Social consensus. "Everybody is doing it, and you don't want to be the one that's left off the bus. You want to be with the 'in' crowd," she says.
Reciprocity. "The idea behind this is the concept of 'I do something nice for you, you do something nice for me,'" Walsh says. "There's been a lot of research that's been done that shows when you give someone something, that person is more likely to give back to you."
Scarcity. "It's used to create a false sense of urgency—something is time-limited. They might say it's quantity-limited. They also might claim something is exclusive," Walsh says. "This is the idea that this opportunity is only available to a select group of investors, and you are one of them."
According to Walsh, the best scammers will use these tactics on a mark without the mark realizing that he or she is being targeted.
How to fight back. Walsh says the best weapon against cons is simple: Ask a lot of questions.
"The process is designed to weigh you down so that you're in an ether and not making a rational decision—you're making an emotional one," she says. "The best way to avoid this situation is to ask questions. If you make the con's work difficult, they'll back away."
"You've got to do your own independent research," adds AARP's Hurme. "You have to verify the info and not let the glitter and glamour of a brochure that is not a regular prospectus get in the way of prudent caution."