By Dominic Ali
A University of Toronto report based on two neural imaging studies that monitored brain activity has found a reward given for telling the truth gives people greater satisfaction than the same reward given for deceit.
These studies were published recently in the neuroscience journals Neuropsychologia and NeuroImage.
"Our findings together show that people typically find truth-telling to be more rewarding than lying in different types of deceptive situations," said Professor Kang Lee, whose research is funded in part by the Social Sciences and Humanities Research Council.
The findings are based on two studies of Chinese participants using a new neuroimaging method called near-infrared spectroscopy. The studies are among the first to address the question of whether lying makes people feel better or worse than telling the truth.
The studies explored two different types of deception. In first-order deception, the recipient does not know the deceiver is lying. In second-order deception, the deceivers are fully aware that the recipient knows their intention, such as bluffing in poker.
The researchers were surprised to find that a liar's cortical reward system was more active when a reward was gained through truth-telling than lying. This was true in both types of deception.
Researchers also found that in both types of deception, telling a lie produced greater brain activations than telling the truth in the frontal lobe, suggesting lying is cognitively more taxing than truth-telling and uses more neural resources.
The researchers hope this study will advance understanding of the neural mechanisms underlying lying, a ubiquitous and frequent human behaviour, and help to diagnose pathological liars who may have different neural responses when lying or telling the truth.
The team was composed of researchers from Zhejiang Normal University, China; East China Normal University, China; Beijing Jiaotong University, China; and the University of Toronto.
Dominic Ali is a writer with University Relations at the University of Toronto.