Exposing lies in WhatsApp chats and other messengers

Are you being lied to in one of your chats? An expert has revealed to atechbook how you can recognize exactly that!

Actually, lies have short legs – that’s what we learned in our childhood. Nevertheless, according to a representative survey, around 60 percent of Germans tell lies every day. While it seems much easier to recognize untruths face to face, this is much more complicated in messages via mail, SMS, Facebook Messenger or WhatsApp.

Recognize lies like the pros

According to the survey, as many as 23 percent of Germans lie in writing. But how can you expose whether you have been lied to? Prof. Dr. Peter Kosta from the University of Potsdam has revealed to atechbook which clues can unmask lies. In his work as a forensic linguist, the expert deals with language as well as lies and is Member of the Germanic Society of Forensic Linguistics. S The BKA, Scotland Yard and Interpol have already used his expertise. He examined, among other things, letters of confession, suicide notes or threatening letters.

“In direct conversation, additional features such as posture, facial expressions or gestures can also be assessed,” says Peter Kosta. Nevertheless, written texts can also reveal lies, but this usually happens in a more hidden way and is therefore more difficult to find out.

In general, the expert also makes it a point to judge multimodally – that is, to decide on a case-by-case basis and not to jump to conclusions.

Also interesting: the funniest and most embarrassing typos in WhatsApp chats.

Be careful with these words

In fact, though, there are. Words by which you can tell that the sender is not writing the truth. Kosta calls these signal or fake words. Especially when adverbs appear in texts, recipients of the message should look very carefully.

According to Kosta, the following statements in particular are treacherous:

“Honestly said” or “honestly.”

“in fact”

“In any case” or “in any event”.


“The sender tries to emphasize his claim once again,” says Peter Kosta. Recipients should therefore ask themselves why the sender of the message is emphasizing his or her previous statement once again, such as in the examples: “I will definitely call you tomorrow” or “You can count on it”. “In such cases, suspicious messages should be assumed to be the opposite of the truth. However, the sender tries to disguise the untruth as truth,” Kosta says. Especially if the person writing constantly tries to convince you to write the truth, without you yourself disbelieving a statement, this is an indication of a lie, he says

Last year, researchers at Cornell University in New York published a study looking at WhatsApp messages. They concluded in the survey that some words can imply lies. Especially non-committal words such as “certainly”, “try” or “some” should be used with caution, according to the scientists. In addition, men and women would lie differently in WhatsApp messages. Women primarily used the word “I” when lying, while men used the word “my” more often.

It’s the length that counts

Likewise, the length of the message can expose liars, because it also matters. If the text length were to change abruptly all at once, this could also be a sign that the sender of the message is not writing the truth, Kosta said.

Cornell University also published a study suggesting that the length of a WhatsApp message exposes liars – with lied longer than honest texts. According to the study, truthful messages consisted of an average of 7.4 words, while swindled messages were around 8.2 words. Broken down by gender, the difference is particularly striking for women: in honest texts, they wrote an average of 8 words in a WhatsApp message, whereas in a lie, they wrote 9.1 words. For men, a lied text is much more difficult to recognize by its length: 7.2 words and thus only 0.2 more than in an honest message.

However, this is not always the case, he said. “In emotional moments, texts are usually longer,” Kosta, the linguist, knows. In addition, the choice of words and expressions also depends on one’s own personality. Therefore, a long message is not always a clue to a lie.

Compare with previous messages

“Whenever the usual writing style changes, you should be suspicious,” Kosta says. That’s why it’s of great importance to compare texts from a sender to notice possible changes and conspicuousness, he says. “The key is the comparison itself. When looking at a text, ask yourself: What do you recognize and what deviates from the norm of the writer,” says the expert.

However, changes in writing style can also have completely different reasons, deviations are not always a sign of a lie. The sender may have been in a hurry, for example. “So do not conclude lightly,” advises the linguist.

Peter Kosta himself does not even know if he has ever lied. “Honestly, I don’t like liars,” Kosta says. That’s why he enjoys exposing liars so much. Maybe also because he wanted to be a criminal investigator when he was a kid. And somehow that’s what he’s become now: A language policeman, so to speak. With his tips, you can now be one, too.