It's a frequent scenario. Two young con artists walk a retired high school teacher to the bank and fleece him out of $17,000. But why did the man, in his 70s, fall for it?
It may be that older people are less able to identify shady characters than younger ones, according to a study by Shelley Taylor of the University of California, Los Angeles, published on Monday in the Proceedings of the National Academy of Sciences.
Adults older than 60 lost at least $2.9 billion in 2010 due to financial exploitation - ranging from home repair scams to complex financial swindles - up 12 percent from 2008, according to the MetLife Mature Market Institute.
To understand why, Taylor and colleagues did a series of studies comparing perceptions of trustworthiness among younger and older individuals. They found older people tended to miss common cues that suggest a person is not trustworthy.
"It's that 'uh-oh' response that people get," said Taylor, who directs UCLA's Social Neuroscience Laboratory. "The younger adults are getting that and the older adults are not."
In one of the studies, the researchers asked 119 people between 55 and 84 and 24 younger people to view a stack of 30 photographs of faces that had been rated by another lab according to how trustworthy the individuals looked. Individuals were rated as trustworthy, neutral or untrustworthy.
When faces in the photos were trustworthy or neutral, the older adults' responses were very similar to those of younger adults. But when viewing faces rated as untrustworthy, the older adults were less likely to pick up on cues.
Next, the team did the same test with a different group of 44 study subjects while their brains were being scanned in a functional magnetic resonance imaging or fMRI machine. Such tests help show which parts of the brain are active during certain tasks.
In the younger study subjects, the brain scans showed significant activity in a portion of the brain called the anterior insula when they looked at pictures of untrustworthy types. But in the older volunteers, there was very little brain activity in this region.
One of the functions of this area of the brain is that it helps interpret sensations in the body that form "gut feelings," according to lead author Elizabeth Castle.
"We saw that older adults didn't get the same level of insula activation that the younger ones did," Taylor said.
"It should be telling them this looks risky, this looks iffy."
To Taylor, this suggests that during aging this portion of the brain becomes less responsive, either because it is degrading or because the neurons that send signals to this region of the brain are not firing properly.
Taylor said her findings contradict the notion that the current crop of post-war seniors was raised during a more trusting time and are simply too well mannered.
"That is not it. It's an age-related trend," Taylor said. "We're going to see this with Boomers and Gen Xers."
Although the study only looked at visual cues of trustworthiness, Taylor said some of the same issues may be at work when seniors get taken in by smooth-talking telephone marketers.
"Cues to deception are carried not only through the face but also through the voice," Taylor said. "In a face-to-face situation, people are using a compilation of the cues they see and hear. It's entirely possible that an analogous process is going on for telemarketing."
The findings appear to agree with what experts on scams and the elderly have long noticed, says Doug Shadel, Washington state director for AARP, a national grassroots organization that represents older Americans.
He said scam artists have admitted in interviews that their main ploy is to get their intended victim "under the ether," or in a heightened emotional state that puts them off kilter.
"They're bypassing that same part of the brain - the frontal cortex, the part that makes you doubt things - and bringing you to the present moment where you're going to make a rash decision," said Shadel.
"It's something that we in the practitioner world have suspected for years. But getting concrete science behind it is really important," added Shadel, a former fraud investigator.
In fact, the findings may help older people avoid such scams.
Taylor's own father was the retired school counselor who got scammed by the two young men, who were homeless and missing teeth. "He thought they were nice young men and he was making loans," Taylor said.
And Taylor's aunt was the victim of telephone marketers who convinced her to purchase fake gems.
Given older people's weakness when it comes to judging whether a person is trustworthy, Taylor advises to reduce the temptation.
"You want to get people to shut it off before they ever have the conversation: to hang up without talking, to throw the mail solicitation away, to not go to the free lunch seminar," she said.
AARP recommends that people never decide to buy something while listening to a sales pitch or reading a mail solicitation. "Always give yourself at least 24 hours so that you have time to engage your rational mind," Shadel said.