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MLA Full: "The Science of Lying." YouTube, uploaded by SciShow, 1 July 2012,
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APA Full: SciShow. (2012, July 1). The Science of Lying [Video]. YouTube.
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Chicago Full: SciShow, "The Science of Lying.", July 1, 2012, YouTube, 08:50,
Hank gets into the dirty details behind our lying ways - how such behavior evolved, how pathological liars are different from the rest of us, and how scientists are getting better at spotting lies in many situations.

Hosted by: Hank Green
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 Introduction (00:00)

Hey y'all. Time for two truths and a lie. I'm going to tell you three things about myself. Uh, and you’re going to have to pick out the one that is not true. Ready? OK.
Number one: I have a machine at home that transforms plain water into carbonated water. Two: I’m really bad at the card game Set. Or three: Michael Jackson is my aunt. Was it that obvious?

Off-screen Voice: Yeah.

God, I’m so bad at game.

[Lie to Me style intro]

 Behavior (00:33)

Lying. We do it a lot, and we’re a lot better at it than you’d like to think. Like, I’m not stupid; I could have totally made up a better lie than “Michael Jackson is my aunt.” But, check it out, the fact that I appeared to be terrible at lying was in fact a lie.

In a ten-minute conversation with a stranger, we humans will tell an average of three lies. Researchers who study lying say that the subjects of these lying studies rarely even realize that they’re doing it.

But why? What purpose does lying actually serve?

Well, to put human deception into perspective, it’s worth pointing out that humans aren’t the only fibbers in nature. My favorite anecdotal example of non-human lying: Koko the Gorilla, who was taught sign language back in the 1970’s, once actually blamed her pet kitten for ripping a sink out of the wall in her room. Bad, bad All Ball.

 Purpose (01:21)

So yeah. Lying is nothing new in nature But why do humans specifically do so much of it?

Well as I’ve mentioned here before on SciShow, humans are first and foremost social animals. We've got really super-huge brains, and that’s mainly because we need them for all the interacting we’re always doing. For humans, successful social interaction is key to success in much of our lives.

So it’s clear that lying is a great way of keeping elaborate social structures running smoothly while looking out for number one. For instance, if you can keep your social group happy, you’re going to reap all kind of benefits like food, higher social standing, more and better sexual partners. And, you know, you don’t make friends and influence people going around and saying things like “Actually, that loincloth does make your butt look big,” or “Hey, uh, I have been having sex with your brother while you’re out hunting mastodons, so little Glurgh over there is probably your cave nephew.”

So the ability to lie and to detect a lie became pretty important to early humans because lying is actually not very easy for a brain to do. And it actually caused a bit of an evolutionary arms race.

 Societal Intervention (02:21)

So people started to get better and better at lying, and better liars got better stuff while hopefully remaining in good standing with their communities. By the same token, those who were better at detecting lies were cheated on by their mates and screwed over in camel trades a lot less often. So yes, now we’ve evolved to be good liars and also good at spotting bad liars.

But as societies became more sophisticated, folks were like, “OK, OK, enough with the lying!” Because there are lots of advantages to living in tight-knit communities and structured societies, but you can’t really have them when you don’t know for sure if the kids you’re raising are yours and if the camel you just bought has ever been in an accident or whatever.

So a society in which bold-face lying goes completely unchecked leads to total anarchy! So organized societies started putting the hammer down. Religious systems began to drive home the point that God rewards and cares for the truthful and punishes liars. So if you could survive being thrown into the bog and tied up with a sack of hammers, God was on your side, and you were telling the truth. If not, you were obviously lying. Oh, medieval European judicial system, how I love you.

Even now, in modern times, there are laws that prohibit lying and override even our rights to free speech. For instance, you go to jail for lying in a court of law or for lying about having received a Medal of Honor for service in the armed forces. Don’t do that. Also, ‘cause you’re not an evil... Why would someone do that?

 Lying: Human Development (03:45)

So, lying. It’s not OK. But we’re all so good at it, and our brains want to do it. And we start lying really early; some researchers say as early as six months old. I mean, you’ve seen a baby fake cry, right? It’s very obvious. Like they’re crying [mimics fake crying], then they like check to see if anybody’s coming over to sympathize, and then they’re like “Oh, I’m going to keep crying then.”

Scientists think this is the time when babies are actually learning how to be better liars. By the time the kid is in college, they’re lying to their mom about once in every five interactions. And actually, that seems, that seems low to me. I would say five out of five for my college experience. Kids these days. Actually, kids every day.

By the time we’re adults, we’ve gotten so very good at lying that we’re actually able to do it to ourselves very effectively. The trick to lying to yourself is in the holding of two pieces of conflicting information in your head at the same time and paying attention to one while ignoring the other.

 Pathological Liars (04:39)

People who are good liars can hold a bunch of conflicting information in their heads all at once and keep track of it all. Take pathological liars, people who habitually and compulsively lie, cheat, and manipulate other people.

The thing about pathological liars is that they're super good at self-deception. At the moment they’re telling it, they whole-heartedly believe their own lie. Interestingly enough, there is an actual difference between the brain of a normal person and the brain of a pathological liar.

That difference is in the very front of the brain, in a place called the prefrontal cortex. Most neuroscience studies focus on the gray matter of the brain – that’s the material that actually processes information. However, nearly half of our brain is made up of what’s called white matter, which is composed of connective tissues that carry electrical signals from one group of neurons to another. So gray matter is where all the processing happens, and white matter connects the different parts of the brain.

In a study at the University of Southern California, researchers found that pathological liars have about twenty-five percent more white matter in their prefrontal cortex than the rest of us, suggesting that pathological liars can make a bunch of connections in their brain really fast. And that lets them keep all the information in order that they need to sustain the lie, also to read the person that they’re lying to, suppress their emotions, and probably believe what they’re saying on top of it all.

So, why haven’t pathological liars taken over the world? I mean, they seem to be the next step in human evolution.

While pathological liars have a surplus of white matter, they also have around fourteen percent less gray matter than other people. And gray matter is where all the critical thinking happens. So the white matter is all like, “I’m gonna tell Jim I used to be a fighter pilot!” And the gray matter is all, “I could tell Jim I used to be a fighter pilot, but I probably shouldn’t because that would jeopardize my relationship with Tammy.” So extreme liars have a really hard time maintaining relationships and holding down jobs because, after a while, everybody realizes that they're full of crap and they get dumped or fired, which is not ideal for the person. It’s great for everyone else.

 Lie Detection (06:29)

But if there are these super liars out there, how do we know when if we’re being lied to? And I mean, lie detectors might be able to pick up signals like change in the liar’s voice, or increased heart rate, or sweating, all stuff that we do when we’re fibbing outright. But a really good liar might not display any of those symptoms.

Well, no matter how good of a liar you are, the fact that you are lying will often leak out, both through your body language and through your word choices. Let’s look at a sample sentence: Believe me, I was not the one who farted and evacuated that movie theater.

So do you believe me? Probably not because I did three things in that sentence that made you totally certain that I was, in fact, the person who made them evacuate the movie theater. To wit!

One: I said “believe me.” Liars will always say that, or “to be totally honest.” Or Richard Nixon’s favorite: “in all candor.” Two: I all of a sudden stopped using contractions. Liars often use more formal language to deny something that they’ve actually done. And three: I said “that movie theater” instead of “the movie theater.” I was trying to distance myself from the whole situation.

We think of liars as being fidgety, but we actually tend to freeze our upper bodies when we lie. We make more, not less, eye contact; maybe a little too much to over-compensate for telling a fib. Liars will also do things like shake their heads while saying yes and smile when they’re done telling a story, even if it’s a terrible one.

 Conclusion (07:45)

All of this stuff, the reading of what we leak through our words and bodies, is actually the future of lie detection. Training law enforcement officers to read potential criminals to catch them in the act of lying. Of course, they’re always coming up with new kinds of gadgets all the time, too: eye trackers, MRI brain scanners that are going to replace the old lie detector tests. Maybe I’ll tell my two truths and a lie in a brain scanner and see how it does.

Off-screen Voice: I’m pretty sure we all know how that’s going to turn out.

Yeah, you’re right. I’m a terrible liar. Or am I? [cackles]

 Credits (08:16)

Thank you for watching this Infusion. All of the facts contained within are not lies, we promise! But if you want to check, there are citations in the description. Of course, because we’re scientists here.

If you have ideas for future episodes of Infusions, you can leave those in the comments or connect with us on Facebook or Twitter. Also questions, we’ll be happy to answer those as well. We’ll see you next time.