Detecting Deception Is Possible, but Not Easy

No one verbal or nonverbal cue can signal deception.

Posted Dec 02, 2017

Selman Amer/123RF
Source: Selman Amer/123RF

Detecting deception remains a difficult task. Researchers have tried, but failed, to identify one verbal or nonverbal cue to detect deception. Detecting deception relies on a variety of cues that have varying degrees of success at predicting deception. To increase the probability of catching a liar, clusters of verbal and nonverbal displays must be identified and compared against a baseline established during a time when people have no reason to lie. Any deviations from the baseline may indicate deception, but that's not always accurate. The best way to detect deception is to compare what people say against a set of known facts; however, this approach may not always be an option. Most people must rely on verbal and nonverbal cues that may signal deception.

The following verbal and nonverbal cues may indicate deception:

  • Liars tend to answer questions that were not asked.
  • Liars tend to answer a question with a question.
  • Liars tend not to make self-corrections to avoid the perception of being unsure about what they are saying.
  • Liars tend to feign memory loss by using statements such as “I don’t remember” and “I don’t recall.”
  • Liars tend to report what they did not do, rather than reporting what they actually did.
  • Liars tend to justify their actions when no justification is necessary.
  • Liars tend to not include emotional feelings in their account of events.
  • Liars tend to report exact times and dates to prove they could not have committed the offense in question.
  • Liars tend to ask for a question to be repeated or clarified.
  • Liars tend to express emotions that are not genuine.
  • Liars tend to use fewer words to describe events or activities.
  • Liars tend to describe weakness and flaws in other people.
  • Liars tend to include fewer details when describing events or activities.
  • Liars tend to use passive language when describing events or activities.   

Conversely:

  • Truthful people often refer to lessons learned from past experiences.
  • Truthful people often include mistakes they made.
  • Truthful people often include dialogue when describing events.
  • Truthful people often report events and activities without exact times and dates.
  • Truthful people often report events and activities without a coherent structure.
  • Truthful people often report unusual or unexpected events that occurred.
  • Truthful people often include sensory information, such as what they smelled when they report events or activities.

Again, caution should be exercised when using these or other verbal and nonverbal cues to pick out a lie, because researchers have yet to identify one verbal or nonverbal cue to detect deception. And more importantly, liars sometimes say and do things that make them look truthful, and truthful people sometimes say and do things that make them look deceptive. Detecting deception is possible, but it is not easy.

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