Slow responses more likely to be perceived as lies, study finds

The longer a person takes to respond to a question the more likely it is they will be perceived as lying – whether it is a question about a crime or a friend’s baking skills.

Beyond volume, tenor and the pitch of an answer, response time also appears to play a role in the way people perceive the sincerity of answers, psychologists have found.

Slower responses were perceived as less sincere than faster, “raw” ones because people believed that response speeds could reflect the speaker taking that little bit longer to fabricate an untruthful answer, according to analysis of 14 experiments involving 7,500 individuals from the US, the UK and France.

A pause before replying to a question, even for just a few seconds, prompted the listener to perceive the answer as less sincere and credible than if the speaker had replied immediately.

Research participants either listened to an audio snippet, viewed a video or read an account of a person responding to a simple question. In each context, the response time varied from immediate to a 10-second delay – participants then rated the sincerity of the response on a sliding scale.

For example, in one experiment involving 562 participants, people watched videos of a police interrogation in which an actor was accused of stealing money from their workplace. In the “fast” video, the suspect immediately denied the allegation, while in the “slow” video the suspect responded after a delay of about five seconds. Overall, the participants considered the faster actor guilty 40% of the time, but the slower actor guilty 73% of the time.

This effect was “pervasive and robust” across all the experiments, said the study’s lead author, Ignazio Ziano, an assistant professor at Grenoble Ecole de Management, France. “It’s only after a lot of experiments that we identified situations in which this effect is smaller.”

For instance, when the answer was socially undesirable, response time did not seem to matter, he said. “So if they accuse you of having stolen the money, and you say yes … that’s a socially undesirable response – it has a cost for you so it’s going to be interpreted as something that is sincere.”

The researchers, writing in the Journal of Personality and Social Psychology, also found that if people thought a slower response was due to mental effort (for instance, having to think back if you had stolen candy a decade ago), the response speed was less relevant.

Other factors such as nervousness or being thoughtful, could also explain a delayed response, they cautioned.

Overall, these findings could have implications for many scenarios – such as job interviews and court trials – where people are entrusted to make judgments on sincerity.

“It’s true that, on average, ‘liars’ are slower than ‘truth-tellers’,” said Ziano. “But ‘on average’ in court proceedings is not enough. We need to be much more careful, especially when lives and years of life are at stake.”