Send this email to everyone in your address book, and you'll receive $321 from Bill Gates or Steve Jobs. Don't lick the envelopes at your local ATM, because a madman has put poison on them. Forward this email to help find a missing girl. We've all received these relatively harmless yet annoying email hoaxes, chain letters, and urban legends. But why do some of us fall for them?

At least 10 times a day, I receive these email hoaxes in my inbox and usually press the DEL button before you can say "Nigerian bank scam." But aside from greed or gullibility, why do so many of us fall for these ridiculous claims? Can forwarding an email you receive to seven people really make wishes come true? Of course not. But I have some theories on why we succumb to hoaxes:

• Heartstring tugging Take a look at those emails with photos of "lost" children, accompanied by a horrible sob story. Unless you're a heartless brute, it'll evoke some sort of emotional response -- which is how they get ya. A similar thing happened after Sept. 11, with fake pictures of people on the World Trade Center's observation deck just before impact.
• Proximity Email hoaxes and urban legends might seem more plausible when they happen close to your home. This includes emails you might get from someone in the same city that says someone is attacking women at a shopping mall that's right around your house (the villain asks you to smell "perfume" in the parking lot, but it's chloroform!). Because it hits home, you might tend to believe it more.
• Credibility Letters you receive in your email inbox might seem legitimate if they’re (allegedly) from a credible source, such as a president of a large company, a politician or a tech-savvy relative. In other words, you might tend to believe something is true when it's not, because of who is signing their name at the end of the email. This is especially true with emails that contain company letterhead of a familiar logo.
• The ol’ testimonial Just like a TV infomercial, when the email hoax begins with a “real” testimonial, you might be suckered into it. For example, I recently received one that said something like, “Forward this email to everyone, and put your address at the bottom, and AOL will send you a check for $290 -- my sister-in-law did this last month, and she just received her check yesterday!” Ya, right.
• Media coverage When an email hoax cites some sort of media coverage, like, “This was on Oprah yesterday,” or “I read this in Saturday's Wall Street Journal,” you may be more inclined to fall for it since it falsely adds legitimacy. I recall getting an email about a proposed five-cent email tax, and it began with, “Not sure if anyone saw this today on Good Morning America…” Yadda, yadda, yadda.

So, folks, please don’t be so naïve -- chances are if something sounds too good to be true, it is. And if you believe an African billionaire wants to give you a couple of million dollars for helping him bring funds into the country, boy, do I have some swampland in Florida to sell you!