Science of lying comes down to timing, but we can’t always trust that

“It seems people believe the delay is used to suppress the instinctive and truthful initial response, while also fabricating a more desirable response,” Dr Wang said.

He said a good example would be where someone asked their friend to give their opinion on their cooking. The difference between immediate praise and a small delay before the same praise would often trigger an “insincere” judgment in the observer.

Dr Wang said most humans were attuned to a range of cues, some obvious and others subtle, which could indicate whether another human was lying to them – from volume and pitch of voice to facial expression and body language.

The researchers wanted to zero in on the time it took to reply to a question as a measure of whether someone was telling a lie or being insincere.

But Dr Wang said pausing was not necessarily a sign of insincerity.

“Perhaps they have to think about the question, give it proper consideration, or perhaps English isn’t their first language,” he said. “There are a number of exceptions to this behaviour, but we don’t naturally account for them in making judgments of sincerity.”

That was a problem, he said, because we were often called on to make judgments about whether someone was lying in formal settings.

He gave the example of people sitting on juries where people might “go with their gut” over whether they believed someone was telling the truth, where they could be mistaken.

“We also see people list sincerity as an important trait for politicians, but a politician taking care to answer a question thoughtfully could unintentionally give an impression of insincerity,” Dr Wang said.

“These examples are why it’s important we’re aware of this unconscious judgment process because it would be unfair to misattribute response time to insincerity.”

Crucially, Dr Wang said many of the study participants were unable to ignore the time it took someone to answer a question, even when asked to by the researchers.

“It’s important to be aware of how we process this information and how sometimes this can lead to misperceptions rather than accurate ones,” he said.

The research has been published in the American Psychological Association’s Journal of Personality and Social Psychology.