People usually speak slower and put less emphasis in the middle of words when telling a lie

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How to spot a liar: people usually speak slower and put less emphasis in the middle of words when telling a lie, study finds

  • Researchers synthesized voices that pronounce words in different tones and pitches
  • This was to mimic the ‘sound signature’ people use when they lie or are honest
  • They then had volunteers listen to sounds and judge words as fair or unfair
  • They found slower speech and less emphasis was a signature for dishonesty

By Ryan Morrison for Mailonline

Published: | Updated:

When someone tells a lie, it’s possible to catch them – because they’re more likely to speak slowly and put less emphasis in the middle of words, according to a study.

Researchers at Sorbonne University conducted a series of experiments to understand how we decide whether a speaker is fair based solely on our voice.

They found there was a signature in a liar’s voice – slower speech and less emphasis on the middle of a word – that the brain can automatically detect – even when they’re not actively trying to determine whether someone is being honest or not.

It is hoped that in the future the find can be used to develop ‘light tools’ that allow the police to determine whether a criminal is lying.

Researchers at Sorbonne University have conducted a series of experiments to understand how we decide whether or not a speaker is fair based on our voice alone. Stock image

Researchers at Sorbonne University conducted a series of experiments to understand how we decide whether a speaker is fair based solely on our voice. Stock image

PROSODY: THE MELODY OF A WORD

Researchers found that the prosody of one word can bear a signature that allows people to determine the honesty of another.

Prosody has to do with the melody of speech – that is the pitch, speed and intensity of a spoken word.

Intonation, tone, emphasis and rhythm are also aspects of the prosodic signature.

It can reflect the speaker’s emotional state and any presence of irony or sarcasm that is spoken.

A study by French researchers found that prosody of a lie involves slower speech, less emphasis on the middle of the word, and increasing inflection at the end of the word.

The study’s authors say that if you want to be seen as honest and confident, speak faster, put more intensity in the middle of a word, and drop the tone at the end.

These subtle changes in the way we speak are ‘automatically’ registered by the brain and it happens in a number of languages, including English, French and Spanish.

The French researchers used vocal signal processing to create arbitrary pronunciations of words, including rising and falling pitch.

They then asked several groups of volunteers whether the words were spoken with certainty or fairness.

The success of human collaboration depends on mechanisms that enable individuals to detect unreliability in the people they regularly deal with.

Despite being a vital part of human society, researchers aren’t sure what sensory inputs people use to determine the reliability of another.

To solve this, the French researchers used a data-driven method to decode the prosodic characteristics that stimulate listeners’ perceptions of a speaker’s certainty and fairness about the duration and loudness of the pitch.

“Here we show that listeners’ perceptions of the certainty and honesty of other speakers from their speech are based on a common signature of a prosody,” they said.

The study's authors say that if you want to be seen as honest and confident, speak faster, put more intensity in the middle of a word, and drop the tone at the end. Stock image

The study’s authors say that if you want to be seen as honest and confident, speak faster, put more intensity in the middle of a word, and drop the tone at the end. Stock image

Prosody refers to the ‘melody’ of a phrase or word: the pitch, speed and intensity.

‘We find these two kinds of judgments [certainty and honesty] rely on a common prosodic signature perceived independently of individuals ‘conceptual knowledge and native language,’ the study authors wrote.

Finally, we show that listeners automatically extract this prosodic signature, and that this affects the way they remember spoken words.

“These findings shed light on a unique auditory adaptation that enables human listeners to quickly detect and respond to unreliability during language interactions.”

They found that this “intrinsic” ability to detect “signatures” in a voice could be used to determine whether the person is telling the truth or peddling porkies.

“Prosody consistently provides information about the truthfulness or certainty of a proposition,” the team wrote.

They are now trying to understand how speakers produce such prosody based on their intentions – rather than just how people perceive different statements.

The findings are published in the journal Nature Communications.

How to tell if someone is lying to you: see if they are impersonating your actions

Every poker expert knows the power of ‘tells’ – small actions that indicate that a player is trying to trick his opponent.

Now, a new study suggests that one of the best ways to find out if someone is lying to you is to see if they are impersonating your actions.

Dutch researchers at Erasmus University Rotterdam used motion capture to track liars’ behavior as they told ever-increasing lies to someone else.

We can unconsciously imitate the behavior of others, and we are more likely to automatically mimic them when the brain is hard at work, the researchers explained.

Because it’s more difficult for the brain to be dishonest than it is to tell the truth, we tend to impersonate our victims when we’re deceitful, they added.

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