This question cannot be directly answered in order not to be trapped in the web of unnecessary arguments. Some scholars have actually affirmed that we can all detect lies a little above average level. This doesn’t even exclude law enforcement officers. However, I have come across enforcement agents who did spectacularly well in detecting deception during their active service years. That is why I concluded that rushing to take a side on the question will be too hasty and will dampen the essence of the whole piece.
Recently, people have, unfortunately, relied on machine lie detectors than their own instincts and ability to decode lies. Hassan Ugail, a professor of visual computing at the University of Bradford in a 2014 article notes that “As society becomes more and more dependent on machines to make important decisions, the use of technology for lie detection is becoming increasingly popular. But as much as we would like to rely on technology to give us definitive answers, humans may well always be able to beat the lie detector.” From the foregoing, Ugail is subtly saying that the result of lie detection machine cannot be trusted without the involvement of human effort. Thus, to some extent, we can state that humans can be regarded as lie detectors.
There have been technological advances in recent years but none are foolproof. Most modern systems based on automated facial analysis rely on computer vision technologies to identify and track a face in real time and machine intelligence techniques to make decisions. The system will first look at the expressions a person uses under normal, unstressed conditions and uses those as a baseline when they take the lie detector test. Cues such as asymmetries in facial expressions, shifting gaze and a changed rate of blinking are often associated with strong emotion so if the machine detects unusual variations from the baseline then it is often assumed that the subject is lying (Ugail, 2014). However, some ‘professional’ liars can easily manipulate the workings of the machine and stay glued until it gives them the desired results. In such instances, the contributions of a human being are needed in order to intellectually engage such a person.
However, DePaulo (2013) notes that humans are bad lie detectors. If you ask people directly to tell you how they know when people are lying, they will often give you answers that are way off base. For example, they seem sure that liars won’t look you in the eye, or that they fidget a lot, when research shows that those behaviors are not very useful indicators of whether a person is lying (DePaulo, 2013).
There is a better way to know what behaviors people see as relevant to deception, and that’s to look at the cues they rely on when they make actual judgments of whether a person is lying or telling the truth. In the typical study, people watch a video of people who are lying or telling the truth, and they record their judgments of the truthfulness of each person on the video. Researchers can then correlate the behaviors of the persons on the video with the judgments of the viewers. For example, when people on the video smile a lot, are they more or less likely to be judged as lying?
Such studies tell us which behaviors are judged to be indicative of deception, not which behaviors really are cues to deception. In a comprehensive review article, Hartwig and Bond found a number of cues that are important to people’s judgments of deceptiveness (DePaulo, 2013).
The cues people should use to judge deceptiveness are the ones that really do separate the liars from the truth-tellers. Hartwig and Bond (2011) looked at results for more than 50 cues and found that for about two-thirds of them, people were using the cues they should have been using. When there were discrepancies, people were relying on particular cues more than they should have been. For example, people’s faces really do look a little less pleasant when they are lying than when they are telling the truth, but those who are making judgments about deceptiveness think that facial pleasantness matters more than it really does (DePaulo, 2013).
What never happened is that people, on the average, were using cues the wrong way. They might make too much of an unfriendly person, but they don’t head down the exact wrong track by thinking that people acting friendly are significantly more likely to be lying than people acting unfriendly. They get it that it’s the unfriendly faces that are, on the average, less likely to be trustworthy.
It is also possible to look at the overall pattern of the cues that people used in their deception judgments and compare that to the pattern of cues that people should be using. Again, those analyses showed that people are generally using the right cues. The correlation between the two sets of cues is at least .59. That’s not a perfect relationship but it is pretty good (DePaulo, 2013). So far, it has been reliably established that people, in most cases, actually know the cues to look for in detecting falsehood. The only problem is that in some cases, they hammer on the cues they shouldn’t really have been concerned about or take trivially. I can expertly conclude on this that with the appropriate dose of training, anybody who likes can become an expert in detecting lies. However, the place of instincts and consistent training sessions cannot be downplayed.
Cues to deception are not that useful. There are ways that people act differently when they are lying than when they are telling the truth (that’s what a cue to deception is), but the differences are not all that big or reliable. So, for example, on the average, liars seem more nervous than truth-tellers. But the difference is unimpressive in its size. And, there are lots of exceptions. Sometimes liars do not seem particularly nervous.
If you want to know whether someone is lying, you can’t just sit back and observe their verbal and nonverbal behaviors. If you are a detective, you may need to learn how to ask the kinds of questions that trip up liars, getting them to reveal more than they should. Or you just need to go out and find more reliable evidence (DePaulo, 2013).
References
DePaulo, B (2013). Why Are We So Bad At Detecting Lies? Retrieved from https://www.psychologytoday.com/us/blog/living-single/201305/why-are-we-so-bad-detecting-lies
Hhosie, R (2016). How To Spot A Liar. Retrieved from https://www.independent.co.uk/life-style/how-to-spot-liar-lying-seven-tips-human-detector-darren-stanton-a7487351.html
Ugail, H (2014). Lie Detectors and the Lying Liars who Use Them. Retrieved from https://theconversation.com/lie-detectors-and-the-lying-liars-who-use-them-28167
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