Anatomy of Lying

Anatomy of Lying Is there a "deception center"

By | May 1, 2007

Anatomy of Lying

Is there a "deception center" in the brain?
By Ishani Ganguli

By some estimates, deception evolved in primates 12 million years ago; and as primate species' neocortices grew, so did the frequency of their lies. In humans, learning how to lie, and how to detect lies, is a natural part of childhood development, studies show.

Prevailing psychological models of deception outline three main components of lying: realizing one has information unknown to others, inferring how the recipient will interpret a deceptive act (known as theory of mind), and understanding a personal advantage to the act.

How is that ability carried out in the brain? Neurobiologically speaking, lying is harder work than sticking to the truth: you have to invent the falsehood and suppress the truth while holding both in your working memory. Sean Spence's group at the University of Sheffield has found that responding with a lie (about the day's activities) and takes 200 milliseconds longer on average than responding with the truth.

"FMRI is a messy muddy mixed field...[that requires] extremely well trained people. That's the last kind of technology you want to use in the legal system." -Nancy Kanwisher

While scientists' understanding of the neural processes involved in executing a lie is still sketchy, the few fMRI studies done on deception point to executive brain regions that may be called on to carry out this function: the inferior frontal gyrus, involved in conflict monitoring; the anterior cingulate cortex, associated with mental multi-tasking and rational cognitive functions such as decision-making and reward anticipation; and the prefrontal cortex, called on for cognitively challenging tasks. University of Southern California researchers recently found that pathological liars have more white matter in their prefrontal cortexes than average.

On the No-Lie MRI website, brain regions colored in red are associated with deception and those in blue correspond to truth. But despite the possibility that fMRI may be useful as a predictive tool in lie detection, such depictions are much too simplistic, says New York University's Elizabeth Phelps. Research so far suggests that a complex web of cognitive and affective processes is needed to execute a lie. according to the National Academy of Sciences in its 2003 report on polygraphy: "Identifying areas of brain activation that are specific to deception is not on the horizon, and it is by no means clear that such areas will ever be identified." There's no reason to think lying occupies a unique region in the brain, or is even has a neural pathway specific to the act, adds MIT's Nancy Kanwisher.

Lies come in all kinds of shapes and sizes, and just as memory research has been furthered by distinguishing between different types of memory, says Gabrieli, the next step is "developing a taxonomy of deception...different versions that could map onto some cognitive neuroscience model."

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