When answering a question, your silence might say more than your words. A new psychology study has found pausing before replying, even for just a few seconds, can make you seem more insincere or dishonest.

Even when listeners are told to ignore your pauses, they're still more likely to judge a slower response as more of a 'slow lie'.

That perception of dishonesty might not be too inaccurate, either. Numerous studies in the lab and in real life suggest people are slower to respond when they are not being truthful, possibly because it takes more mental work to inhibit a truthful response or fabricate an alternative.

What's been less clear is how well our lies have been fooling people. Some studies suggest delayed answers come across as insincere to the listener. Others find no relationship between the two, and still more have found the opposite: That a bit of hesitation increases our perceptions of sincerity.

These findings are inconsistent and confusing. They are also mostly based on correlations. Even the few studies that have actually looked at causal relationships often didn't consider confounding factors that could also give away a liar or an insincere speaker.

The new research seeks to remedy some of those limitations by examining thousands of people under a variety of conditions. Together, it involves more than 7,500 individuals from the United States, the United Kingdom, and France in a total of 14 experiments.

Each of these tests was designed to determine how participants rated slow responses in two different contexts. The first response was based on whether or not someone liked a cake that a friend had made. The second response was about a crime that had occurred in the workplace.

Participants either listened to these questions and answers as an audio snippet, watched a video, or read an account. They then rated the sincerity of the actor giving the response.

On the whole, the authors found an immediate response was perceived as more sincere, while a delayed response, even a delay as brief as two seconds, was seen as more insincere.

"Evaluating other people's sincerity is a ubiquitous and important part of social interactions," says consumer behaviour researcher Ignazio Ziano at the Grenoble Ecole de Management in France.

"Our research shows that response speed is an important cue on which people base their sincerity inferences."

The findings were consistent across cultures and contexts, although some situations had smaller effects. This suggests people have a "sophisticated understanding" of what response speed means in different contexts, the authors say.

In the cake scenario, for instance, where one of the answers was considered socially insulting ("No, I don't like your cake"), response speed didn't matter to as much of an extent.

This suggests questions like 'Do you like my cake?' have an expected response. A shorter pause is, therefore, likely to be dismissed by the listener.

On the other hand, in a more serious setting, where someone was asked about stealing something in the workplace, hesitation was found to imply deception or guilt to a much quicker degree. In other words, there was less room for hesitancy to be excused.

That said, even in a criminal setting, there were some subtle differences in context. If a slower response was warranted – for instance, if a crime had happened many years ago and would take some mental effort to recall – the speed of someone's response was less important to their perceived sincerity.

In this case, participants didn't think the slow response indicated suppression of the truth, merely that the person was hesitating to find the truth.

These findings have important implications in a variety of social interactions, but one of the most obvious is in our understanding of jury reactions to court testimony.

"It would be unfair for the responder, such as a crime suspect, if the response delay was misattributed to thought suppression or answer fabrication when it was in fact caused by a different factor, such as simply being distracted or thoughtful," explains Ziano.

Unfortunately, even when participants were instructed to ignore the response delays in one of the experiments, it only reduced their perception of insincerity; it did not completely remove it.

In general, however, Ziano says their study shows whenever there is a question that requires an answer, such as in a job interview, quick responses look more sincere.

The study was published in the Journal of Personality and Social Psychology.