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Detecting Online Liars

Catching Liars OnlinePeople who lie on online dating sites have a huge advantage: Most people can’t identify a liar. But researchers have discovered ways to figure out just who is lying in their profile.

Using personal descriptions written for Internet dating profiles, Catalina Toma, Ph.D., a communication science professor at the University of Wisconsin-Madison, and Jeffrey Hancock, Ph.D., a communication professor at Cornell University, have identified clues as to whether a person is being deceptive.

The researchers compared the actual height, weight, and age of 78 online daters to their profile information and photos on four matchmaking websites. A linguistic analysis then revealed patterns in the liars’ writing.

For example, the more deceptive a dater’s profile, the less likely they were to use the first-person pronoun “I.”

“Liars do this because they want to distance themselves from their deceptive statements,” Toma said. Liars employed negation, a flip of language that restates “happy” as “not sad” or “exciting” as “not boring.” They also tended to write shorter self-descriptions in their profiles — a hedge, Toma said, against weaving a more tangled web of deception.

“They don’t want to say too much,” Toma said. “Liars experience a lot of cognitive load. They have a lot to think about. The less they write, the fewer untrue things they may have to remember and support later.”

Those who lied about their age, height or weight also were more likely to talk about work or life achievements, rather than appearance, the researcher noted.

Once the researchers had these tools, they were able to identify the liars about 65 percent of the time, Toma said.

In a second phase of the study, Toma and Hancock asked volunteers to judge the person’s trustworthiness based solely on the written self-descriptions posted on their online profiles.

“As we expected, people are just bad at this,” Toma said. “They might as well have flipped a coin. They’re looking at the wrong things.”

About 80 percent of the 78 profiles in the study, which was supported by the National Science Foundation, strayed from the truth on some level, she adds. “Almost everybody lied about something, but the magnitude was often small,” Toma said.

Weight was the most frequent transgression, with women off by an average of 8.5 pounds and men by 1.5 pounds on average. Half lied about their height, and nearly 20 percent changed their age.

Toma says the findings are not out of line with what we know about liars in face-to-face situations.

“Online daters’ motivations to lie are pretty much the same as traditional daters’,” she said. “It’s not like a deceptive online profile is a new beast, and that helps us apply what we can learn to all manners of communication.”

Don’t go looking for a dating site that employs Toma’s linguistic analysis as a built-in lie detector.

“Someday there may be software to tell you how likely it is that the cute person whose profile you’re looking at is lying to you, or even that someone is being deceptive in an email,” Toma said. “But that may take a while.”

The study was published in the February issue of the Journal of Communication.

Source: University of Wisconsin-Madison

Detecting Online Liars

Janice Wood

Janice Wood is a long-time writer and editor who began working at a daily newspaper before graduating from college. She has worked at a variety of newspapers, magazines and websites, covering everything from aviation to finance to healthcare.

APA Reference
Wood, J. (2018). Detecting Online Liars. Psych Central. Retrieved on December 4, 2020, from
Scientifically Reviewed
Last updated: 8 Aug 2018 (Originally: 14 Feb 2012)
Last reviewed: By a member of our scientific advisory board on 8 Aug 2018
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