【fMRI测谎:让谎言无所遁形】

【fMRI测谎:让谎言无所遁形】很多时候,手心出汗和心跳加快可能会帮助我们辨别一个骗子,但其实最本质的东西在于大脑。fMRI 是一种更为有效的方法,通过扫描大脑决策区建立图谱,由专家进行判断。Daniel D. Langleben,MD教授称,他们相信世界上没有独一无二的谎言,人类在撒谎时大脑活动有固定的规律。

The brain scan that tell if you're lying: Researchers say fMRI scans are now better than a polygraph at working out if someone is telling the truth

By CHEYENNE MACDONALD

Sweaty palms and a racing heartbeat might help you to spot a liar, but the most tell-tale evidence lies in the brain.

For the first time, researchers have conducted a controlled comparison of fMRI scans and polygraph testing in lie detection.

The study revealed fMRI is a far more effective method, as it picks up on the activation of decision-making areas in the brain when a person tells a lie, allowing it to identify deception up to 90 percent of the time.

Researchers from the Perelman School of Medicine at the University of Pennsylvania used a standardized ‘concealed information’ test to compare the two methods.

Polygraph measures a person’s electrical skin conductivity, heart rate, and respiration during questioning, and has been in use for over 50 years.

But, it is known to be inconsistent in its abilities – studies have found polygraphs to range everywhere from 100 percent accuracy to ‘chance’ at best.3A11DD1800000578-3906532-FMRI_picks_up_on_the_activation_of_decision_making_areas_in_the_-m-53_1478284997615

Functional magnetic resonance imaging (fMRI), on the other hand, looks at the activity in the brain.

‘Polygraph measures reflect complex activity of the peripheral nervous system that is reduced to only a few parameters, while fMRI is looking at thousands of brain clusters with higher resolution in both space and time,’ said the study’s lead author, Daniel D. Langleben, MD, a professor of Psychiatry.

‘While neither type of activity is unique to lying, we expected brain activity to be a more specific marker, and this is what I believe we found.’

In the study, 28 participants were given the ‘Concealed Information Test’ (CIT), which uses carefully constructed questions, some with known answers, to determine if a person has specific knowledge.

Each participant was asked to secretly write down a number between three and eight, and they were then given the CIT while hooked to a polygraph and while lying inside an MRI scanner.3A11DD5400000578-3906532-image-a-54_1478285470352

For the test, they were also asked to answer ‘no’ to each question, ensuring that one of the responses would be a lie.

These responses were then evaluated separately by three polygraph and three neuroimaging experts.

The researchers found that fMRI scans were far more likely to correctly reveal a liar.

Overall, the neuroscience experts without any prior experience in lie detection were 24 percent more likely to spot deception than the professional polygraph examiners.

The researchers point to the example of one participant who picked the number seven.

When asked about this number, the polygraph examiners identified the number six as the lie, due to high peaks after the participant was asked the same question several times in a row.

But, the fMRI scans clearly indicated increased activity when the participant was asked about the number seven.

Along with this, the researchers also found that in 17 cases when both the polygraph and the fMRI identified the same number, they were 100 percent correct.

The researchers say the findings suggest these two methods can be complementary for more accurate predictions, but further studies will be needed to put this to the test.

‘While the jury remains out on whether fMRI will ever become a forensic tool,’ Langleben said, ‘these data certainly justify further investigation of its potential.’

http://www.dailymail.co.uk/sciencetech/article-3906532/The-brain-scan-tell-lying-Researchers-say-fMRI-scans-better-polygraph-working-telling-truth.html


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