Researching into the cognitive process involved with honesty researchers say that truthfulness depends more on absence of temptation than active resistance to temptation.

Harvard University psychologists, Assistant Professor Joshua Greene and graduate student Joe Paxton, the duo that led the study, have revealed that they used neuroimaging to look at the brain activity of people given the chance to gain money dishonestly by lying, and found that honest people showed no additional neural activity when telling the truth.

The researchers say that that observation implied that extra cognitive processes were not necessary to choose honesty.

However, the researchers also found that individuals who behaved dishonestly, even when telling the truth, showed additional activity in brain regions that involve control and attention.

"Being honest is not so much a matter of exercising willpower as it is being disposed to behave honestly in a more effortless kind of way. This may not be true for all situations, but it seems to be true for at least this situation," says Greene.

The researchers say that they carried out the study to test two theories about the nature of honesty - the "Will" theory, in which honesty results from the active resistance of temptation, and the "Grace" theory in which honesty is a product of lack of temptation.

Writing about their findings in the journal Proceedings of the National Academy of Sciences, they have suggested that the "Grace" theory is true, because the honest participants did not show any additional neural activity when telling the truth.