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The Slower You Respond, the Less Truthful You Appear

If you want to pull a fast one on someone, respond quicker to a question.

Key points

  • Not just truthfulness but even perceived guilt and innocence can be significantly impacted by how fast people respond to questions.
  • In general, a faster response seems more sincere, while slower responses are associated with deception.
  • To some extent, we can work against this tendency of linking fast responding to our perception of sincerity.
Mimi Thian/Unsplash
Source: Mimi Thian/Unsplash

Suppose you are a juror listening to testimony from the star witness. The prosecutor asks, “Did you see him holding the murder weapon?” The witness pauses for a few seconds before answering, “Yes.”

Or suppose you have finished dinner. Your significant other says, “Honey, what did you think of that new dessert I made? Did you like it?” You don’t respond immediately, but after a delay, you say that you liked it very much.

Does the pause, the delay in responding, make a difference to how believable someone’s statements come across as? Are faster responses thought to be more sincere and truthful? If so, should we train ourselves to respond more quickly so that others believe what we say?

Intuitively, it seems clear that slower responses would lead to less trust in someone’s sincerity. And now, thanks to 14 new experiments by Ignazio Ziano and Deming Wang, published in the Journal of Personality and Social Psychology, there is strong empirical data to back this up. Here are a couple of highlights from their research.

How the speed of response affects perceptions of truthfulness

In their first study, Ziano and Wang had online participants listen to audio snippets of a question-and-answer exchange. In one of the scenarios, for instance, a person was asked “whether they had stolen money from the company in which they used to work,” followed by the response, “No, I didn’t.” There were different response times used in different conditions of the study, ranging from no delay in responding to 1-, 2-, 3-, 5-, and 10-second delays. For each audio snippet, participants had to rate from 1 to 7 how sincere they thought the person was in answering.

It turned out that the longer the delay in responding, the less sincere the response seemed, until we get to 5 seconds, with little difference at that point between a 5-second delay and a 10-second delay. Overall the point is that slower responses were less believable.

Their next study was even more interesting. This time, participants watched a video of the police interrogating someone accused of workplace theft in the amount of several thousand dollars. Ziano and Wang write that “In the fast condition after the question… 'Did you steal the money?', the actor playing the suspect immediately replied, 'No, I didn’t,' whereas, in the slow condition, the suspect replied after a delay of about 5 seconds.” Here participants rated from 1 to 7 how sincere and truthful the suspect’s statement was, as well as answered yes or no to whether they thought the person was guilty.

The results? The average sincerity rating for the fast responding suspect was 3.84. The average for the slow responding suspect was 2.44. Even more striking were the guilty judgments. The faster suspect was thought to be guilty 40 percent of the time, versus 73 percent of the time for the slower suspect.

In additional studies, Ziano and Wang explored what explains why slower responding would make a difference in these ways. One element that emerged in their findings is thought suppression. It is natural to think that it would be cognitively demanding to suppress a more automatic, truthful reply, so in cases of lying, a slower response is to be expected.

Another element that emerged is answer fabrication. It is also natural to think that making up a bogus response is going to take some time. On the flip side, a fast response would be surprising if thought suppression and answer fabrication were at work.

The relationship between slower responding and lower perceived truthfulness doesn’t hold in every case, however. There are boundary conditions. For instance, Ziano and Wang found that socially undesirable responses do not show as much of a contrast in the ratings of slow versus fast responders. Their main example involved your best friend being asked how your cake tastes and answering, “It’s really bad!” In their study, whether your friend answered fast or slowly didn’t have a big effect on perceived truthfulness.

A question not pursued in this research is whether our perception of delay as a sign of lower sincerity is indeed accurate. Are people, in fact, lying more often in those cases involving slow responses? After all, they might not be, and we could just have a bias that we should work to overcome. This would be an important next step to consider in future studies.

In their final study, Ziano and Wang did consider whether we can overcome our perception of fast responding being linked to sincerity. In other words, when we are in the process of making an assessment of the sincerity or truthfulness of a person’s statement, can we do anything about whether we consider how quickly she responds?

Here they returned to the setup of the police interrogation. This time, in addition to the fast response and the slow (5-second delay) response, some participants received the instructions: “Important: In answering the questions, please do not take into account the speed with which the person replied.” Other participants received no such instructions.

The instructions made a difference. With them, the gap between the sincerity ratings of the slow versus fast responders was much smaller than it would have been otherwise. Also, without instructions, 75 percent of slow responders were thought to be guilty versus only 31 percent of fast responders. But with the instructions, it was 60 percent versus 41 percent. In other words, the gap shrank but was clearly not eliminated entirely.

Key takeaways

So the upshot is that we often penalize people for responding slower, although there are also specific situations where we don’t do this as much. It remains to be seen whether we are right to be doing so or whether this is an unreliable bias on our part. And if it is something we need to curb or refrain from doing, then it looks like we do have some control over our tendencies in this area, but maybe not complete control. We could need some additional help.

For now, it appears that if you want to pull a fast one on someone, the faster you respond, the more likely it is that you will succeed.


Ziano, I., & Wang, D. (2021). Slow lies: Response delays promote perceptions of insincerity. Journal of Personality and Social Psychology, 120(6), 1457–1479.

An earlier version of this article appeared in Forbes here.

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