Think Someone Might Be Lying to You? Time Will Tell.

New research reveals the mental cost of deception.

Posted Feb 10, 2017

Whether we're a parent, a partner, a police officer, or a politician, we all want to know if the person we're talking to is lying. The cost for believing someone's lies can be high, and there are complementary risks for falsely accusing someone. Thus there's a lot of incentive to discover when a spouse, suspect, child, or anyone else is lying. 

Source: Unsplash/Pixabay

In a new study entitled "Lying Takes Time," the authors focused on the time it takes a person to respond (reaction time, or RT) as a possible indicator of deception. They were following the line of logic that it takes more time to formulate a false response than a true one, which if true should be evident in measures that are highly sensitive to RT.

The authors summarized results from 114 studies that comprised over 3300 subjects. Their analyses revealed a statistically large effect of deception on reaction time, confirming that it takes longer to lie than to tell the truth. 

Several possible explanations were offered for the extra time it takes to deceive. The authors note that lying involves first bringing to mind the truth, which slows the mind's delivery of the lie. "Response conflict" between the truth and the lie (i.e., having to decide which of two answers to give) might further slow the response. Additionally a person may be switching between telling the truth and lying, depending on the cost of the truth—for example, being truthful about where he went but dishonest about what he did there—and task switching is known to take time. 

The authors note an important limitation of their review, that the studies they included all used computerized designs where participants pushed a button rather than verbal responses. This feature made it possible to measure RT much more precisely than is possible with spoken words, though of course it may limit the applicability of their findings. 

Nevertheless, we've probably all detected someone's lie based on their delayed response. For example, if we ask our partner how we look, it only takes a half-second beat before answering to tell us that whatever comes next may not be entirely true. 

The authors note some potentially important applications of this research, including for lie detection purposes in civil or criminal proceedings. Additional work is needed to address the high likelihood of "countermeasures" to conceal the lie, such as simply being sure to answer as quickly as possible.

The next time you're tempted to lie, you might just save yourself some time and tell the truth. 

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Suchotzki, K., Verschuere, B., Van Bockstaele, B., Ben-Shakhar, G., & Crombez, G. (2017). Lying takes time: A meta-analysis on reaction time measure of deception. Psychological Bulletin. doi:10.1037/bul0000087