A friend of mine has been dabbling in online dating for a couple of years. I look forward to hearing the stories of her occasional encounters. Sometimes they are entertaining, sometimes sad and sometimes hopeful.

But once in a while she has one that is outrageously funny, and that’s usually because somebody has lied in his profile and the lies unravel quickly when she meets him. Take for instance the guy whose profile picture was from 15 years earlier when he had a full head of hair, or the “successful stockbroker” who lived in his mother’s basement.

Pattern of Lies

While it’s unfortunate that people feel the need to lie in their dating profiles, the truth is that we are all so bad at spotting the lies that the liars often get away with their deception. In fact, a study in last year’s Journal of Communication revealed that online daters truly are terrible at discerning truth from fiction in dating profiles, and provided some clues to deception that could be helpful in detecting it in any kind of writing.

Using internet dating profiles, Catalina Toma, a communication science professor at the University of Wisconsin-Madison and Jeffrey Hancock, communication professor at Cornell University, identified clues to whether the author was lying. They compared the actual height, weight and age of 78 online daters to their profiles and photos and performed a linguistic analysis to reveal patterns in their writing.

Absence of “I”

The researchers found that the more deceptive a profile was, the less likely they were to use the pronoun "I." We already know that in investigation interviews, liars try to distance themselves from their deceptive statements by using the third person, but now we can extend that theory to written statements.

Negation

The researchers also found that the liars often employed negation. For example, they might write “not wealthy” instead of “poor”. They also found that the liars wrote shorter descriptions, perhaps to avoid weaving a more tangled web of deception, speculated one of the researchers. The less they write, the fewer lies they have to remember later.

Avoidance

The deceptive writers who had lied about their age, height or weight or whose photos were not good representations of their looks were less likely to write about their appearance, the researchers noted. These writers wrote more about work and life than about their physical traits.

Applying the Rules

Armed with the knowledge they gleaned from the study, the researchers went through the profiles again and were able to correctly identify the liars about 65 per cent of the time. It’s still not a great record, but as experts in deception have noted, good lie-detecting skills come with practice.

No matter how good a liespotter you are, writes Pamela Meyer in her book Liespotting, you can improve.

And detecting deception is a lot easier to practice when you know what to look for.