By Christine Hill
On Christmas, my extended family gathered around for a gift exchange, pies, and games. A fairly heated game of “Mafia” ensued, wherein players all try to guess who the secret “killer” in their midst is. The game requires using every resource you can to determine who around you is lying, and who is telling the truth.
I sometimes like to think of myself as an expert at this game. After all, I knew from the get-go that my sister was lying with that all-too-innocent face. She fools most people, but I’ve been the victim of her innocence routine far too often to forget what her poker face really means.
Most of Our Assumptions about Lying Are Wrong
Now, as much as I like to think that I’m an expert at detecting lies, the truth is that I’m wrong just about as often as I’m right. How about you? How do you decide if someone’s lying? Age-old psychology has taught us to look for a few telltale signs; sweating or flushing, avoiding eye contact, fidgeting or covering the mouth.
However, modern research shows that many liars defy all of these signs. In Pamela Meyers’ TED talk “How to Spot a Liar” she says that when we lie, we’re actually more likely to hold our torso and upper body rigid. We may overcompensate with eye contact, holding the other person’s gaze for longer than normal.
Learning facts like these, it’s hard not to start to doubt everything you know about your own ability to perceive the signals of others. After all, being able to spot deception is a basic skill that we rely on all the time, from keeping ourselves from being scammed in business, to being able to tell whether someone we love is at risk for suicide. At the very least, you assume, you’re good at detecting lies that children tell. But you’re probably wrong.
Spotting a Lie Is Harder than We Think
Kang Lee’s TED talk revealed some startling facts. His research found that 30% of kids lie by age 2, and by age 4 and up, it’s almost ubiquitous. Starting so early on, most kids are pros at it by age 7, easily deceiving even those who know them best. Judges, students, officers, and parents alike all had a terrible time determining whether or not a child was lying, with an error margin of 50% (that means there was virtually no difference between a 50/50 guess and our own perception.) Even the parents of the child in question had no idea whether or not their own child was lying.
I think that the reason that lie detection is so difficult is because it has a reflective effect. When we try to determine whether or not someone is lying, we’re relying on our own ability to perceive miniscule social cues into what the other person is actually thinking and feeling. On the other hand, when we lie, we’re relying on our own perception of the other person. We adjust our own reactions to suit what the other person expects of an innocent. Relying on our perceptions of others for both lying and for lie detection, we make it just as likely for us to be fooled as it is for us to fool others.
However, Lee’s talk pointed out an aspect of lying that we often forget: it’s a natural phase of development. In fact, if a child fails to hit the phase of development wherein she realizes that her thoughts are not someone else’s thoughts, and that she has to control and direct what is filtered out to be known by others, she could hit severe developmental problems. This includes lack of communication skills, inability to empathize, and total unawareness of a world outside of her own sphere of perception. Most studies show that in the animal kingdom, the more intelligent a species, the more likely it will lie.
How about Lie Detectors?
Alright then, if humans are so fallible when it comes to lie detection, all we have left is machines, right? The good old lie detector that’s rolled out in cop shows and spy thrillers. We all know how it looks: modules strapped to our arm, temple, chest, and fingertips, monitoring our heartbeat, blood pressure, and temperature. The really sophisticated ones might also monitor pupil dilation and micro-expressions. However, the truth is that polygraphs (as they’re actually called) aren’t very accurate, either. In fact, they might be even more fallible than personal testimony, since one is admissible in a court of law and the other isn’t. That’s right, polygraphs aren’t allowed to be used as evidence in a trial!
Since polygraphs can only measure an individual’s level of arousal when being asked, and answering to, certain questions, it’s very easy to misinterpret. We operate off of the assumption that someone will be calm while answering the truth (or giving answers that they don’t feel guilty about) and anxious when lying, or when responding to questions wherein they are guilty. However, it’s just as likely that an innocent person will show a spike in physical arousal due to anger or anxiety at being accused of something.
The truth is that the polygraph’s main purpose is to scare up a confession. The belief that most people have that it does work can cause someone to be more forthcoming about information that they were previously withholding. Mainly, it’s used as a scare tactic, like this:
Newer monitoring systems may show more promise in revealing truth and lies. Machines that detect the blood flow in vessels beneath the surface of the skin (transdermal optical imaging) have found certain patterns. For example, there’s something called the “Pinnochio effect” wherein the blood flow on the cheeks decreases and instead blood rushes to the nose.
If you want to see what your own ability is for lie-detecting, check out this fun test! BUT, before you decide to start trying to game the system, consider this warm-and-fuzzy truth from a study at the University of Toronto: people who are more trusting are also more likely to be able to spot deception.