The efficiency of new lie-detection methods has been doubted by a renowned scholar.
The conventional truth-seeking technologies have been replaced by new brain-based techniques such as functional magnetic resonance imaging (fMRI), and the electroencephalography(EEG), based technology known as Brain Fingerprinting(r).
AdvertisementHowever, University of Illinois professor Melissa Littlefield dismisses today's "forensically sophisticated" polygraphy as dated and unreliable.
"Functional magnetic resonance imaging and Brain Fingerprinting(r) have been hailed as the next, best technologies for lie detection in America, particularly in the context of post-9/11 anxiety," said Littlefield.
"Far from describing the brain and its functions, fMRI and Brain Fingerprinting(r) produce models of the brain that reinforce social notions of deception, truth and deviance," she added.
Littlefield is unconvinced that the new technologies are necessarily superior to the old ones.
She believes that polygraphy may have more in common with the new technologies than many scientists, particularly neuroscientists, would suggest.
"They would argue that traditional polygraphy tests the autonomic nervous system. That's respiration, heart rate, pulse, electrical skin conductance," she said.
Littlefield said using the old-fashioned lie detector, "you're not really getting deception so much as your body's reaction to the stress of deception."
"And they would argue that (with) fMRI, since it's scanning the brain, we're getting closer to the central nervous system, not dealing with the peripheral nervous system.
"We're dealing with what some say is 'the organ of deceit', where the lies are happening, she added.
The old and the new deception-detection tools basically rely on the same three assumptions.
"The first one is that lies are somehow measurable, that you can see them in the body through increased breathing, heart rate ... or by looking at the brain."
In the latter case, she said, "colloquially, people say 'your brain lights up' in the fMRI scanner."
"The second common assumption, she said, is that "when you look at the body and get some kind of information, whether it's pulse rate or blood oxygenation level dependent (BOLD) signals, or whatever it is that each is measuring, that somehow you're able to see the body in action without needing any interpretation."
Finally, she said, "they share this assumption that truth and deception are somehow connected. In deception studies, if you're looking at the polygraph or you're looking at the fMRI, the assumption is that truth is the baseline, the factual, the basic, the natural. And to lie is to add a story on top of the truth."
The article is published in journal Science, Technology and Human Values.