The new polygraph

Reading the chapter about Munchausen’s by proxy syndrome first gave me a stomach ache and then got me thinking about lies and deceit. Sapolsky mentioned that these individuals may be seeking vengeance on the medical field or are desperately calling for attention. I wondered if these individuals were on a “high” for being able to deceive so many people, especially those in the medical field who are considered to be intelligent.

I started looking into research on the neuropsychology of deceit and lies. I found an article examining the neural correlates of different types of deception. They first classified various types of lies on two dimensions; whether they fit into a coherent story and whether they were previously memorized. The researchers made an argument that polygraph methods may confound lie detection. Polygraphs detect increases in measures that reflect increases in arousal, which are then interpreted as fear and guilt. However, fear and guilt may be brought up by other situations besides guilt. Also, if the individual does not feel guilty, there may not be a physiological response. Instead, by looking at the neural correlates, lie detection may become even more accurate.

What the researchers found was that well-rehearsed lies that fit into a coherent story elicit more of a response in the right anterior frontal cortices, while a spontaneous lie activates the anterior cingulate and the posterior visual cortex. In addition, they found that both types of lies showed more activation than telling the truth in the anterior prefrontal cortices, the parahippicampal gyrus, the right precuneus and the left cerebellum. If there is more research into mapping the portrait of a lie in the brain, the criminal justice system may have a new, impossible-to-beat lie detector.

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