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Fast Truths and Slow Lies

Responses provided after a pause are seen as less truthful.

Key points

  • Research suggests that responding to questions after a pause makes the responder seem dishonest.
  • Response delays are often seen as the responder suppressing the truthful response and fabricating a lie.
  • People are advised not to rely on response timing when judging truthfulness in high-stakes situations, since response timing could be misleading.
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Falling for a scam call
Source: Mikhail Nilov/Pexels

Historically speaking, believing a lie could lead to costly consequences. For instance, believing a scammer’s call could lead to monetary losses, believing an unfaithful partner’s lie could lead to a loss of time spent on the wrong relationship, and presidents or prime ministers believing the lies of allied nations could suffer the disastrous consequences of military or political betrayal. Generally speaking, not believing the truth, on the other hand, does not seem to result in negative consequences of this magnitude.

The greater risk associated with misses compared to false alarms is perhaps one reason why people tend to be oversensitive when it comes to detecting lies (Haselton & Buss, 2000) . Given this hypervigilance, it might not be surprising that a recent study, which I co-authored, showed that even an inconspicuous cue like a response delay (by as little as 1-2 seconds) could have a significant influence on whether someone is seen as telling the truth ( Ziano & Wang, 2021 ).

As an example, imagine asking a friend why they did not return your missed call, and your friend almost immediately answering: “Sorry, I was in back-to-back meetings all afternoon.” Now imagine the same scenario with one difference: The response was delivered after a slight delay. For most people, the delayed response would be considered less truthful. Indeed, our research findings suggest that longer response times are often attributed to the responder suppressing a raw, instinctive, and truthful response and fabricating a lie ( Ziano & Wang, 2021 ).

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Job interview
Source: Tima Miroshnichenko/Pexels

Are There Exceptions?

Of course, there are some exceptions. Our results suggest that the effect of response delay on perceived insincerity would be much weaker if the response is socially undesirable ( Ziano & Wang, 2021 ). For example, if a job interviewer asked an applicant whether they have had any experience in a similar job and the response is a “no,” regardless of how long it takes the applicant to respond, the interviewers will likely see it as a sincere response. This is understandable since we often need extra time to decorate our answers to make ourselves look good rather than bad!


Interestingly, we found that participants’ reliance on response timing in sincerity judgments was so strong that even when they were told to ignore it in the evaluation process, most participants were unwilling to completely ignore this piece of "evidence" ( Ziano & Wang, 2021 ). This is presumably because people have a deep-rooted intuitive belief that response timing is integral to the sincerity judgment process and a true reflection of the responder’s sincerity.

A Word of Caution

While being able to detect sincerity in others is important for human collaboration and trust, the overreliance on subtle cues such as response timing could be problematic and have significant implications in some high-stakes situations. For instance, people are always judging politicians’ sincerity and deciding who is speaking the truth, but a politician taking care to answer a question thoughtfully could unintentionally give an impression of insincerity.

Another high-stakes example pertains to the legal and courtroom setting—in our study, we showed that people think slow denials are almost as much an indication of guilt as outright admissions of guilt. However, it is important that judges and police officers exercise caution when using response timing as a cue to determine culpability. It would be unfair to misattribute response delays to insincerity when the delay could be the result of other reasons, such as the responder speaking in a non-native language, being nervous, or simply being distracted.

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Police interrogation
Source: Martin Lopez/Pexels

Humans love to take shortcuts and rely on intuition. While this might be an adaptive strategy for conserving mental resources, it might not be the most accurate and certainly not the most responsible way to judge someone’s truthfulness, especially in high-stakes situations. It has been well documented that people, even police officers, are terrible lie detectors—their ability to detect lies accurately is often no different from chance (50 percent accuracy rate), occasionally slightly higher than chance, and sometimes even worse than chance ( Porter et al., 2000 ). When paired together, humans’ overreliance on intuition and tendency to be overconfident can be a recipe for misjudgment with potentially life-changing outcomes, such as an undeserved lifelong prison sentence. So next time you hear someone respond after a slight delay, it might be worthwhile to take a step back and assess the situation in more depth, rather than instantly jumping to a premature conclusion.