The Jordan Harbinger Show - 1272: Left-Handedness | Skeptical Sunday

Episode Date: January 18, 2026

Scissors, spiral notebooks, cultural taboos — lefties have it rough. Jessica Wynn explores why 10% of us are southpaws here on Skeptical Sunday.Welcome to Skeptical Sunday, a special edition of The Jordan Harbinger Show where Jordan and a guest break down a topic that you may have never thought about, open things up, and debunk common misconceptions. This time around, we’re joined by writer and researcher Jessica Wynn!Full show notes and resources can be found here: jordanharbinger.com/1272On This Week's Skeptical Sunday:Left-handedness isn't controlled by a single gene — it's a cocktail of genetics, prenatal environment, and random brain development. The rare gene variant TUBB4B shows up three times more often in lefties, but even identical twins sharing 100% of their DNA can have different dominant hands.Your handedness was essentially decided before you were born. Ultrasound studies reveal fetuses showing consistent hand preferences by 18 weeks — those who suck their left thumb in the womb typically become left-handed. Your fetal position and which direction you turned your head may have sealed your southpaw fate.Left-handers possess a larger corpus callosum — the neural bridge connecting both brain hemispheres — enabling faster communication between the two sides. This biological quirk gives lefties advantages in multitasking, creative problem-solving, and activities requiring rapid information processing like video gameCultural conditioning has historically punished left-handedness, associating it with everything from uncleanliness to witchcraft. Schools once forced children to switch hands, and in some cultures today, using your left hand for eating remains taboo — a lingering echo of pre-toilet paper hygiene practices.Celebrate your brain's beautiful asymmetry — whether you're a lefty or righty. Try using your non-dominant hand for everyday tasks on August 13th (International Left-Handers Day) to appreciate how deeply ingrained handedness really is. It's a humbling reminder of how wonderfully weird human development can be.Connect with Jordan on Twitter, Instagram, and YouTube. If you have something you'd like us to tackle here on Skeptical Sunday, drop Jordan a line at [e-mail] and let him know!Connect with Jessica Wynn at Instagram and Threads, and subscribe to her newsletters: Between the Lines and Where the Shadows Linger!And if you're still game to support us, please leave a review here — even one sentence helps! Sign up for Six-Minute Networking — our free networking and relationship development mini course — at jordanharbinger.com/course!Subscribe to our once-a-week Wee Bit Wiser newsletter today and start filling your Wednesdays with wisdom!Do you even Reddit, bro? Join us at r/JordanHarbinger!This Episode Is Brought To You By Our Fine Sponsors: Quiltmind: Email [e-mail] to get started or visit quiltmind.com for more infoMomentous: 20% off first order: livemomentous.com, code JORDAN20Homes.com: Find your home: homes.comProgressive Insurance: Free online quote: progressive.comSee Privacy Policy at https://art19.com/privacy and California Privacy Notice at https://art19.com/privacy#do-not-sell-my-info.

Welcome to Skeptical Sunday. I'm your host, Jordan Harbinger. Today I'm here with Skeptical Sunday co-host, writer and researcher Jessica Wynn. On the Jordan Harbinger show, we decode the stories, secrets and skills of the world's most fascinating people and turn their wisdom into practical advice that you can use to impact your own life and those around you. Our mission is to help you become a better informed, more critical thinker. And during the week, we have long-form conversations with the variety of amazing folks, from spies to CEOs, athletes, authors, thinkers, performers. On Sundays, though, it's Skeptical Sunday, a rotating, guest co-host and I will break down a topic you may have never thought about and debunk common misconceptions about that topic. Topics like astrology, recycling, chem trails, GMOs, GMOs, toothpaste, crystal healing, and more. And if you're new to the show or you want to tell your friends about the show, I suggest our episode starter packs. These are collections of our favorite episodes on persuasion, negotiation, psychology, disinformation, junk science, crime and cults, and more. That'll help new listeners get a taste of everything we do here on the show. Just visit Jordan Harbinger.com slash start or search for us in

your Spotify app to get started. Today on the show, it's possible you know someone who's left-handed, or maybe you're one of those people who insists on announcing it every time you pick up a pen. Aside from the fact that lefties use their left-hand to write, play sports, do everyday tasks, you probably don't know much else about left-handed folks. As a lefty myself, I'm also curious what makes me a lefty in the first place. What gives us our handedness? To get to the right or left side of things is writer and researcher Jessica Wynn. So Jess, I'm left-handed, I'm just going to cut to the chase and assume that makes me superior to most other people, correct? I think so, but you are in good company.

Okay. Lady Gaga, Obama, Jimmy Hendricks, me. So you're on the left side of things. Nice. But honestly, it can be kind of a drag, scissors. They don't work. They don't fit. Spiral notebooks are some kind of medieval torture device because I'm in and then I'm

dragging ink across the page while getting a metal spring print on my wrist for six hours a day. You know the drill. Oh, yeah. It's the worst. I know. I spent my school days with a permanent ink stain on my left hand. I've battled every school supply and utensil ever made. But we can't help it. And there is actual science behind all this. Okay. So what is going on here? Why are some people left handed? Is it genetics? Is it witchcraft? What's going on? Well, maybe a little of both. Handedness is this weird mix of genetics, environment, and random quirks in brain development. As our understanding of, genetics unfolds, we are learning more about what causes traits like-handedness. What we do know today is that there's no single left-handed gene. It's more like a cocktail of small influences all mixing together.

Okay, but it's not that common. Most people are right-handed. It's not 50-50. Oh, no, yeah. Lefties are rare. Only about 10% of the world's population is left-handed. 10%. That's, what is it, like 800 plus million people holding scissors incorrectly. Right. And get this. Statistics also show men are slightly more likely to be left-handed than women. If you're a man, you have about a 12% chance. Women, 10%. Why that is is still a complete unknown. So even hand dominance is a gendered issue. Of course it is. I demand equality, Jessica. Yeah. I mean, it's not a huge difference, but statistically significant. Okay, so really, I'm a demographic unicorn, you know, left-handed, Jewish and ridiculously good-looking. There's a lot of Venn diagram. Go on.

Yes, anyway, anyway, continue. Yeah, I mean, there's some other interesting patterns, too. Studies show children born to mothers over 40 are more likely to be left-handed. So mom decides. That's a lot of power for mom. My mom had me not quite at 40, but I think she was 37, 38, so I don't know if that counts. Yeah, that could have been a factor for sure. Yeah, it could have been a factor.

Do we know why this is the case? I mean, again, that's a lot of power sort of just for mom, but I don't know. The baby's baking in there, so. In the case of mom's age, there's a scientific theory that points to prenatal hormones and how the brain develops in the womb. That influences which side of the brain becomes dominant, and that determines a bunch of stuff, including our handedness. So for whatever reason, people born to older moms, they just swing left.

I never thought about handedness starting in the womb. I thought it was a school thing. Okay. Interesting. Right. Yeah. So the brain's asymmetry, meaning how the left and right hemispheres develop, is set really early on. Most people's language centers end up on the left hemisphere, which controls the right hand. But for lefties, it's often reversed or it can be shared between both sides.

So our brains literally pick a side in utero, a little fetal game of chance. Yeah. Yes. Yeah. It's all decided before we ever pick up a crayon. And in the 1990s, researchers identified a rare gene variant that they think plays the biggest role in the asymmetric left-right brain split. It's called Tub 4B, T-U-B-B-4B, and is present in every human, but in left-handed people, it's mutated. T-U-B-B-4B sounds like a Star Wars droid. Yeah, it is the droid they were looking for, right? So Tug4B is short for tubulin beta 4B Class 4B. It's a gene connected to microtubules, tiny structures in your cells that act like scaffolding.

So these microtubules shape how neurons grow and connect and keep our cells structured, organized, and help them divide and move. Wow. So does being left-handed mean something is wrong with our microtubules or our T-U-B-4B? In a roundabout way, yeah, sort of. These microtubules are crucial and associated with a lot of biological functions. The researchers have found that some mutations of the tub 4B gene mess with microtubules and lead to hearing loss, vision problems, even infertility. So microtubules influence the cilia, those little hair-like organelles that move fluid around developing tissue. And when the flow of that fluid is uneven, it creates the left-right split in the brain.

And that determines whether I bat with my left or right hand. Wow. It's definitely a part of it, yeah. So the job of these microscopic little guys is to determine how the brain organizes itself. They're like our cells own Martha Stort. You just think that little tiny little thing and just sets up my whole life. I guess it's the sort of the stoned version of Martha Stewart though. Yeah, yeah.

They're in an altered state for sure. These rare tub 4B variants don't explain everything, though. Previous studies have found several genes that seem to be tied to left-handedness. A breakthrough study published in Nature Communications Journal looked at over 350,000 people, 38,000 of them were lefties and over 300,000 righties, they found that this rare variant showed up about three times more often in left-handers. So this gene doesn't cause left-handedness. It just shows up at the party every time left-handedness happens. Right. And at this point, it's correlation. It's not the cause.

In fact, identical twins who share all the same DNA can still have different dominant hands. So twins are always particularly interesting case studies, and about 20% of twins are left-handed, higher than in single births. Crazy. So two people can share a womb, share a genome, look almost exactly the same, and they still can't sit next to each other at dinner without bumping elbows. Yeah, right. That's how we know the environment and random development patterns matter just as much. genes are only part of the story. So research shows that left-handedness comes down to tiny random differences in our position in the womb. So what? How you chill in the womb is an indicator of your dominant hand for life? Like a fetus is just vibing and then somehow that predicts if you'll be left-handed.

That seems so random, but I guess that's nature. Yeah, that's how it is. Even your position in the womb. So whether you were facing left or right plays a role. It's like prenatal feng shui. Yeah, doctor, why is my baby, left-handed. Well, his fetus roommate was hogging the right side of the uterus. So the rest of his life, he's going to be unable to write with a pencil without making a mess. That's just,

that's remarkable. Yeah, I mean, that's not far off. Ultrasound studies show fetuses start using consistent hand movements around 18 weeks. Those who suck their right thumb in the womb, usually grow up right-handed. Those who go for the left thumb, left-handed. It sticks. I didn't even realize fetuses suck their thumb in the womb. Wow. Wow. I know. They do. At early, too, I thought there was more, I guess I thought there was more of a nature versus nurture balance that influenced things later on. Well, we just see it really early. But that's the big question. Nature and nurture are both going on in the womb, too.

So the brain starts picking sides before you even have thumbs, actually. Scientists have been chasing the genetic side of this for decades. I knew I was a genetic marvel. It's like a cosmic coin toss that decides how a microscopic current in the womb flows. and now I can't use a freaking vegetable peeler. Thanks. I mean, genetics is definitely a part of it, but it's not the only thing pulling the strings.

It's many small genetic effects, plus the prenatal environment, and then some good old-fashioned randomness. Okay, so a bunch of stuff is working together to nudge development in a certain direction. But is it hereditary? Like, if two left-handed people have a baby, are they kind of guaranteed to have a left-handed kid or no?

No, not at all. Children of left-handed parents are more likely to be left-handed, but the probability is still pretty low, and most children still turn out right-handed. So Heredity has a genetic component, so it does raise the odds, but it doesn't seal the deal. Like, are your kids left-handed? No, I think, well, so far they're both right-handed, and I'm kind of the lone lefty island in my own house. In fact, the only other left-handed person in my entire family is my mom's uncle. Wow.

Not really something that shows up elsewhere in the household. Yeah, it's rare. I mean, do they ever try to copy the way you do things, like a little left-handed mimic phase or anything? Maybe, but I've never noticed. I have seen the reverse, though, in other people. Beatles fans are trying to mirror, is it Paul McCartney on the base? Total nightmare. He's left-handed.

And a lot of his bases are truly lefty builds. And you can't just sort of flip that thing around and hope for the best. But that's more like adults being ignorant, not knowing how to play the guitar. My kids, I don't think, have even noticed that I'm left-handed, honestly. Yeah, they probably don't. have that concept yet because it is just a natural dominant thing we do. And it would be a significant challenge to as an adult try and use a less dominant hand because handanness is decided long before anyone picks up an instrument. And studies show that in the womb, fetuses start showing

little quirks like a head turning bias, meaning some turn to the right more often, which means they get more sensory feedback from that side, that feedback reinforces right-hand use later on, and vice versa. Left turners end up left-handed. That is remarkable that it's determined so early. I can't really speak for the instrument thing. I tried to play, well, I should say, my host father, when I lived in former East Germany, he's a musician, and he's like, you've got to learn the guitar, chicks love it. So he restrung a guitar to be left-handed, and I never touched it. And he goes, thanks for never touching that guitar that took me like five hours to restring upside down. I don't know why it would take him so long. I've never restrung a guitar, but apparently

he was like a huge pain and he was like, thanks a lot, man, for not even trying. Yeah, because there's balancing involved. Yeah, he like made it perfect tuned the whole thing, restrung the whole thing, and, you know, gave it basically a full tune up and I was like, nah. Yeah, not interested. Could have told me that before I spent the afternoon doing that. Yeah, that's hilarious. But another strong indicator is a fetus's preference for sucking its left or right thumb, like I said. So the preference is maintained throughout pregnancy, but handedness is thought to be decided before our thumbs even develop. How can we know that? It's using the ultrasound studies. Researchers can observe a fetus's

earliest arm movements, as early as 10 weeks to determine a preference. So a fetus will often make faster, more precise movements with its dominant arm. And by 18 weeks, the hand's structure is developed and one side will reach toward their face, mouth, and eyes more. Crazy. So we can spot a lefty before they're born by seeing which side they favor. I mean, I guess that makes sense. Yeah. I mean, it's still kind of a chicken and egg problem, though, because we don't know if the fetus is positioned that way because it's predisposed to be left-handed, or does the position create preference? So the new reveal party trend should be like, congratulations, it's a lefty. Oh, God, yeah. Pink, blue, or Southpillar.

As long as you cause a massive forest fire, it's fine. Please do not invite me to a handedness reveal party. Yes. We'll not go. Plus, it wouldn't be 100% accurate because other factors do nudge handedness, like hormone exposure, womb space, even your birth order. They all play subtle roles. I didn't know that. Is that because all that stuff has to do with the hormone balance, birth order and all that stuff?

because I remember I did a show a long time ago, and I'm going to get this potentially wrong, but I think that the guy had said, second-born or third-born men are more likely to be gay. And apparently there's like a big trend, a correlation, I should say, with that. And I thought that was kind of amazing. And he's like, yeah, it's not a coincidence. The hormones in the womb change after a child is born. So it's like the first child is born and all the hormones change, but not right in the beginning. And then when the second child is in there baking, it's like the hormone environment is

already totally different than it was for the first child and that changes stuff. Absolutely. And like we said when a woman ages too, so it depends. Her hormones change. So yeah, there's a lot of little factors that determine our chemistry. So we live an interesting womb life. But once I'm born, I pop out into the real world and then what? Can my handedness change after that? Yeah, it's believed to some extent they can. So after birth, genetics team up with environment. Cultural factors start to matter. And kids imitate what they see, their parents, teachers, and siblings, what they're all doing. So like if my dad's a righty and keeps handing me spoons from that side, boom, I can turn into a righty for life or what? Yeah, I mean, it's possible.

But the spinal cord itself shows left, right differences early on. And that indicates what babies see and imitate. That's how it all gets reinforced. So for centuries, society has been biased towards right-handedness. And that can matter for some people. Some schools force kids to switch to writing with their right hand, even if they favor the left naturally. Yeah, I've actually heard these stories, nuns smacking people with rulers yelling, you know, use the right hand. You're going to anger God or something.

I mean, that was literally my experience. Wow. Second grade, Sister Collins. I look back and really think she feared me and thought I was some kind of devil's intern. I had red hair. I was left-handed. She made me stay after school to practice writing with my right hand. And the results looked like crooked, out-of-control penmanship, like a ransom note or something.

It wasn't long after that. I was politely asked to switch to a public school because I was so devilish, I guess. And now, here are some sponsors that won't smear all over your hand. We'll be right back. Have you ever had a moment where you think, man, someone should really do something about this. Then you realize, maybe that someone is you. Well, with the help of GoFundMe, you can change someone's life. You could start a GoFundMe to help a friend pay for school, fund that new community space, or help a local kid finally get to that national competition. I've seen this myself.

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It's a two-minute read or less, something very practical that you can apply right out of the box. People love these emails. You love reading them, I love writing them. You can sign up for free at Jordan Harbinger.com slash news. Now, back to Skeptical Sunday. Here's what I never understood about religious schools. By the way, born rotten, no surprise. You would think they get a bad kid or even a not bad kid that has red hair and they're like,

challenge accepted, right? Like, isn't the whole idea, hey, we're going to make you into a good person? They seem to be like, eh, this is a little bit too much work. Go to public school with the rest of the schmows. I know. They just lots of hatred in the... Yeah, what's that? There's no hatred like Catholic love.

I think I read that on Reddit. Sorry, don't hate me. Don't at me. I'm probably getting that wrong. Anyway, continue. But yeah, but left-handed individuals were often viewed with suspicion. They were accused of witchcraft and even punished in some cases. There's a myth that left-handed writing was banned by Pope Innocent the Aceh.

in the 1600s, but I couldn't find any proof of that. What is documented is that writing with the left hand was considered a direct affront to divine order, further cementing the notion that the right hand was God's hand and the proper way to perform holy and virtuous acts. By the way, I want to be clear. I'm not throwing shade on Catholics. I don't know anything about it. Just something I heard because Catholics, I guess, are really strict in the upbringing, in the schools. Not trying to get hate mail for any of this. It's not something that I necessarily believe. It's just something I keep hearing. So the control of the Catholic Church, by the way, speaking of hate mail, the control of the Catholic church, it really does cross a lot of boundaries. No one ever tried to force me to write with my right hand.

But when I lived in the former East Germany, I remember my friend Nancy, she saw me writing with my left hand and she was like, whoa, you're left handed. I've never seen that before. And I was like, what are you talking about? That doesn't make any sense. How is that even possible? And she's like, oh, well, we weren't allowed to be left-handed. I'm like, what do you talk? Allowed to be left-handed, you just are or you aren't. You can't not be allowed to be. That doesn't make any sense. Of course, I had no idea. She goes, no, if you tried to write with your left-hand, they wouldn't let you do it. I'm like, what happens if you just do it? She's like, yeah, you weren't allowed to do it. They didn't let you do it. And I was like, so how does that

make any sense? She's like, I'm pretty sure that I was born left-handed and it took a long time for me to become right-handed. And I was like, you should go back. You live in a free country now. There's no more, you know, Stasi that's going to report on you for writing with your left hand. She's like, oh, I couldn't do it now. It's too late. You know, she was probably 16, 17 years old at that point. And it's kind of a bummer because I'm like, man, they beat your nature out of you by making you stay after school and write, you know, using your right hand. That's really strange that everybody wanted things in a uniform fashion, you know.

I mean, it traces back to all these older taboos. Cultural conditioning is huge and that can influence our hand dominance. In some societies and cultures, using your left hand for daily tasks, especially eating, is still considered rude or unclean. Yes. Oh, my gosh. Oh, by the way, in the former East Germany, that whole right-hand, left-hand thing, that had nothing to do with religion. Religion was, I won't say outlawed, but very, very, very discouraged. And so it had nothing to do with being Christian or Catholic or religious in any way. It had nothing to do with that. It was just conformity. They love conformity in communism. You know, they're not. don't want somebody who does things differently because, well, yeah, they don't want anybody to be different. Something, something, everybody's equal. Sure. So the, not using your left hand to eat, that has to do with using the left hand traditionally in some society's cultures, whatever, for toilet business historically. Is that correct? That's right. There was a time before toilet

paper and hand sanitizer, and the left hand was the bathroom hand. Yeah. So hygiene, wiping, all that glamorous stuff was the left hand's duties. That is a tough break for us lefties, and I hate that I'm doing this. But again, when I lived in the former East Germany, there was a gal named Olga, and she had done her exchange year in Indonesia. And I was like, Indonesia, what's that like? And she's like, I loved it. The only thing I didn't like was that everybody uses their hand in the bathroom.

And I'm like, what are you talking about? This is my introduction to this. And I was like, so you wiped your butt with your hand? She's like, no, I was special. I had toilet paper. And I'm like, but what happens if you just go somewhere and you have to go to the bathroom? There's no, no, no, no. I carried toilet paper with me everywhere for the entire year.

Because otherwise, what if you're out hanging and you're like, oh, I kind of have to go to the bathroom and you go to the bathroom, even number one, right? If you're a gal, you need to wipe and it's just like there's no paper in there. And why wouldn't that catch on? Again, I don't want a bunch of hate mail, but it's like there was a time before toilet paper. Yeah, but it's been around for like 100 years. Maybe we want to reform our cult. Nah, we'll just keep wiping our butts with our hands. Sorry, I don't mean to be all ethnocentric or whatever, but bruh.

Even ancient Rome had like the sponge on a stick. Exactly. Yes. Have you not seen the seashells or whatever it was? What is that movie with Sly Stollone and Sandra Bullock? Oh, God, I forget what it's called. I know what you're talking about. Is that demolition man?

Demolition man, that's it. Yeah. And they're like, ugh. He's like, I have to go to the bathroom and she hands him like some seashells. Or was that when they were going to bang? I can't. Anyways, please rescue me. Tell me more about wiping your butt with the left hand and get me off.

this topic. I will say it is why everyone shakes hands with their right hand. That and shaking with the right hand is, you know, it's an old school peace signal. Yeah, it's probably pretty aggressive to offer your poop hand as a greeting. Like, hello, yes. And the right hand was the weapon hand. So offering it meant, look, you know, no dagger. And the up and down shake part is basically a medieval TSA check to make sure nothing pops out of your sleeve. weapons on the right, hygiene on the left. Oh, God, yeah, definitely. I mean, in parts of India and the Middle East,

it's still considered rude to eat or handle food with your left hand because it's associated with hygienic duties. So if you're traveling and you're a lefty, maybe don't reach for the non without thinking. Right. If you travel internationally, you'll definitely want to be mindful of what hands you're using, for sure. So we're not just born this way, we're trained this way.

It seems to be, at least for some people. I mean, my experience has left me ambidextrous. Admittedly, I don't write with pen and paper as much anymore. But before phones and laptops, I'd switch hands while writing without even noticing. But beneath all of this, the brain's wiring drives a lot of it. Left-handed people are shown to have a larger corpus callosum. Why does that sound like a penis part? Is that a left hand?

Is that a left hand in your pocket? But what is that? What is that thing? The bridge that connects the two hemispheres of our brain. So lefties often have a larger one, which means faster communication between both sides. I always knew lefties were hung in the brain. So our brains are basically the high-speed Wi-Fi of the brain world. Nice.

Sure, sure, yeah. I mean, that inner hemispheric connection helps with multitasking and creative problem-solving. So lefties are better multitaskers? Is that the case? Lefties seem to have an advantage in multitasking because you process information more quickly. This gives lefties an advantage in activities like video games or sports. And according to research, lefties can oftentimes be better multitaskers because they have that larger corpus callosum or part of the brain that facilitates communication between the two hemispheres. So multitasking is just the ability to use both sides of the brain simultaneously.

That's one way to put it. Sure. It's more of a fast, like, ping pong thing going on. That's also why more left-handed people are found in creative fields. So creative lefty, that thing is not, that's not just a stereotype. There's some truth to it. Lefties tend to rely a bit more on the right hemisphere, which is the one link to creativity, imagination, and spatial skills. Again, not a guarantee, but it's more likely. There are some uncreative lefties out there, too, but there are lots of claims. that left-handedness means creativity, a high IQ, and artistic talent. I always figured my lefty brain gave me a unique edge somehow, but usually the everyday annoyances wash that out. Many left-handers do have more creative talents since lefties more often utilize the right side of the brain, which, you know, it's just touted as the more artistic side. And that's according to the National Library of Medicine. Okay, so our bigger brain bridge lets us communicate between both sides of our brain at once.

It's a team effort, man, DNA, hormones, superstitions. I can only speak from my experience, but lefties are, I've heard, more intelligent too, right? People always say that, but it kind of sounds like one of those pat yourself on the back, urban legends and not really science. And you're better at the humble brag, apparently. Oh, yes. Masters of humility. Left-handedness has been linked to higher IQ scores in several studies, with more left-handers scoring over 140 than right-handers. Yeah, thank you. Again, I've been waiting for this validation.

Yeah, well, you're welcome. But settle down. Lefties aren't automatically geniuses. Okay, fine. But again, I have been told that there's a difference in how lefties process languages and stuff, for example. Are we wired differently for that as well? Some studies suggest, yes, left-handers process language using both hemispheres of the brain, while right-handers mostly stick to just the left hemisphere.

I see. Okay, so, yeah, losers. Got it. Well, it just means lefties. have more inner hemispheric communication, meaning more cross-talk between the two sides of the brain. But it does come with a higher rate of dyslexia, especially among mixed handers, you know, the people who switch hands a lot. Anecdotally, I've never experienced dyslexia, but a lot of lefties do. Interesting. But that's only because you, the nuns made you learn how to do

that. So you switch hands, but maybe you wouldn't have if you weren't getting beat with a ruler. Right. I don't think so. And I mean, I can write. I can. bat, I can play pool with both hands. Okay, maybe then. Yeah, but eating with my right hand is really uncomfortable. I can't bowl or throw a dart or throw a ball with my right hand, though. Yeah, I don't know. I'd have to try those. I'm at the point where I'd have to try many of those things to even know, because I can do weird stuff with both hands that people don't expect. And then it's like, here's a fork. And I'm like, I can't, how does it work? Right. So I really have to try everything. I doubt I could play pool with both hands.

There's no way I could bat with both hands. I probably do golf or something left. I right left. Throw left. But I don't know if I could bowl or throw a dart or a ball right-handed either. So I don't know if I'm ambidextrous then because it's just such a crapshoot at what I'm going to be able to do with either hand. And it's weird, right? I mean, you don't even think about it.

It's just this is what I pick something up with. Right. And even how you draw can reflect which hand your brain prefers. Like left-handers often sketch people facing the right side of the page, probably because of how the hand moves across the paper. And it's the opposite for righties. And this is true for drawings by adults and children. Art imitating ergonomics.

I would never notice that, but now I'm going to have to go back and look at my sketchbook, which doesn't exist because I can't draw at all. But I also, you know, I also shoot weapons right-handed. But that's also kind of like more to do with my eyes maybe than my hands. Right. Because if I put the firearm in my left hand and I close one eye, stuff moves. So that doesn't really work. Anyway, I got missed with the drawing gene.

So, again, you use both hands because your weird Catholic school nuns who were abusive beat you into it. But can people actually adapt to a different hand? It seems like you probably could if you had to. Yeah, I mean, to a degree. I mean, the brain is plastic. So you can train it. But most people still have a dominant side. Cultures, you know, like we were talking about East Germany, they try.

to control what hand you write and eat with, but it can't control every movement you make in the world. Evolutionary theories suggest left-handedness might have offered an advantage in combat because opponents weren't prepared to defend themselves from that angle. So it's not a sucker punch, it's just an evolutionary advantage. Like in baseball, I've heard lefty pitchers have a huge advantage somehow, and it has to do with the term Southpaw, right? I mean, everyone thinks that. I thought that.

The idea that it's because the left-handed pitcher's arm is on the south side of the diamond. But the term South Paul showed up in 1813 in a publication called tickler. Okay. Decades before baseball existed. I mean, anything called tickler now is pornographic. They were more innocent about it back then. Yeah, 200 years ago, I guess, we'll let it slide. So, okay, so this is not a baseball term.

I guess I always assumed it was a baseball term. Yeah, me too, but it actually originated from boxing. So historically north and right were associated with heaven and angels. South and left, that's the devil's territory. So Paul meant hand. And South was linked to sinister, which is Latin for left. So a sinister punch was described with the slang South Paul. It's just another linguistic reminder that lefties were literally seen as evil.

I mean, devil paw would be cooler, I think. It'd be so much cooler. Yeah. But the word was seen in a few political cartoons as well in the 1800s, describing like debate beatdowns. But then baseball came along in the 1840s. So boxing created it, baseball popularized it, and now nobody knows where it came from. Right. Yeah.

I mean, baseball changed the meaning a bit. So fields were best designed with home plate facing east so batters wouldn't stare into the sun. That meant a left-handed pitcher's throwing arm ended up on the south. side of his body. So baseball just borrowed the term and changed its origin story. That makes sense, because I feel like I've chat GPTed this or Gemini or whatever this ages ago and it told me it was a baseball term or somebody told me it was and that was the end of that. So all right, baseball became so big everyone just associated Southpaw with a left-handed pitcher. That makes sense. Yeah, right. And in fact, left-handed athletes dominate sports where you face an opponent. So sports like boxing,

baseball, tennis, and fencing. You know, lefties win more fights and boxing matches. And research has shown that left-handed boxers win more because they confuse opponents with their stance. So left-handed athletes don't have a disadvantage. It's actually an advantage. Yeah, a lot of times it's the advantage, yeah. I guess it does seem like more and more major league baseball players bat left-handed these days, or is that just my imagination? Yeah, I mean, I think a lot more tend to bat left and right, and that has to do with them trying to get the advantage on the pitcher, whether the pitcher's right or left-handed, especially a pitcher, because they can generally throw curveballs and sliders and other trickier pitches that make it harder for those at bat

to hit successfully. All right, y'all, you don't need genius mermaid astronaut genes to make smart decisions, like checking out the fine products and services who support this show. We'll be right back. Thank you all for listening and supporting the show. It is your support of our advertisers that keeps the lights on around here. All of the deals discount codes and ways to support the podcast are searchable and clickable on the website at Jordan Harbinger.com slash deals.

Now for the rest of Skeptical Sunday. You know, I realized when I trained with a boxing coach, I could switch my stances, and I kept doing it thinking, oh, darn, I keep switching. And he's like, no, no, no, you got to keep doing that. Because if you can box with both stances, that's going to be incredible. Because most people can't do that. And he's like, dude, if you do that, like the middle of the, fight. He's like, your tired opponent is going to get wrecked. Of course, the problem was I was

terrible and never made it past the first couple of rounds because it's like, you know, this is really hard and tiring, and the guy who can jump rope for half an hour has a little bit of an edge on me. And also getting punched in the face kind of sucks. This isn't for me. I suppose it makes it harder for a right-handed pitcher to throw to a lefty batter. Yeah? Yeah, I mean, and left-handers are overrepresented in sports. Like, left-handed water polo players are rare, but they offer a competitive advantage because they're able to face both the goal and be responsive to teammates if you, and Water Polo is not that popular, but it is an interesting formation how they can take

advantage over their right-handed opponents. It's similar to tennis. A left-handed tennis player has an advantage over their right-handed counterparts because playing tennis as a lefty, it forces the opponent to respond to different angles and spins and serving positions. That makes sense. I guess I should be out there. hustling all the righties. Yeah, you might be able to. I mean, left-handed pool players have an advantage because they have better angles for certain shots. They can often shoot righty as well from the simple fact of just adapting to a right-handed world. And fencing gets interesting when a lefty is an opponent. It just confuses everything a right-handed person trained for. There's even a classic

scene about it in that movie The Princess Bride. Right, because they're throwing from an angle nobody expects. It's like the Jedi mind trick of athletics. Yeah, for sure. And this isn't athletics, but another interesting fact is that astronauts are more likely to be left-handed. So you're telling me lefties are not only better athletes. We're also literally leaving the planet. Right. About 60% of astronauts are left-handed, which is a rate much higher than the general population. That's wild. Do we have any reason why that is? I mean, there's nothing solid, but it does point back to how those cilia are formed in the womb. Since they influence our hearing and vision, that seems to be a factor for things like astronauts, pilots, even underwater divers. Why would it affect divers? This is weird and not sure what it means evolutionarily, but studies overwhelmingly show that left-handed people adjust more easily to seeing underwater and have far better vision below the surface than righties.

Okay, lefties are better. Athletes, astronauts, and mermaids, this is getting unfair. I guess I feel better about all those scissor and pencil on my hand incidents throughout the years now. Yeah, I mean, it's in everything. It's not just with our hands. We have dominant feet. You know, consider skateboarders and surfers who ride with what's called goofy-footed. Even animals show handedness. Cats, dogs, horses, chimps. No, male cats are more likely to be left pawed. Left pod. So the animal kingdom's got lefties and righties. I had no idea. Yeah. Many animals are handed or pawed. So handedness in animals is a widespread phenomenon, not an exception and can provide insights into evolution and brain development. So studies on cats and dogs show a significant portion of each species has a dominant paw, though the ratio of left-to-right pod individuals can vary. But male cats are more likely to be left-pod when completing tasks. like getting food from the bowl or things like that.

Other mammals like horses, squirrels, and chimpanzees also show limb preferences for tasks like cantering, stripping acorns, or using tools. I never considered what hand or paw my pets were. So even my cat is in on this. I knew it. It's been knocking over cups with his left paw this whole time for science. Why is that, I wonder? I mean, it's all tied to brain lateralization where different functions are concentrated and

one of the two hemispheres of the brain, so we see it in every species. For example, like young chicks tend to peck grain on one side. Tortoises consistently turn to one side to right themselves when flipped over. In the animal kingdom, there's an evolutionary advantage to favoring the left, even if you don't have hands. Like snails, with left coiling shells, have an advantage against predators who have adapted to crack more common right coiling shells. Isn't that crazy? Remarkable. Yeah, that is crazy. Wow. Don't tell me fish are left and right fined or whatever. Actually, they seem to be. The blue whales perform specific movements like barrel rolls to feed with a preferred side, showing a consistent handedness or fined, whatever you want to call it in their behavior. Yeah. The octopus, which by the way is

my least favorite animal on the planet, has eight equally nimble arms, but they show a preference for using one tentacle to inspect or handle objects. So they favor a tentacle. It's kind of their dominant arm. That is cool. So the animal kingdom is basically full of lefties, righties, the terrifying octopus. Love a good octopus. But what's your beef there? I don't understand. I mean, this is off topic. It's just my lifelong phobia. I can't even watch the Little Mermaid, Jordan. It's not just me. It's called chappetophobia, and it sucks because I surf all the time. I've come face to face with a giant one once, which still gives me nightmares.

What? I am not suggesting this is rational, but, I mean, even a photo will make me panic. And literally talking about it right now, my hands are clammy. Wow, that's crazy. So I take it you have not watched my octopus teacher on Netflix. No, no. Face your fears. That is crazy.

I never heard of this. Yeah, it's not. something I'm proud of, but let's move on. All right, fine. But reptiles and birds also show favoritism to one side and any species from kangaroos to lizards. You know, we learn a lot about handedness from animals. And handiness is often task specific. So it can be influenced by whatever task is at hand. For instance, you know, some great apes don't show hand preference for social tasks, but exhibit it for tool use. I have a friend who can only snap with her left hand. Like, why? Why is that? Nobody knows. Some people don't always golf or bowl or shoot a gun, like we said,

to match the hand they write with. It goes back to what you said about the eyes, because it's not just handedness. We have dominant eyes, feet, sides we chew on, which nostril we're breathing out of. And they don't always favor the same side, right? It's not random chaos. It's not random chaos. It's It's evolution's way of saying, hey, let's specialize here. So being a lefty isn't weird. It's just nature having a good time. Just thinking about all these physical expressions. Is it doing anything we can't see?

Like, you know, are there health issues that affect lefties? You know, like, when we did the redheads thing, it was like, oh, skin cancer and temperature and all this stuff. It's like, oh, my gosh, your hair color can affect all that. Is there anything also linked to TBBB4B that's like, oh, and also you're going to, you know, your liver's bigger or something. I don't know. Yeah.

I mean, we think so. I mean, there's definitely some things in, like, lefty fine print. It's very early on in the research. But left-handed people tend to hit puberty later than their peers. There was a study that showed left-handed boys reached puberty about a year later than their right-handed peers. More studies are needed on this, though. I was a bit of a late bloomer. Now I have a medical excuse, I suppose. That's because you're left-handed. There's another weird biological fact. And this isn't just a left-handed phenomenon. It's true for both right and left-handed people. Whichever is your

dominant hand, your nails grow faster on that hand. Really? How weird is that? I've never noticed that, but now I'm definitely going to be comparing my pinky nails. Yeah, I know. I've been checking it out since I read that. And there's less fun facts, too. I mean, according to a few studies, left-handers have a higher chance of developing immune disorders and conditions such as allergies. This isn't to say every left-handed person suffers from bad allergies, but if you're a lefty and tend to get a runny nose or itchy eyes, then this may be connected to those modified microtubules. It's currently being researched. A small price to pay for all the advantages that we seem to have, I guess. I don't know. Not a big deal. I'll take a runny nose. No problem. I'm going to

space. Another inexplicable health effect is that left-handed people are more likely to drink more often. So the research on this is really limited, but there have been some studies showing a significant correlation between left-handers and an increase in alcohol consumption. This isn't to say that left-handers will become full-blown alcoholics, but on average, they do tend to drink more. I mean, in my 20s, that was definitely true slash early 30s. Yikes. So evolution made us better athletes and more fun at parties. Great. Maybe.

A lot of this is correlation, though, not causation. But another thing seen in higher rates in lefties is that they report more vivid dreams. Of course we do. We're so busy dreaming about being left-handed astronauts with 140 IQs in perfect underwater vision. I don't know, but it seems from what I've read, it's probably because their brains won't stop multitasking in both hemispheres. But studies indicate left-handed individuals are better able to recall having vivid dreams at night. And on the flip side, left-handed people are more prone to insomnia. So if you have difficulty sleeping and are left-handed, then that could be a reason why. Huh. Okay. So all of these little traits seem to be connected to this specific genetic coding. And at the end of the day, does any of it really matter?

It definitely does. You know, handedness is a window into how the brain organizes itself before we even take our first breath. It's a mix of genetics, environment, and these little dashes of randomness. So some people are born ready to strum a guitar upside down, and the rest of us are just trying not to smudge the ink. I guess it depends on a few other factors. Yeah, so many things. And that's just one way to sum up 50 years of neuroscience, I guess. It is interesting to observe the high rates of lefties in the arts, though. You know, Oprah, Lady Gaga, Hugh Jackman, Bill Gates, Julia's Child, Gordon Ramsey, Da Vinci.

It's a really long list, and the rates are higher. than in the general public. So again, it's not the Jews running Hollywood. It's the lefties. Or is it all of us left-handed Jews? So lefties run daytime TV, pop music, tech, and dinner. Great. What's next?

The White House. Actually, I'm curious about that. Are there any lefty presidents? Yeah, it already happened. 20% of U.S. presidents have been left-handed, including Obama and Clinton. A high percentage of politicians through the ages have been lefties, much higher than the general population. Julius Caesar and Napoleon were left-handed.

Bill Clinton being a lefty explains why the writing on my Eagle Scout Award was, so you get a letter from the president, and the writing on there is, it's pretty messy. There's probably another Bill Clinton joke in there I could have chosen, but let's move on. Let's let that one just slide up by. So Conquerors, presidents, and us. Okay, lefties, we get it. We're cool on a historical level. Amazing. Yeah, I mean, that tracks, Tina Faye, Cardi B, Chuck Norris, all lefties.

Of course, the roundhouse kick comes from the left side. They never see it coming. Yeah, and we can celebrate this rare trait every August 13th, which is left-handed day. That's a thing. Okay. Yeah. Whoever sets these kind of things suggests everyone try using their left hand as much as possible that day. I'm on it. And it's fun to see how long you can try and use your less dominant hand for things. Because it's such second nature. It's just you forget. You know, it's just who we are. I like that, you know, just try eating with your less dominant hand for one day, listeners, and report back.

I think eating is one of the hardest things to do with your non-dominate hand, aside from writing. Yeah, I think so too. But it just comes down as a chance of so many different variables. We think that most instances of left-handedness occur simply due to random variation during development of the embryonic brain without specific genetic or environmental influences. but we will understand it more and more as we continue to decode our genes. You know, there's just no doubt handiness is complex. It's not just inherited. It's part genetics, part environment, part chaos. You know, it's a small club.

And what it means evolutionarily, we're still figuring out. So being a lefty just reminds us how wonderfully weird the human brain is. And if you're left-handed and listening, congrats to this episode was made for you, the rest of you, everything else on the planet. it was designed for you, so I don't want any complaining. Thanks, Jess, for getting us on the right side of being left. And thank you all for listening. Topic suggestions for future episodes of Skeptical Sunday to me, Jordan at Jordan Harbinger.com, advertisers, deals, discount codes, and ways to support the show, all on the website at Jordan Harbinger.com slash deals. I'm at Jordan Harbinger on Twitter and Instagram. You can also connect with me on LinkedIn. Jessica can be found on her

substacks between the lines and where shadows linger, and we'll link to those in the show notes as well. This show is created in association with Podcast One. My team is Jen Harbinger, Jace, Sanderson, Tadasidlowskis, Robert Fogh, Ian Baird, and Gabriel Mizrahi. Our advice and opinions are our own, and yes, I might be a lawyer, but I'm certainly not your lawyer. Also, we try to get these as right as we can. Not everything is gospel, even if it's fact-checked. So consult a professional before applying anything you hear on the show, especially if it's

about your health and well-being. Remember, we rise by lifting others. Share the show with those you love. If you found the episode useful, please share it with somebody else who could use a good dose of the skepticism and knowledge we doled out today. In the meantime, I hope you apply what you hear on the show so you can live what you learn, and we'll see you next time. What if we're not just close to building matrix level simulations, we may already be inside one. You're about to hear a preview of our episode with Rezwan Verk on clues we're living in a rendered world.

The simulation hypothesis is basically the idea that what we think of is the physical world, you know, like this table, this chair, that all the physical reality is actually part of a virtual world. The simulation hypothesis, the subtitle is an MIT computer scientist shows why AI, quantum physics, and Eastern Mystics agree we're in a video game. There have been a number of physicists who aren't looking at the world as information now. So there's a whole branch of physics called digital physics. Instead of looking at things like conservation of energy and conservation of momentum, you're looking at conservation of information. Does information get created or get destroyed? And some have even said that the world itself is basically a quantum computer,

if you think about it. And so that would be, whatever computational substrate is being used around the simulation would have to be a lot more advanced than what we think of as computers today. I use the metaphor of video games that the world is the type of massively multiplayer online video game

because that's sort of my background was in building video games in Silicon Valley. Now, there's a lot of different flavors of simulation theory when you kind of delve deep into it. And probably the most popular expression of that in the media has been the film The Matrix. Because, you know, Neo thought he was in a real physical world, but it turns out he was actually in a virtual world.

But now AI is moving so fast that I think we'll get to that point much more quickly, and certainly within the next 50 years, 100 years at the max. For the full conversation that will make you question every assumption you've ever held, check out episode 1239 of the Jordan Harbinger Show with Rizwan Verk. This episode is sponsored in part by Something You Should Know podcast. Find a new great podcast shouldn't be this hard, so let me save you some time. If you like the Jordan Harbinger show, you'll probably like something you should know with Mike Carruthers. It's one of those shows that makes you smarter in a practical, useful way.

Same curiosity vibe we go for here, just in a fast-focused format. Mike brings on top experts and asks the exact questions that you'd want to ask, and the topics are all over the place in the best way. Recently, they've covered things like why we care so much what other people think, the benefits of laughter, why sports fans get so invested, and what makes people like you or not, the through line is always the same. Smart ideas you can actually use in real life. Something you should know has been featured in Apple's shows we love, and it's got thousands of five-star reviews

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