In middle school, I used to play those lie detector games with my friends, the ones give you a mild shock if lie. Obviously, a $5 toy doesn’t have scientific accuracy to lie detection. But, I’ve always wondered if there is actually a reliable way to tell if someone is lying beyond the tell-tale signs that behavioral analysts monitor.
When police interrogate criminals, they look for a number of signs to tell if someone is lying. These include repetition of the question, facial expressions, body language, comfort and charm, shifting stories, eye movement and blinking, and phrasing (McGauley, 2015). While these are all proven tactics, they aren’t 100% accurate. There could be outside reasons for a person’s strange behavior. Maybe they’re just nervous, which causes them to mix up their stories and fidget around.
This is why many scientists are working to measure brain activity while a person is lying. This would provide a more scientifically accurate determination of whether a person is lying. Some research involves positioning electrodes on various places around an individual’s scalp to measure the electrical signal on the brain’s surface as the person lies. They commonly ask the participant to choose one of two items and then claim to have neither. This way, they are both telling the truth and lying. The electrodes are flawed however, in that they can’t pinpoint the specific brain area that is activated since it measures such large areas of the brain at once. This is where functional magnetic resonance imaging (fMRI) comes into play.
fMRIs provide more precise reports of where exactly in the brain the activity takes place when someone lies. Lies activate many regions of the brain, but by measuring the blood flow changes that take place in the brain, researchers have been able to generally deduce that there is a spike in prefrontal cortex activity when a person is lying. This is further confirmed by previous conclusions about this area of the brain. The prefrontal cortex is engaged specifically in planning, the development of an individual’s personality, decision-making, and the way someone socializes (Good Therapy, 2013).
Admittedly, many everyday actions stimulate this area of the brain, but this doesn’t mean the procedure is useless. At this point, researchers, using fMRI detection methods, can accurately distinguish lies from the truth about 85% of the time (Curley, 2013). This statistic does not give rise to it’s official use however. The very rare instances where the tests were suggested as evidence in court, the results were quickly suffocated by opposition from neuroscience experts.
There are some obvious flaws that need to be resolved before fMRIs can be used in court cases and elsewhere. All the tests involve manufactured lies. Participants are instructed when and how to lie, and therefore don’t experience the same emotional stress as with a natural lie. Researchers also estimate that even when the lie is genuine, there may be ways to outmaneuver the machines with subtle movements and breathing control. fMRI technology isn’t yet ready to be applied to the real world, but I would guess that we’ll be seeing its use in the near future.