because the truth is just too painful to acknowledge, even to ourselves." Consider the woman whose husband is abusive but she denies it because it would be too financially or socially difficult to leave.

Ultimately, women lie because we feel like so much is our fault. "A friend said to me, `How could you write this book? Isn't it hard enough for women?'" Shapiro says. "But I actually wrote it to allow women to be set free from the need to lie." Life -- and telling the truth -- would be much simpler for women if less were expected of them.

In Shapiro's experience, the lies women tell typically fall into specific categories of deception. "Compassionate lies" are almost unique to females. These are the "white" lies that soften the harsh edges of reality and often sound like gentle cheerleading: "That dress looks great on you," "Of course I don't mind if you date my ex-boyfriend," or "That dinner was fabulous!" If a man tells you an outfit doesn't make you "look fat," he may simply be maneuvering to get you both out the door to meet his friends at the bar. When a girlfriend says, "Sure, you can rock a tiny bikini," she may just be protecting your friendship. The problem with these compassionate lies is that women take it upon themselves to protect others, which is an isolating position -- not to mention the fact that compassionate lies can often backfire.

The "betterment lie" has the ability to improve the overall situation. Shapiro calls it the "bread and butter of female lies." It typically involves women doing what they feel they simply have to do for the people they love -- usually their husbands and children. These lies, for instance, often paint a rosier picture of family life or of a woman's sense of satisfaction with that life. Women also tell betterment lies to other women as part of the age-old game of female rivalry.

A "survival lie" is used to protect a secret that seems too large for honesty, a lie a woman feels is necessary to preserve her current living situation. These are the lies about babies conceived when a husband was out of town or about the real reasons for being let go from a job. These are the lies that are sometimes carried out through silence as much as they are with words.

Interestingly, women justify beneficial lies as being more important than the truth. Lying about finances, such as credit history, in order to move forward on an important business deal, for example, could be explained away as "hurting no one, but helping someone."

It's nearly impossible for women not to lie, insists Barash. "There are certainly lies that keep us civilized and keep a smooth social machine going." But other lies are devious or damaging, and can even prevent someone from getting the help they need, such as in the case of an abused wife or a child with a drug problem. Mother likely knew best when she advised us not to lie. Feminist poet Adrienne Rich offers another compelling argument for why women should lie less: "When a woman tells the truth she is creating the possibility for more truth around her." HL