Stuff You Should Know - Why Do Lefties Exist?

Episode Date: February 24, 2015

For at least the last 200,000 years, between 10-15% of the human population are left-handed and this fact has utterly left science baffled. In searching to explain handedness, all sorts of contradictory evidence has emerged, creating a fascinating mystery. Learn more about your ad-choices at https://www.iheartpodcastnetwork.comSee omnystudio.com/listener for privacy information.

attention bachelor nation. He's back. The host of some of America's most dramatic TV moments returns with the most dramatic podcast ever with Chris Harrison. During two decades in reality TV, Chris saw it all and now he's telling all. It's going to be difficult at times. It'll be funny. We'll push the envelope. We have a lot to talk about. Listen to the most dramatic podcast ever with Chris Harrison on the iHeart Radio app, Apple podcasts or wherever you get your podcasts. On the podcast, Hey Dude the 90s called David Lasher and Christine Taylor, stars of the cult classic show Hey Dude, bring you back to the days of slip dresses and choker necklaces. We're going to use Hey Dude as our jumping off point, but we are going to unpack

and dive back into the decade of the 90s. We lived it and now we're calling on all of our friends to come back and relive it. Listen to Hey Dude the 90s called on the iHeart radio app, Apple podcasts or wherever you get your podcasts. Welcome to Stuff You Should Know from HowStuffWorks.com. Hey and welcome to the podcast. I'm Josh Clark with Charles W. Chuck Bryant and Jerry's over there too and this is Stuff You Should Know, the podcast. Man, oh man, I would love for people to just be a lie on the wall in the studio sometimes. We get squashed. There's a lot of fun pre-record today people. I hate that you miss out on that kind of stuff, but you know what? That's for us. We deserve a little something. Yeah. That's called pre-show fun. Fun. Hammering out the details.

Hammering out the details. I thoroughly enjoyed researching this one. Oh really? It burned my brain a little bit. It burned my brain a little bit too, but I just didn't know anything about handedness. You didn't? No, not really. Don't use your hands much? Well, I mean, as far as why you are left or right-handed or ambidextrous, it was all kind of new information for me. Yeah. I feel like I had read that io9 article, which we should give a huge shout out because it was forming partially the basis of this episode. Yeah. Why are so few people left-handed from io9 and they sourced a lot of great stuff from Discover Magazine and their article. And science. And science. So it's legit. It is legit. Possibly even too legit to quit.

Which I could not do with my left hand. I guess I can. I just did it. You just did two. You're signing to me. Yeah. I'm equally bad at doing too legit to quit finger motions with either hand. I'm right-handed, by the way. What about you? I'm right-handed, but that is weird since you have your MC Hammer pants on. I thought you'd be good at that. That's all just... It's not hard to put on pants. It's hard to do two legit to quit finger motions. Yeah. I'm right-handed to, well, I was about to say to a fault, but heavily, heavily right-handed because after reading this, I do believe that there is a bit of a spectrum, I think. Oh, yeah? Yeah. I think some people are way dominant with their one hand and some people skew more toward, yeah, I can do some things with

this hand. And some people are ambidextrous, which we'll talk about. Very few, though. Fewer than you think. Yeah. But I am heavily, heavily right-handed. I cannot do many... What's the word I'm looking for? My fine motor skill tasks, I cannot do very well with my left hand. I can just club things and smack things and... Knock stuff over. Yeah, knock stuff over. You're like Frankenstein clearing a table. Pretty much. What about you? Can you do anything with your left hand? I used to think I was pretty much just strictly right-handed, but then, especially researching this, I paid attention. I'm like, no, I used my left hand a little more than I thought. I'm definitely not ambidextrous. And if there is such a thing as a dominant hand, it's clearly my right.

But this article points out, or actually it was a science article that said there's this idea that there isn't a dominant hand, that you have uses for both hands and one kind of specializes in one thing and one specializes in another. And the example they used to illustrate that was cutting like meat with a fork and knife. Yeah, I was going to ask you about that. I was thinking about it. I was like, oh yeah, I guess I do use the knife pretty well with my left hand. I thought, crazy, no, my fork is in my left hand. Yeah, me too. My knife is in my right hand. Me too. And then, I switched the fork over to my right hand. That's what I do too. I was going to ask you that. So, I'm definitely right-handed, but my left hand does a great job holding the steak in place with my

fork while I cut it with the knife. Yeah, well, I come to think of it though. I play guitar in drums. So, I mean, I have some left hand skill, I guess. And I know if you break your dominant hand, you're going to learn pretty quickly how to adapt. So, it's possible to learn. Yeah, it forced to. Yes. It's all very interesting to me. It is. And we should say if you happen, happen just randomly to be listening to this episode on August 13th, happy national left-handed day. Yeah. When I looked that up, I was like, how wouldn't it be one of those other stuff you should know coincidence if this was happened to be released that week or something? No. Not even close. No such luck. Yeah. And it's good that left-handed people have their

own day because they've been fairly maligned throughout the millennia. Yeah. Let's talk about that actually. Okay. Throughout history, in fact, even if you look at the words throughout history, there is a, you know, they poo poo left handers basically. Yeah. Like the word Lyft. Lift. Yeah. From Anglo-Saxon means weak. That's where the word left comes from. Yeah. And the word sinister from Latin is the word for left. Yeah. Anybody who saw that episode of The Simpsons where Ned Flanders opens the leftorium knows that. That's right. I have a sinister reason to invite you all here. Sinister meaning left-handed. Man. And that was when he announced the leftorium. That show was so smart, you know. Very smart. So many of those jokes like just flew over my head

back in the day. Well, now they're coming back to roost. There's a long list of countries who have languages that link the word right with being good. Yeah. And the left with being bad or wrong. And in some countries, even making hand gestures with your left hand is a no-no. Well, in a lot of countries or a lot of cultures that eat food with their hands rather than utensils, using the left hand to eat or do a lot of things with is considered taboo because it's exactly right. You use the right hand to eat with, use your left hand to wipe with, right? And I think if you pay attention and notice, I'll bet you have a hand that's dominant in that activity. Wiping your butt? Yeah. Yeah, I'm already. Are you? Oh, yeah. Okay. But if you try the other hand, it will feel very

weird. Whatever hand you use normally, it's going to feel weird if you use the opposite. Yeah. And you'll just end up very messy. I wonder if you had a subconscious thing like, you know, I was just eating these candy pecans with my right hand and I know I'm going to go back and eat them with my right hand. Oh, I don't even use my hands to eat. I'm a little too germ conscious. I scoop food up in the crook of my elbow, which is very clean because it doesn't come in contact with other stuff. And then I eat out of the crook of my elbow. That's pretty funny. So why have people been, I mean, why have they picked on left-handed people? There are some theories that it's just a minority, you know, 10 to 15 percent of people are left-handed and throughout history, minorities

have been picked on. That's right. That's one thing. Yeah. There's at least a couple of cultures that equate left-handedness with clumsiness. Yeah, that makes sense to me. Some hypotheses theorize that tools, tool making for a very long time has been done following right-handed techniques. Still is in many cases. Sure. Yeah. And so when a lefty was trying to make tools or do whatever using right-handed tools, they would have been clumsy with them. And therefore, the idea that left-handed people were clumsy or weak or whatever could have developed and carried on. Yeah, like colonial day dad is teaching his two sons, well, let's go with the son and a daughter even. Let's mix it up. How to use a saw. And you know, the son's left-handed and he keeps,

he can't saw well. So the dad's just like, he favors the daughter because she's, you know, she's better with the saw. Right. It's just, it's easy to see how that could happen. Like he's mad at Roger but pleased with Prudence. Yeah, because Prudence, she's always sawing things well. That's a colonial name, right? Yeah, sure. Well, I feel like it is. Okay, well, what else is there? Who? Goodie Alice. Okay. It's timeless. But there's still that, if you're a lefty today, you might be frustrated with things like scissors and can openers and spiral notebooks and things that sort of favor the right-handed. Yeah, sitting next to a right-handed person at dinner, the elbow thing. It's the worst. It's because there's so few left-handed people.

If you're planning a dinner party, first of all, it's just common courtesy to know the handedness of all of your guests. Sure. And then to see them appropriately. Right. To put the left-handed person at the end of the table so that their left hand is, their left elbow is off the table and they don't have to worry about bumping into other people. Yeah, my mom is left-handed. My father is right-handed. And you came out right-handed? Yeah. Crazy. I sure did. So despite everybody knowing that there's a right-handedness and a left-handedness, it turns out after investigating this kind of thing, science is really baffled as to what exactly is going on. Why we would have handedness. Yeah, at all. Where it comes from. Why the proportions seem to be steady. There's a lot

of questions that come up when you look into handedness. Whereas the average person would just kind of take it for granted. But no, not the average scientist. No, no. There are a lot of interesting theories, though. One is that, as we all know, we have a left hemisphere and a right hemisphere of our brain. And we are one of the only mammals that are very much, it's called brain lateralization, when primarily, and this isn't across the board, but primarily one hemisphere controls certain things and the other controls other things. And that is primarily controlling the opposite side of the body as the hemisphere. But language and controlling your fine motor skills like things you do with your hands and your fingers have often been linked because they are

generally linked together on one hemisphere of the brain. Right. For the most part, people who are right-handed, they make up the vast majority of human beings, by the way. 85 to 90%. Yeah, I saw as low as 70, but nothing lower than that. No, 80, then, yeah, you're right. Sorry. Exactly. Yes. Those people have their language center in the left hemisphere and I guess also their motor cortex in the left hemisphere. Right. And the, no, the left. And there's a lot of questions about why this would be. And the brain supposedly is always looking for efficiencies as much as possible. Yeah. So they're saying, okay, well, these are two very human activities, speech, language, and using your fingers to do stuff. Right. Right. So they're also some of the more

complex activities that humans engage in. Right. So it makes sense that you just leave it up to one side of the brain so that these things can not have to cross over the corpus callosum. Yeah, it's just like clustered together. It makes sense. It does make sense, but it's also a pretty thin explanation. If you could also say the other, the exact opposite that it would make more sense that our motor skills and our language skills would be in opposite sides of the brain to give each other a break rather than just waiting it down on the same side. The point is, though, is if you crack open a human brain and you look for the motor cortex and the language region, the language center, you're going to find them most likely, statistically speaking,

on the left hemisphere. Hence more right handedness. Right. Because of what you said that, that brain lateralization where stuff that's carried out in the left hemisphere is going to manifest itself in the right. So if you're shaking somebody's hand using your right hand, the left hemisphere is blowing up. That's right. If you're taking in visual information with just your left eye because you got your right eye closed or it was poked out by a seagull or whatever, then your right hemisphere is going to be active. Right. That's right. Interestingly, though, if the opposite isn't true, if you have your language center in your right hemisphere, it doesn't always mean that you're going to be left handed.

Right. It means you're more likely to. But I like the way this article looked at it. It's an evolutionary rule of thumb. It's not, I think they said between 61 and 73% of lefties have the language centers on the left, 90%, over 90% of right handed people. Right. Which raises a really great question. Is there such a thing as righties and lefties? Or is there such a thing as righties and non-righties? Yeah. Because if a rightie and a leftie are equally exactly the same thing, if handedness is completely binary like that, then if you're a leftie, your language center should be on the right-hand side. And like you said, that's just not the case in most lefties even. Yeah. That's true. And the I09 article also points out that they don't know why necessarily,

but this is just how we evolved. It could have just been the opposite. Right. And then we'd have more lefties. Right. Well, that's the idea. But I think there are a couple of explanations, possibly, of genetic mutations along the way. Two in particular, one about 200,000 years ago, that basically mutated us to the fact that we are going to be more right-handed in the language center is going to be on the left-hand side. Right. And then more recently, there's a theory that there was a second mutation, 20,000 between 20,000 and 100,000 years ago, where that basically balanced things out or it canceled that out, which means the possibility of left-handedness became a thing or else we would have all been right-handed. Right. That makes sense, too.

It does make sense in that the humans possibly evolved to use their hands more. And by using their hands more, our brains were forced to become specialized and basically forced to choose. So then some sort of gene was set up that made the developing human brain most likely to be a right-handed person, right? Yes. And then that second gene came along and canceled that out in some parts of the population. Yeah. I think it's the D gene and the C gene. There are two ALLs, which is the manifestations of a gene at the same location. And the D gene is more frequent in the population, so it promotes the right-handed preference. The C gene is less likely within the gene pool. And so there you have like a 50-50 chance of being left-handed if you have that C gene.

Okay. I got you. Yeah. But you don't have a 50-50 chance of being a left-handed person in general. You have about a 10% chance. Yeah, because the D gene is more prominent, and that means almost certainly you're going to be right-handed. Okay. So the caveat we should add to all of this is that this is all just strictly conjecture. Sure. And we'll get to a little more of this conjecture right after this. I'm Mangesh Atikular, and to be honest, I don't believe in astrology. But from the moment I was born, it's been a part of my life. In India, it's like smoking. You might not smoke, but you're going to get second-hand astrology. And lately, I've been wondering if the universe has been trying

to tell me to stop running and pay attention. Because maybe there is magic in the stars, if you're willing to look for it. So I rounded up some friends and we dove in, and let me tell you, it got weird fast. Tantric curses, Major League Baseball teams, canceled marriages, K-pop. But just when I thought I had a handle on this sweet and curious show about astrology, my whole world came crashing down. Situation doesn't look good. There is risk to father. And my whole view on astrology, it changed. Whether you're a skeptic or a believer, I think your ideas are going to change too. Listen to Skyline Drive and the iHeart Radio app, Apple Podcast, or wherever you get your podcasts.

Hey guys, it's Chikis from Chikis and Chill Podcast. And I want to tell you about a really exciting episode. We're going to be talking to Nancy Rodriguez from Netflix's Love is Blind Season 3. Looking back at your experience, were there any red flags that you think you missed? What I saw as a weakness of his, I wanted to embrace. The way I thought of it was, whatever love I have from you is extra for me. Like, I already love myself enough. Do I need you to validate me as a partner? Yes. Is it required for me to feel good about myself? No. Listen to Chikis and Chill on the iHeart Radio app, Apple Podcast, or wherever you get your podcasts. So Chuck, we were saying that it's possible that genetic mutations far back in human history

account for this. And there is a lot of evidence that humans have been mostly right-handed for about the last 200,000 years. Fossil evidence suggests this. Looking at Neanderthals, skeletons, early human skeletons, you can see evidence on the skeletons of right-handedness. And they think that it's so obvious and obviously prominent because these people were using things like spears. So if they did have a hand preference, then a spear would definitely develop that arm connected to that hand and it would stay in the fossil record through the skeletons, right? Yeah. They also have looked at other fossils as far back as 1.6 million years. There's a skeleton called, I want to say the Kokomo Boy, even though it's not, but I love that song. It's the Nario

Kotome Boy. Do you love Kokomo? Sure. And he is a 1.6 million year old Homo Ergaster. Yeah. And he was clearly right-handed as well. Other fossils have turned up evidence of right-handedness. The teeth, striations on the teeth suggest eating with their right hand. Yeah. So what we can say with a pretty decent amount of confidence is that at least for the last 200,000 years, humanity has been the majority right-handers. And there's been maybe about this constant 10, 15% proportion of left-handed people, which makes the mystery even more crazy to me. Yeah. But it also makes sense that in early tool building and teaching how to use tools, I mean, it holds true today. They've done studies that you teach your son or daughter to tie a tie

and it's going to be more difficult if they're left-handed and you're right-handed for them to try and do it with their left hand. So they'll pick it up easier if they go against their instinct and learn it how you've taught with the right hand. Right. Yeah. Studies have shown that. Yeah. So you learn faster from watching somebody and then using the same hand movements that they do. Yeah. And that makes sense back in the, you know, with Tuk Tuk and showing his pal how to use the bone to smash skull. Right. You know, it's, if he picks up, his buddy picks up with his left hand, Tuk's going to shake his head. No. No, don't be stupid. Yeah. Use right hand. Or they're just going to, you know, everyone wants to fit in even back in the old days. Well, that's actually a

suggestion of why left-handedness is possibly not a little more prevalent among a certain age group today. Yeah. Because it was equated with being weird or off or crazy or whatever. Sure. And parents and teachers would force children to learn how to write with their right hand, effectively wiping out a lot of the left-handed population. Yeah. And just jumping back a minute, I wanted to mention something important that the whole correlation versus causation thing. Yeah. With the whole language center link, it's not necessarily, that's a correlation. They appear to be strongly linked, but no one is saying that because the language hemisphere is on the left side of your brain, that's causing you to be right-handed. Right. And again, the reason that they are linked

in a lot of scientists' minds is that speech and fine motor skills are basically uniquely human, almost uniquely human. And it's just a little, it's kind of like a red flag or a signal that they're both usually in the same hemisphere and they do seem to be connected. And one hypothesis for why they're connected, I thought was pretty smart, the idea that language, spoken language, emerged out of gestures, hand movements, which would require fine motor skills, right? But I don't have trying to do the too legit to quit thing, but the idea that language emerged out of that would suggest some sort of connection between the two, like maybe the fine motor skill section is the more ancient of the two, and then language evolved out of that. Right. But we also still

need our fine motor skills to eat with a fork and knife and everything, so it stuck around. Yeah. It didn't become obsolete just because we started speaking. Yeah, I like that theory. We did mention that this is largely uniquely human trait, but they have followed, they basically have been looking at our closest ancestors to try and figure a lot of this stuff out, although it did see some studies that said that like 30% of cats are left-handed because they'll go to swat things with their left hand. But I'm not so sure about that. Yeah, there's not only is it difficult, apparently, to test, or to attribute handedness to an animal, it's also difficult to attribute handedness to a person, because the idea of whether or not you're left-handed or right-handed, it's still

questionable, like if you write with your right hand, but you actually can write better with your left hand or something like that, which what are you? Yeah, is the one you're comfortable with or the one that you're actually better with? Yeah, that's a good point. But they have been looking at our primate ancestors since about the 1920s, and they have found patterns. Apparently lemurs and are more left-handed, and other prosimians, macaques and old world monkeys, for the most part, are evenly split, and gorillas and chimpanzees are about 35% lefty. But this is interesting, the more, as they say here, the more primitive the primate, the more likely it is to be a lefty, which goes in the opposite of the gene mutation. Right, it's the exact opposite. It implies that

we were originally left-handed as primates, and then as we evolved, we became right-handed, so therefore right-handed people are more evolved than left-handed people in some weird way. Yeah, so again, it's another inconsistency, and of course this is in primates too, that doesn't necessarily mean it's the same thing with humans. No, definitely not. But I mean, if you're looking at our ancestry and trying to figure out where handedness came from, you have to go pretty far back. Right. And that's a pretty good example of how this body of work or knowledge is very contradictory still. It's baffling. It's pretty awesome. Hey, Chuck. Hey. You sent me something about ambidextrousness. Yeah, I thought this

was kind of interesting from mental floss. It was just kind of my understanding that anybody who said, oh, I'm ambidextrous knew what they were talking about, but it turns out that's really just not the case. For the most part, it's a very rare condition, I guess you'd call it. Yeah, because I don't know if there is a strict definition for what constitutes being ambidextrous. Like a switch hitter and baseball doesn't necessarily mean they're ambidextrous. It means they've taught themselves to hit from the other side of the plate. If you notice as a baseball fan, you're never going to see a player that hits equally as well on both sides, like the great Chipper Jones here from Atlanta. Yeah. He favored one side of the plate, although he was a switch

hitter. He was a much better hitter. I think it was as a lefty and not as a righty. So that's not ambidextrous. No, someone who's taught themselves because it's a valuable skill in sports to be somewhat ambidextrous or in a lot of sports. But as far, I think writing is one of the things that they can look at as a clear indicator of which hand you're best at. And they say only about 1% can write equally as well with either hand. Right. So that's like super low. Apparently too. So this handedness and this lateralization of the brain and division of labor and all that has a lot to do with how your brain's connected. And apparently handedness is a part of that too. Yeah. So like for example, people who are ambidextrous are more likely to suffer from

schizophrenia to have schizophrenia. And it's not just ambidextrous people. Apparently lefties show a greater propensity towards schizophrenia. Something like 40% of people with schizophrenia are left-handed, which is a very high proportion considering the general population is about 10%. More than that dyslexia and stuttering as well. So lefties. Right. Which suggests that left handedness has an effect on how your brain is wired. Yeah. It's not just a simple, oh, my hand is, I use my left hand, my brain is otherwise the exact same as a right handed person. The brain does appear to be different. Yeah. In some ways, especially in the ways that it's connected. Yeah. We talked about synesthesia before, one of our favorite,

what do you call it? Not a condition, is it? Yeah. Is it? Sure. I always just think of condition as something that's derogatory. That's bad. Yeah. No. Like a malady or something. I mean, I think that falls under that one is one, but the other one isn't necessarily that one. So like a malady is a condition, but it sure isn't necessarily a malady. Right. Anyway, that's my long wind away of saying synesthetes are awesome. Yeah. And the rate of ambidextry in synesthetes is much higher and left handedness than in the general population. Right. So we have some clues here. Handedness has to do with how your brain is wired. And if your brain is wired in such a way that you are left handed, your brain is wired differently from

a person with a right handed brain, right? Yeah. And a lot of studies have backed that up and have come up with things like it's entirely possible that if you're a left handed person, you've got some advantages in life. Yeah. We'll talk about those right after this. I'm Mangesh Atikular and to be honest, I don't believe in astrology, but from the moment I was born, it's been a part of my life. In India, it's like smoking. You might not smoke, but you're going to get second hand astrology. And lately, I've been wondering if the universe has been trying to tell me to stop running and pay attention because maybe there is magic in the stars if you're willing to look for it.

So I rounded up some friends and we dove in and let me tell you, it got weird fast. Tantric curses, major league baseball teams, canceled marriages, K-pop. But just when I thought I had to handle on this sweet and curious show about astrology, my whole world came crashing down. Situation doesn't look good. There is risk to father. And my whole view on astrology, it changed. Whether you're a skeptic or a believer, I think your ideas are going to change too. Listen to Skyline Drive and the I Heart Radio app, Apple Podcast, or wherever you get your podcasts. So Chuck, one of the things that left handedness possibly bestows,

confers upon you as a benefit is the idea of thinking quicker to be able to process information more quickly. Yeah. They have done some studies on this. They did a couple of studies, one of which they sat down 100 people, 80 right handers, 20 left handers, and basically just showed them a computer screen with a single dot either on the left or the right side. And you had to press a button. It's just a speed test, basically. Right. Like which side is it on, left or right? Right. So if something shows up on the left side, I'm sure you have a clicker in your left hand and clicker in your right hand. You click the left hand clicker. But this is all happening very fast. That's right. And left handed subjects were

overall faster. In the other tests, they had to match up multiple letters that appeared in some cases on either side of the line and in other cases on just one side. And again, left handed were faster, but just at matching letters that were on both sides of the line. Right. Which I thought was interesting. Well, and that supports this idea that the brain, the fact that some left handed people's motor skills and language centers are on different sides in their brains, could make them talk more. The sides of their hemispheres of their brains are more connected. There's more white tissue where their corpus callosum is more efficient. It makes sense in a way, but at the same time, you're like, wait, that doesn't make any sense.

So it's kind of, this data should be taken and just locked away in a box until we understand the whole thing more. Because it doesn't really do a lot at this point. We don't know enough to make it fit. No. And it's actually kind of contradictory to some other stuff too, as far as handedness goes. Yeah, but they do say that if you're left handed, you may be like a better gamer. Yeah. Or a pilot because you're able to just process this quick information super fast. Right. Like rapid fire stuff coming at you. It also suggested too that language can be processed in both hemispheres among left handed people, which again would require a lot more connections between the two hemispheres, faster communication between the two, and hence quicker thinking. Yeah, and that in

the long run, as you age and your brain deteriorates, you may be in better shape as a lefty because your other hemisphere may be able to pick up that slack more easily. Whereas if you're just a dumb right-hander, you're just screwed. You're in trouble. And of course, this is proven. This is just, they're postulating here. Right. But I mean, it adds to this mystery. Yeah, you definitely have an advantage in sports in a lot of cases though. Yes, but not in the way that you would think. It's not necessarily because your brain is communicating, the hemispheres of your brain are communicating. It's more because your opponent is statistically likelier to be expecting you to be a right-handed person, to have trained against the right-handed

person. More practice, basically. Exactly. To be used to playing a right-handed person. Whereas if you're a left-handed person, they're playing you now, you're going to throw them off guard. Yeah. You're going to catch them off guard. You're going to be able to get the drop on them because they're not used to you. Whereas you, being a lefty, you're still statistically likelier to have played right-handed people. Right. So you know how to handle them. They don't know how to handle you. You're the wildcard baby. You win. You're Rocky. Yeah, Rocky was left-handed apparently. Yeah. And there's a bunch of sports figures in real life that were left-handed and apparently it's one of those things where they're disproportionately represented. Yeah. As

far as successful athletes go, compared to the population at large. Yeah. And I think a lot of times you'll hear about like MMA or boxing. Tennis is another big one because if you're used to playing righties most of your life, that left-handed server comes up there and it's different. It's weird. Right. And the difference is so pronounced that like if you are a pro tennis player or something like that or a pro boxer, you're going to train against a lefty before a before a match against the lefty. Yeah. You're going to do what you can to prepare yourself. Yeah. And I think Robert Lam wrote this on House the Forks, our left-hander's quicker, I'm sorry, better at sports. Yeah. And he also points out that through history,

this probably comes from like soldier training, mainly training and fighting and jousting and sword fighting and everything against other righties as well. Yeah. So a lefty would have a left-handed warrior might be more prone to be, you know, the great leader, like perhaps Alexander the Great. Right. Who was supposedly left-handed. What's weird though is if that had been the case, if humans have been left-handed and right-handed, the proportions have been roughly the same for the last 200,000 years. If you're a left-handed combatant, wouldn't then the proportion of left-handed people have grown over time because of natural selection? Because you have an advantage in battle or something like that. So therefore, the population of right-handed

people would drop in relation to the population of left-handed. Is it killed them? Exactly. That makes sense. And I remember... It does, but it hasn't happened. Yeah. I remember our podcast on castles like 80 years ago. Remember they built the staircases going on the right-hand side. I can't even... Do you remember how mine, you don't remember? Bendingly difficult that was for me to understand. Oh, no. Did you have a hard time with it? Oh, yeah. We had to re-record it, I think, twice because I kept getting it wrong. Yeah. We also got in trouble for a cuss word in that one, too. That was a dark day years ago. Oh, yeah. Yeah. But yeah, the castle steps would wind up on the right side of the wall

to give the advantage to the person higher on the stairs swinging a right-handed sword. Because obviously you couldn't swing a right-handed sword going up the stairs because the wall is on your right. But a left-handed combatant, the advantage taken away. Exactly. Even though you have the higher ground, because all of a sudden you're cutting the guy's knees off. You're cutting them off at the knees. Yeah. That hurts. It does. But also included with natural selection, too, is if there were any real disadvantages to being a left-handed person, or there were advantages to being a right-handed person, this population shouldn't have remained steady over that long of a period, too. I see what you mean. You know? Unless the advantage

isn't so great as to cause that natural selection to occur. Maybe. There are more U.S. presidents that have been left-handed. Yeah. More Mensa members for whatever that's worth. Yeah. Half. Half of the 12 U.S. presidents of World War II have been left-handed. Yeah. Whereas the normal population is 10 to 15 percent lefties, U.S. presidents of World War II has been 50 percent. And apparently in the 1992 campaign, all three candidates, H.W. Bush, Clinton, and Perot, were left-handed. Yeah. That's 100 percent of the population. Perot, man. He was fun to watch. He was. Dana Carvey was fun to watch doing Perot, too. Oh, yeah. And they say more musicians or musicians

are more likely to be left-handed, maybe. And it does run in families, even though identical twins can have opposite-hand preferences. Oh, weird. And there is, in the 1980s, there was a Harvard neurologist that said that lefties are righties whose brain centers in the womb change because of high testosterone. Yeah. So there's theories that we become handed in the womb because of something like that, or birth trauma, or some sort of trauma while we're in the womb. And that, yeah, it just adjusts the construction of our brains. Supposedly, a mother's age has an impact on her kids. Oh, yeah. That's crazy. Statistically speaking, a mother over 40 who gives birth has a higher likelihood of having

a lefty kid. Way higher, like 125% or something. Yeah. Yeah. Like, that's pretty high. Yeah. It's more than 100%. I don't even know what that means. Yeah. And then, I guess your hand preference emerges about by seven months. Oh, really? But then it's like set by age three. So before seven months, you're just flinging poop with both hands equally as well? Pretty much. Yeah. I read a story about a guy who found out as an adult that his mother had suspected he was left-handed when he was a baby. So she immobilized his left hand so that he would be forced to learn with his right hand. It's abuse. He didn't seem to take it like that, but he did. It came across like he felt like something had been kind of taken from him.

He said it also explained a lot that he was like so-so with stuff that involves his right hand, but he seemed to be better with his left and that he looked into it and that by doing that, which is very popular, like kids were forced to become right-handed through the 20th century, that you are basically making a less pronounced copy of the person. You're taking the original and making like a slightly dimmer facsimile of it by forcing their brain to reorganize like that. Interesting. Whereas they thought they were trying to give them an advantage to actually give them a disadvantage. Exactly, but I would imagine that if you did that to say age 18, and then all of a sudden started using your dominant hand that you were naturally born with.

It's all like spindly and weak. Right, but then once you train it to bulk back up, I would imagine your brain would be better off like that. It'd be fuller. Right, so continue the abuse. Right, until 18. Okay. Discontinue the abuse, and then bam, you got a super kid on your hands. Yeah, take your little old man, spindly hands and fingers. Build them back up. Mr. Show character. Remember, Titanica went and visited David Cross in the hospital. You know, they're getting back together, so that's exciting.

So PFT tweeted something, some picture. It's very exciting. The whole gang. If you want to know more about Paul F. Tompkins or Handedness or Mr. Show or any of that jazz, you can type that stuff into the search bar at howstuffworks.com. Since I said search bar, it's time for listener mail. I'm going to call this Christian Shoutout. Hey guys, started listening a few months ago and have already listened to about 160 episodes. Not bad. And by the way, we've mentioned this a lot, but if you're just on iTunes,

say, and you think, boy, these guys have got 300 episodes. 301. Yeah, we've got like, how many now? 700 and change. Yeah, 700 plus that you can find on our website, stuffyoushouldknow.com. Yeah, and as a little pro tip, if you go on to stuffyoushouldknow.com, aka the website with one of the worst searches in the world, just do control F and open up your web browser search and then type it in on our podcast

archive page. Oh, if you're looking for something? Yes, it'll bring it up. Don't search for it. Don't bother searching for it using our search tool on our site. We're working on that. Are we working on that? I hope so, because this is really bad.

Like, it doesn't bring up anything. Really? Yeah. Wow. That's pretty bad. And why is it even there? I don't know. I guess for looks. Blame. So getting back to this, we do have a lot of podcasts out there for those of you who don't know.

We have 700 plus. I forgot what we were talking about. He's listened to 160 episodes. His favorite thing about them is how you don't poo poo anybody's beliefs. I'm a Christian, so when I was very much so begrudgingly listen to your evolution suite, I was expecting to be mad. But to my surprise, I heard a very non biased view of evolution. I do believe in evolution, but it's a long story, by the way.

After many years of hearing creation of slam, people talk about evolution is a very pleasant surprise. So I just want to say thanks for putting your hearts, but not your opinions into that episodes. That is from Matt, very sincerely. We've been taking a task here and there. We try to do our best, Matt, to keep things on the level like that. But we are human and we do flounder here and there with that, but we try and we appreciate your kudos for that. Yeah, thanks, Matt. If you want to give us kudos, we would love to hear about that.

Or if you have any great stories that has to do with handedness, let us know. I'm tied to your waist till you're 18. As a baby, yeah. You can tweet to us at SYSKpodcast. You can join us on facebook.com. You can send us an e-mail to stuffpodcast.howstuffworks.com. And as always, join us at our home on the web, stuffyoushouldknow.com. During two decades in reality TV, Chris saw it all, and now he's telling all.

It's going to be difficult at times. It'll be funny. We'll push the envelope. We have a lot to talk about. Listen to the most dramatic podcast ever with Chris Harrison on the iHeart radio app, Apple Podcasts, or wherever you get your podcasts. We're going to use Hey Dude as our jumping off point, but we are going to unpack and dive back into the decade of the 90s. We lived it, and now we're calling on all of our friends to come back and relive it.