Why Are So Many Pro Athletes Lefties?

♪ INTRO ♪ Most humans are righties: people like me who use their right hands to write or… do football. But even though only 10% of people are left handed, 50% of professional fencers are lefties. In fact, there are lots of southpaws competing in top levels of sports, like boxing, tennis, and baseball, too. So, what gives? Do left-handed people have some sort of, like, good-at-sports gene that the rest of us don’t? Turns out, how certain competitive athletes rise through the ranks can mirror how populations of animals change as they duke it out for survival. Let’s say you’re a hungry house sparrow that has two main food finding behaviors: There are producers, who spend a lot of time and energy hunting for mealworms, or scroungers, who steal food from producers. If there are lots of producers competing with each other to find food and not that many scroungers, the scrounging sparrows have it easier. There are lots of sparrows to steal from and it doesn’t take a lot of energy to stay alive. But if there are too many sparrows trying to steal and few finding mealworms in the first place, the scroungers will starve, while the producers will be well fed. Basically, the frequency of a behavior determines how successful it is, and the more common the behavior is, the worse it is for survival. So ecologists call this a negative frequency-dependent model. This particular example shows how behaviors can change within a population of sparrows. Scientists also use this model to talk about how populations evolve over time because of selection, how animals with certain traits are more likely to survive and pass those traits on to their babies. Professional athletes can sometimes be modeled like animal populations because there are analogs for different generations and death. Some people win a lot and go on play at higher levels, while others remain at lower levels or stop playing. In 1-on-1 sports, like boxing or tennis, there’s direct competition between players, and success can depend on different traits, like how fast someone’s reflexes are, or which hand they use. So a sort of selection can come into play. Now, there doesn’t seem to be an inherent advantage to be left handed. They aren’t faster or stronger athletes. But they might do better as beginners in 1-on-1 competition sports because they’re less common. If you’re just starting out as a right-handed fencer, for instance, you have fewer chances to practice against lefties, so their movements might be a little less familiar and you might lose more often. Because there are so many right-handed people, left-handed athletes might be more successful early on, and rise through the ranks, which fits with a negative frequency-dependent selection model. At higher levels, though, the lefty advantage becomes weaker because the pools of athletes are more mixed. There are a lot of other factors at play, too. So, this model probably isn’t the only explanation for this pattern. But wield those left-handed scissors, or foils, with pride. It can be helpful. Thank you for asking, and thanks especially to our patrons on Patreon, who keep these answers coming. If you would like to submit questions to be answered, you can go to patreon.com/scishow. And don’t forget to go to youtube.com/scishow, and subscribe for more science in your subscription box every single day. ♪ OUTTRO ♪

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Reader Comments

  1. Abahrelghazali

    Where does the fencing info come from (and what's a 'professional fencer')? A few years ago, a friend and I went through the international fencing federation archive and recorded the handedness of the top 100 men's sabre fencers over 10 years, and found the number to be closer to 25%. Still higher than the population average but much lower than the 50% you cited.

    None of the reference links work.

  2. Septic Bile

    I don't know how well it translates to non combative sports,but I fence and fight. lefties have an advantage because there are less of them,so less lefties to train against. your first match against a lefty will be an awkward experience if you don't prep.

    edit: hey, I was kinda right! (handed)

  3. Shaun Kennedy

    My brother and I both do martial arts, and my brother is a south paw. As someone who had a semi regular sparring partner that was left handed, I would often take lefties by surprise. They would often comment that it was strange to go against someone who could compete so seamlessly with them and other right handers. Another not-as-uncommon-as-you'd-think situation that I witnessed with my brother more than once was this: he would take his stance and lead with a left handed attack as naturally as possible. His opponent would then block toward the right just as naturally… until halfway through the block. At this point the opponent realizes what a mistake they've made, and their eyes open in panic. Being in panic mode, their best practiced reflexes become super-charged, forcing their block even further in the wrong direction. As the south paw closes in, the problem compounds exponentially, until the righty (sometimes even an objectively better fighter) is entirely within the power of the lefty. Defeat becomes a slow, painful, and deliberate process. If one could die simply of embarrassment on the mat, this would have been the final chapter of very many objectively talented and skilled martial arts competitors.

  4. basketballkidforever

    I'm ambidextrous (: I swing with my left , shoot a basketball with my left, catch with my left , but throw with my right, & write with my right hand . Ayee

  5. rdizzy1

    In reality the percentage of lefties is higher than statistics show, due to many countries forcing kids to use their right hands very early on in development, and the brain adapting after a while.

  6. Vansh Arora

    My hypothesis is that lefties are forced to learn to play against/with right handed people, but that is not always true for right handed people. So as Hank said, lefties become better at a younger age.

  7. Janni Gulde Iversen

    Being a leftie training in a rightie world has it's advangetes. Like being able to switch in badminton to get a greater range 😛

    I might be a somewhere in the middle though. Write with my left, cut with my right and please do not ask with wich to eat. I won't remember how to properly hold the utensils as my right and left hands are basicly equals in that area 🙂

  8. Justa Bill

    I'm a martial artist and, even thoughh I'm right -handed I fight southpaw. This throws most other fighters off as my stance and movements are somewhat unfamiliar and confusing to both righties and southpaws.

  9. Alexander Truuvert

    As a fencer I can confirm this is true. When I joined there were no other lefties in my group, meaning I couldn't practise against them, and when I did come across them in competitiuons, the beadwork is very different, so any leftie dispensed with me easily. It's more balanced out but they're still harder to fence.

  10. jamham69

    This is especially prevalent in martial arts. Not necessarily lefties, but those who fight southpaw, have a considerable advantage. Its extremely difficult for the very best to find others at their level who aren't actually competing themselves and therefore make good practise partners.
    Those that do are normally stuck with only one or two training buddies and the maths says hardly anyone gets lefties. So lefties dominate competitive martial arts.

  11. Jeffery Rowan

    Oddly enough left-handers often have difficulty playing other lefties too. Same problem, so few of them to compete against.

  12. James Goddard

    I'm left handed and I've found people who I've spared with( reenactment) who are right often find it difficult to adapt the my left handed style. Why are left handed people called "south pawed" where did the term come from ?

  13. kabob21

    Pretty much the Federer-Nadal rivalry in a nutshell. Federer might have more Grand Slams and have achieved much more in his career (especially on faster surfaces/away from clay) but his righty backhand going into Nadal's insanely torqued, spinny forehand has led to a lopsided head-to-head record in Nadal's favor.

  14. Les Bray

    Very simple to answer though 2 very different questions. People are atheist because they have bee afforded the opportunity to express knowledge from reason, some are lefties because they're tendency toward well meaning ideas is greater than they're power of objective reasoning.

  15. Rob Wilson

    This phenomenon is why pocket picks and cheese exist in e-sports, and likely why rare/unusual techniques (knuckleballs, etc.) are more common in competition.

  16. FluteGeek

    Aren't four out of those five hands at 2:54 right handed. The wine glass is the only lefty.

    "Handle those left handed scissors with pride" …

  17. delancyj67

    Another fact: Since the 1980's only two US presidents have been right-handed. George W. Bush and Donald Trump. The world is too complicated for right-handers to manage properly.

  18. Spencer Williams

    I remember the first fencing tournament when I had to go against a left handed fencer. My parries and attacks didn't work because everything was in reverse and I had no idea what to do. It goes to show that the body learns specific movement patterns which can be thrown off when conditions vary.

  19. Eliza

    I have been asking exactly this question, with exactly this explanation in mind, for months. I even used fencing as an example when trying to explain my theory. No one I spoke to could either confirm or deny the idea that most people were right-handed and used to competing against right-handed opponents so left-handed people would have an advantage over right-handed people in one-on-one competition… until now! Thank you for these doses of science that keep me sane and entertained!

  20. Dennis McConnell

    I hope everyone knows the REAL reason there are so few left handed people. Talk to the Catholic church, they forced left handed people to use their right hand because they thought it was a sign of the devil to be left handed. Before anyone starts screaming I know for a fact this is true because I am left handed and went to a catholic school and had to personally deal with it. Also before you making some stupid comments about how catholic schools aren't that common they are FAR more common in the rest of the world then they are in the US. Ok troll away I know people are gonna have a melt down about this comment, if you can't handle the truth you probably shouldn't be looking for science shows on youtube or reading the comments of said shows.

  21. OddBoyy

    How dare you! I am a saber fencer, not a foil. and what about epee? (I'm kidding btw) Also I suck at fencing, and you guessed it, I'm a righty

  22. Heta Lehtonen

    Are you sure those are house sparrows in the animation? They look a lot more like Eurasian tree sparrows to me. (And yes, I know they're not real, but it's SciShow, so I thought things like this matter.)

  23. Independientefan

    Only an American would play football with his right hand. (Or a goalkeeper I suppose.) You play football with your feet!

  24. BrotherWoody1

    The great example that comes to mind is Rafael Nadal who was born a righty but as a kid, was trained as a lefty. As of June 9th, he's still in the mix for his 10th (!) French Open. He's the only lefty in the final four.

  25. ShadowDrakken

    I've always wondered why there's so many lefties in engineering fields. When I was with USACE, there was a disproportionately high number of lefties. Since it's all mental tasks the negative frequency dependent selection model doesn't work unless there's something else lefties have an advantage in.

  26. Col of Cthulhu

    Leftie here. I don't know why this is either. I've always been fairly lazy, very rarely do I work out (Not really at all, actually), but I can still run the 100m sprint in 10.3 seconds.

  27. Patrick McCurry

    The real question is why are so many humans right handed? The vast majority of animals have an equal balance between left and right fore(paw/claw/tentacle) preferences. So why do some species show such an unusual imbalance?

  28. BDAShadow1

    I don't see the logic in the second bird example; where there are too many scroungers and few producers the scroungers will obviously starve, but the producers will still starve as well because we just established that they are getting picked clean by the abundance of scroungers. I think it needs to be clarified that the producers will only begin to bounce back after the scrounger population falls.

  29. Everest314

    Not many people "do football" with their hands … whether right or left … (okay goalies, but the use both hands…)

    … Couldn't resist … 😀 (Calling a game football where you are only allowed to use your hands 99% of the time…)

  30. SkyreeXScalabar

    Also in tennis if you are a lefty like nadal, they can hit a forehand crosscourt into the righty backhand which is their weaker side

  31. ofircahalan

    It would be interesting to check the statistics for fencing and boxing against a sport that doesn't involve your hands particularly much, like cycling or track, and see if there is still a disproportionate amount of lefties. I don't see why there would be more lefties in cycling, but if there were then I wonder how you could explain that.

  32. Psychology Stud

    This is true in wresting. In highschool, knowing how to do techniques the left handed way gives you an advantage. In college, most athletes train both sides, so not knowing how to attack and defend left handed techniques puts you at a disadvantage and knowing it only keeps you on par with the others.

  33. Gavin Bednar

    i am actually a former fencer and lefty, at beginner levels people just seem like they are throwing exposed area at you, but that stops pretty fast at higher levels of competition

  34. white liberals are assholes and jerks

    i first thought judging by the title that he was on about white liberal lefties🤣🤣🤣🤣🤣

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