University of Tartu cognitive and law psychology professor Talis Bachmann and doctoral candidate and lector at the Estonian Academy of Security Sciences Inga Karton carried out experiments to determine whether it is possible to affect the likelihood of lying by stimulating the human brain.
Prefrontal Cortex: The dorsolateral prefrontal cortex in the brain (shown in purple) is thought to be intimately involved with the process of decision-making. Photo: Wikimedia Commons
The dorsolateral prefrontal cortex (a part of the brain neocortex) regulates short-term memory, plays an important role in directing intellectual processes, and also takes part in morality-related decisions. This region has also been shown to play a significant role in several deceptive activities, including cheating and lying.
The experiment was carried out on 16 volunteers who were shown colourful circles on a computer screen and given the task of reporting the circle’s colour. The experiment guidelines gave them a chance to choose freely between telling the truth or lying without any risk.
During the experiment, the subjects’ dorsolateral prefrontal cortex was affected by a strong magnetic field using transcranial magnetic stimulation, a technology that makes it possible to channel electricity directly into the brain. The process is painless and subjects only reported a mild tickling sensation.
When the magnetic field was affecting the dorsolateral prefrontal cortex of the left hemisphere, subjects tended to lie more. Stimulating the same region in the right hemisphere increased the likelihood of telling the truth.
Longer stories on the same subject appeared in the Popular Science magazine and in the Guardian.
Karton I, & Bachmann T (2011). Effect of prefrontal transcranial magnetic stimulation on spontaneous truth-telling. Behavioural brain research, 225 (1), 209-14 PMID: 21807030
