Personal Finance

Why some of us are more vulnerable to online fraud

Here's why you fall for those online scams
Here's why you fall for those online scams

Go online and there are scams everywhere. Some people fall for them, some don't. Why?

A new study by AARP shows that a combination of online behaviors and life experiences can make someone more vulnerable to fraud.

The report, "Caught in the Scammer's Net," found that victims tend to do things that put them at risk, such as clicking on pop-ups, opening emails from people they don't know or signing up for free trial offers. But they're also more likely to be going through a stressful period in their life due to the loss of a job or feeling lonely and isolated.

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Simply put, a negative event in your life can significantly reduce your ability to defend yourself from fraud.

"Signing up for a free trial won't guarantee you'll be scammed, but if you do so during a vulnerable time after you've lost money or lost a job, you may be at a higher risk of being victimized," said AARP Executive Vice President Nancy LeaMond.

Researchers compared the life experiences of victims and nonvictims, based on a nationwide survey of 11,000 adults. They found that online fraud victims have experienced 53 percent more negative life events. They felt more isolated, were twice as likely to have lost a job, worried more about debt and were nearly twice as likely to have experienced a negative change in financial status in the last two years.

Based on its survey, AARP estimates that there are 34 million Internet users who are at higher risk of becoming victims.

"People have to be especially cautious when they've experienced a stressful life event," said Doug Shadel, director of AARP's Washington state office and co-author of this study. "Stress takes up cognitive capacity. You're thinking about the stressful thing. You're not thinking about how to defend yourself against scams, and that makes you vulnerable."

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And the scammers know this and use it to their advantage.

How to fight back against identity theft
How to fight back against identity theft

Jackie Swett fits the AARP profile. The 50-year-old lives alone in the Seattle area and suffers from post-traumatic stress disorder. An Internet novice, she clicked on a pop-up ad that said her computer was infected.

Without friends to ask for advice, Swett did what the cyberthieves wanted—gave them access to her computer and paid $200 for the unnecessary service with her credit card.

"I have a tendency to trust people and by the time the red flags come up, it's too late," she said.

But that was just the start of her problems. To undo the damage done by the scammers, she needed to spend another $500 to have her computer fixed. She had to cancel that credit card. And it appears the scammers put her on a "sucker list," because she's now getting a flood of phone calls pitching bogus offers.

"It's been a real pain," Swett told me.

Fraud fighters need to change their message

Jennifer King is a Ph.D. candidate at the University of California, Berkeley School of Information who has consulted with the Federal Trade Commission about fraudulent websites. She believes AARP is on to something—that this information is another piece of the puzzle that will help fraud fighters do a better job of crafting their message to American consumers.

For decades now, consumer advocates have offered the same advice at the end of every scam alert: "If it sounds too good to be true, it probably is."

(Read more: How the 'one ring scam' can cost you money)

With consumer fraud on the rise, that message has clearly failed to solve the problem. Maybe that's because the scammer's pitch doesn't sound "too good to be true" to that person who is most likely to become a victim.

"We tend to focus our attention on things that are relevant to our current needs," said Jeff Langenderfer, head of the School of Business at Meredith College in Raleigh, N.C. "So, when you're hungry you notice ads for food. If you've lost your job and money is a pressing issue, everything you see that offers a lifeline in some way grabs your attention. You focus on the benefits being promised by the swindler which makes you more likely to fall for the false promise."

AARP has tools to help protect you and your family from all sorts of fraud. The Fraud Watch Network (available to nonmembers) lets you set up email alerts about new scams and find law enforcement warnings from your state. You can also talk to volunteers who are trained to answer your fraud-related questions.

—By CNBC contributor Herb Weisbaum. Follow him on Facebook and Twitter @TheConsumerman or visit The ConsumerMan website.