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Um... Little Words Can Signal Big Lies... You Know

Unconsciously spoken words can signal deception.

Key points

  • Words such as "um" and "uh" indicate cognitive load, which liars often experience.
  • Liars tend to use the phrase "I mean" to close the door to contrary opinions, ideas, and additional information.
  • The possibility that a person is lying increases with the observation of clusters of deceptive indicators. No one cue indicates deception.

Little words, often ignored in normal speech, can signal deception.

Words such as um and uh indicate cognitive load. Liars experience increased cognitive load.

The tag words such as You know, I mean, and right are used to seek confirmation, convey information, or to convince listeners. Truthful people convey information and seek confirmation from listeners. Liars try to convince others that what is being said is true.

The word like indicates that what is being said is different than what the speaker actually means.

As with all indicators of deception, a baseline must be established. A baseline can be established by observing a person’s verbal responses during a time when they have no reason to lie. The baseline can then be used to compare the speech patterns of the same person during times when deception is suspected. Changes in the baseline signal the possibility of deception.

As with all indicators of deception, no one cue indicates deception. The possibility of deception increases with the observation of clusters of deceptive indicators.

Um and Uh

Um and uh signal impending delays is speech. Liars need time to evaluate their answers to ensure their lies will be believed. Liars also need additional time to choose the right words to camouflage the truth. Truthful people do not need extra time to convey information. Truthful people narrate information in a smooth logical fashion.

Increased um and uh usage indicates an increased cognitive load. Since liars need additional time to process information, they typically use um and uh more frequently. Um predicts a longer impending speech delay than does uh. Therefore, um may be a better predictor of deception than uh.

You know

Speakers use you know as a device to determine if listeners understand what is being said. You know also establishes a closer connection between speakers and listeners. In other words, speakers move psychologically closer to listeners to ensure their message is received and properly understood. People tend to draw closer to things and people they like. Truthful people are comfortable bringing others into their narratives because they have nothing to hide.


The tag word right seeks input from the listener. Speakers seek to confirm that listeners comprehend the speakers’ messages. Similar to you know, right is a device that draws listeners closer to the speaker. Right also solicits a response from the listeners. Speakers who end their narratives with the word right seek input from listeners. A head nod from a listener signals acceptance of the message. If a listener disagrees with the speaker, the word right serves as an invitation to present a contrary viewpoint. Truthful people do not fear opposing viewpoints because they know that what they said is the truth. Liars rarely invite contrary viewpoints for fear that a contrary viewpoint will expose the lie they are presenting. Liars typically keep their psychological distance from their lie target by avoiding words that invite contrary viewpoints.

I mean

The words I mean express a finality about what is being said. In an effort to maintain the illusion of truth, liars use I mean to close the door to contrary opinions, ideas, and additional information. I mean psychologically distances the speaker from the listener. People distance themselves from things and people they see as potential threats. Liars see their lie targets as potential threats because of the danger of being caught and, therefore, tend to psychologically distance themselves from their lie targets.


The word like signals that what is being said is different than the meaning of what is being said. The truth is the truth. The truth is never like something else. If the truth was like something else, then it would not be the truth. Anything that is not the truth is a lie.


The little words people use can detect deception. However, caution should be exercised because the little words people use can be habit words. Habit words are words people use regularly and almost unconsciously during routine conversations. The importance of establishing a baseline cannot be understated. Once a baseline has been established, then any deviation from the baseline can indicate deception, you know.


Fox Tree, J. E. & Schrock, J.C. (2002). Basic meanings of you know and I mean. Journal of Pragmatics, 3, 727-747.

Gotthelf, B.K. (2014). The lawyer’s guide to Um. Legal Communication & Rhetoric, 11, 1-30.

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