New York, Sep 3 (IANS): Ever wondered why some people lie at the drop of a hat while others sacrifice self-interest to tell the truth? It has to do with the functioning of a brain part, says a study.

The dorso-lateral pre-frontal cortex, a brain region known to be critically involved in cognitive control, may play a causal role in enabling honest behaviour, the findings showed.

"The average person usually shows lie aversion," said lead study author Lusha Zhu, a post-doctoral associate at the Virginia Tech Carilion Research Institute in the US.

But people with damage in the dorso-lateral pre-frontal cortex are not as averse to lying as others, the study said.

They are more likely to pick the practical option and are less concerned about the potential cost to self-image.

"People feel good when they are honest and they feel bad when they lie," said Brooks King-Casas, an assistant professor at the Virginia Tech Carilion Research Institute.

"Self-interest and self-image are both powerful factors influencing a person's decision to be honest," King-Casas added.

For the study, researchers compared the decisions of healthy participants with decisions made by participants with damaged dorso-lateral pre-frontal cortices.

The study appeared in the journal Nature Neuroscience.