The World Series is the most important thing that can happen to a baseball player, and it is happening now to a bunch of them. You may have noticed that many have been conspicuously chewing things the entire time, including Yankees left fielder Alex Verdugo, who was blowing a bubble while misplaying a ball in the very first inning of Game 1.

The constant chewing is one of the weird things about baseball. Casual viewers respond to it by saying, “That’s weird.” Baseball fans respond to it by saying, “That’s just how it is in baseball.” And both statements are true. The chewing isn’t happening only during downtime in the dugout. Players with pizzazz blow bubbles while catching fly balls or hitting home runs. Outfielders are the most frequent chompers, but even players in the much-busier infield will sometimes spit out a shell in the middle of the action, or gnaw on a toothpick. Once in a while a player will even be tempted by the ballpark snacks that fans are eating in the stands. My question is, Why?

I’ll be honest: I care about this question because I love baseball, but also because I have a lot of dental problems and can’t personally imagine putting Dubble Bubble in my mouth ever again. I became fixated on the issue following a game this June between the New York Mets and the Texas Rangers, during which pitcher Max “Mad Max” Scherzer was shown in the dugout laughing maniacally and heckling his former teammates, while also munching on sunflower seeds so aggressively that it looked as though he were munching off bits of his own teeth. I can’t tell you how distressing this was.

The chewing habit is unique to baseball, America’s best sport. You don’t chew anything while playing football because you’re probably wearing a mouth guard so that you don’t accidentally bite off your own tongue. You wouldn’t want to run around on a basketball court with something in your mouth, because you could choke on it. Even golfers and soccer players, who sometimes chew gum, do not commonly have pockets full of loose seeds, or barter with children for bags of Nerds Gummy Clusters.

Baseball isn’t merely amenable to snacking; the game is arranged around it. Other sports have locker rooms and clubhouses full of snacks, but baseball has a dugout where players sit during the game and have continuous access to those snacks. A baseball player can even keep snacks in his pockets on the field, Brian Purvis, the head of the Chattanooga branch of the Society of American Baseball Research, told me. Then he added: “I would be curious why baseball uniforms even have pockets?”

One question at a time!

As for why all of this chewing is happening, I solicited input from dozens of baseball enthusiasts including historians, journalists, former players, sports nutritionists, and miscellaneous other interested parties, such as the publicists for various candy companies. Some of them acknowledged that it’s weird. Others told me, “That’s just how it is in baseball.” And more than a few had theories to explain the practice—somehow, only one mentioned Freud.

Obviously, in the old days, baseball players chewed a lot of tobacco. This was partly on account of players’ societally average addictions to nicotine, partly on account of its stimulating and supposedly performance-enhancing effects, and partly on account of their habit of slobbering tobacco juice onto the baseball so that it would be darker and harder for the opposing team to see and hit. The slobbering (but not the chewing) was disallowed in 1920 by a rule change against “ball defacing.”

For many decades after, children watched as players smoked cigarettes in dugouts and visibly chewed dip while batting. They watched as players would, occasionally, choke on their tobacco wads and delay gameplay. The wads themselves grew even bigger and more visible in the ’80s, when players realized they could wrap their chewing tobacco in bubble gum to hold the leaves together. Tobacco was not denounced by Major League Baseball until the ’90s, when it was banned first from minor-league stadiums and then from the annual All-Star Game.

But the habit was a sticky one, and hard to get rid of entirely. If tobacco was going out of fashion, it would have to be replaced, in the words of the internet’s favorite baseball movie, by re-creating it in the aggregate. Gum could replace the chewing; seeds could replace the spitting. Hence, a 1997 headline in the Sarasota Herald-Tribune: “Chew Tobacco’s Out, but Ballplayers Young and Old Agree That, Whether It’s Bubble Gum or Sunflower Seeds, You Need to Jaw on Something.”

[Read: Goodbye, Coliseum]

Tobacco is now banned from many Major League stadiums, and it was mostly banned from the sport of baseball itself in 2016, not long after Hall of Famer Tony Gwynn died from oral cancer. Bubble gum and sunflower seeds remain as popular as ever. Dodgers first baseman Freddie Freeman, who has been in the Major Leagues since 2010, doesn’t chew tobacco, yet he will dump an entire bag of seeds into his mouth at one time. Yankees pitcher Nestor Cortes, who made his debut two years after the tobacco ban, has said that he chews “at least 30” pieces of gum per game.

If they aren’t chewing for the high, what’s the point? Other claimed effects came up here and there during my interviews. Some people mentioned that baseball is a game that involves sliding in dirt, and that chewing gum can help you keep the taste of the field out of your mouth. Ken Clawson, a former minor-league baseball player, said he’d read somewhere that the habit gets more blood flowing to the head and can therefore help with focus. SABR’s Purvis thought chewing had to do with timing: “Something about the rhythmic moving of the mouth allows them to set their internal metronome.” Sure!

When I got in touch with John Thorn, the longtime official historian of Major League Baseball, he was unimpressed by the batch of theories that I’d gathered to that point. He said that eating is just a way of dispelling nervous energy. “The calming effect of chewing tobacco was largely in the chewing, not in the messy weed,” he told me. “The charm of sunflower seeds may be entirely attributed to Freud.”

In other words: The oral fixations relax the players, who are like so many giant, strong, and handsome babies sucking their thumbs.

Anxiety and dirt in the mouth aren’t the whole story, though. When looking to explain anything in American life, one should always look at the commercial interests involved—Big Chewing, in this case.

John Thorn walked me through the history of baseball’s relationship to the great oral-fixation industries. Lou Gehrig, Ted Williams, Joe DiMaggio, and other baseball greats appeared in ads for cigarettes, which sometimes implied that their elite athletic performance was enabled by their choice of smokes. Chewing gum came in later: Beginning in the 1920s, William Wrigley Jr., the founder of the Wrigley Company and the owner of the Chicago Cubs, allowed numerous radio stations to carry Cubs games, because this would also serve to advertise his gum. His son and successor, Philip Wrigley, provided gum to players in the clubhouse (and, incidentally, referred to his product as “an adult pacifier”). Other entrepreneurs spread gum throughout the league. Sy Berger, of the Topps trading-card company, wooed players to license out their likeness by giving them free stuff, including Topps’s hit product, Bazooka bubble gum.

Gum and baseball cards were such a natural pairing that, eventually, kids could buy a pack of gum with a baseball card in it, or a pack of baseball cards with a stick of gum in it. In 1975, the TV broadcaster and former Major League catcher Joe Garagiola hosted a bubble-blowing championship. The contest was sponsored by Bazooka, and the winner, the Milwaukee Brewers’ Kurt Bevacqua, was honored with a special baseball card. Soon after, the debut of Big League Chew gave kids an opportunity to emulate professional baseball players by chewing gum that was shredded to look like tobacco—the idea being that money could be made in preventing kids (and adults) from taking up a truly disgusting habit while continuing to channel their dreams to baseball. (They could mail in wrappers to receive a World Series–inspired ring.)

[Read: Moneyball broke baseball]

Candy companies have found ample opportunities in baseball ever since. Turk Wendell, a former relief pitcher for the Mets who is best remembered by the baseball-viewing public as the guy who wore a necklace draped with claws and teeth, was known to chew black licorice on the mound. He also received free candy all the time. “Brach’s candy in Chicago would FedEx me whatever I wanted,” he told me. “Any kind of candy—they would FedEx it to me on dry ice so it was fresh.” Today’s young players get excited about candy collaborations. The Yankees’ baby-faced shortstop, Anthony Volpe, used a Dubble Bubble–themed baseball bat in a game this year. The Mets’ baby-faced third baseman, Mark Vientos, wore cleats made by Adidas in partnership with Haribo, the German candy company whose gummy bears often appear in modern baseball dugouts.

Chewing seeds, which also goes back decades, is a somewhat less commercial custom. Reggie Jackson, who made it cool to chew packaged sunflower seeds in the 1970s, suggested that the nutrients provided by his habit could help prevent pulled muscles. “Mr. October may have been on to something,” Corey Tremble, the director of minor-league medical operations for the Texas Rangers, told me. The seeds are salty, and sodium is one of the main electrolytes lost through sweat. Chewing them during a game may work “to keep our muscles healthy and firing properly.”

Of course, there are a lot of other ways for players to accomplish the nutritional task of “consuming salt.” Many foods and drinks are salty, including—as Tremble noted—the cups of Gatorade that those guys are always swilling in the dugout. And a 1996 Wall Street Journal story about in-game sunflower seeds said that chewers were showing off their “tooth-tongue coordination” and that they stood in awe of Jackson not because his muscles weren’t cramping but, as one pitcher told the newspaper, because he “could eat ’em and spit the shells like a machine gun.”

In the process of reporting this story, I emailed 66 members of the Society for American Baseball Research, some of whom forwarded my question about chewing to still more members of the Society for American Baseball Research. The total number is unknown to me, though I received more responses than I could possibly manage.

Warren Simpson, of the West Texas chapter of SABR, got in touch to share his theory. Simpson is part of the Vintage Base Ball Association, an intriguing body that plays baseball in antique uniforms, and according to the rules of the late 1800s. In this league, it is still legal to throw spitballs, which is why Simpson himself started chewing tobacco in 2001. (He has since stopped.) He thinks chewing persists in baseball purely as tradition. Younger players chew because they think that’s what they’re supposed to do. “It’s part of what you believe is the culture,” he said.

[Read: Americans don’t really like to chew]

It’s true that baseball people are obsessed with tradition, and that kids will try to imitate their heroes. The retired center fielder Lenny Dykstra said he chewed tobacco because he’d grown up watching Rod Carew chew tobacco. Simpson told me that when he was a kid, everyone wanted to make basket catches like Willie Mays, or to be a switch-hitter like Mickey Mantle. In Simpson’s case, he wanted to get hit by a lot of pitches like his favorite player, Ron Hunt, who had set the Major League record for doing so in 1971 and famously said, “Some people give their bodies to science; I give mine to baseball.” They are not always valuable life lessons that you are learning from these idols, Simpson acknowledged. “It might have been better if he was blowing bubble gum.”

Baseball’s chewing tradition may also intersect with its long history of strategic rule-breaking. Baseball fans still gossip about which players might be flouting the tobacco ban. One of my favorite baseball players, Jesse Winker, is constantly eating Tootsie Rolls, even while running the bases—even while engaging in arguments with opposing players. I think Winker is chewing Tootsie Rolls just because he likes them, but it’s certainly true that having Tootsie Rolls or any other brown and waddish foods available in baseball dugouts gives cover to anybody else who might still be chewing tobacco. Tootsie Roll Industries, which once promised to award 1 million Tootsie Rolls to whoever scored the millionth run in the history of Major League Baseball, did not respond to my questions. Neither did the league.

That said, baseball is also a baffling sport played by fastidious people with numerous eccentricities and superstitions. Turk Wendell told me that he started chewing black licorice on the mound while he was in college. When his young teammates spat tobacco juice on his shoes, he needed a way to spit back without picking up a tobacco habit himself. “I thought, Well, I like black licorice and it looks like tobacco so it looks like I’m pretty cool,” he said. (He was chewing not-tobacco to cover up the fact that he wasn’t really chewing tobacco. This inverts the Tootsie Roll theory laid out above and also proves its feasibility.) Whatever his original motivation, Wendell got into chewing licorice, and then he never stopped. Wendell also liked to brush his teeth between innings. He did that for the first time because he had a bad taste in his mouth. (Was it dirt? I forgot to ask.) Right after, he struck out three batters. “Once you do something and you’re successful, you keep doing it,” he said.

If this is true for Wendell, perhaps it’s true for baseball on the whole. Once you’ve started chewing, how do you kick the habit?

I bet you’re still waiting for me to give the most obvious explanation for baseball’s chewing: The game is boring. Putting something in your mouth is something you do when you’re bored.

Fine. I’m a baseball fan, and I was inclined to dispute the premise, but even baseball players are partial to this theory. Wendell told me that he chewed in part because the games were so monotonous. So did Trevor May, a former pitcher and current media personality; he said that chewing sunflower seeds and gum is “the equivalent of watching a bad Netflix movie while you fold laundry.” Joe Nelson, another former pitcher, said that baseball is “incredibly boring.” Relief pitchers, in particular, spend much of the game out in the bullpen, separated from the action, he told me, and that “can get exhausting, mentally.” To chomp or spit is to stay awake and stay ready.

This makes sense to me. Agatha Christie used to eat apples in the bathtub whenever she was having a hard time working out her elaborate murder-mystery plots. You do whatever it takes to put your brain in your body.

Here I think it’s important to note that Major League Baseball prohibits the use of smartphones during games. Players in the dugout will sometimes watch footage of their at-bats on a shared iPad, leading fans to joke that they’ve been “rewarded with screen time.” But, generally, the players are more bored than you’ve been in years! You don’t remember what it’s like to be that bored. Maybe that’s why you—and I—might think all the chewing that baseball players do is weird, whereas the fans of prior generations might have understood it to be normal.

Time expands during a baseball game, and players have only what’s in their skulls to keep them occupied. “Baseball is a ponderous game with plenty of room for pastimes within a pastime,” Clayton Trutor, of the Vermont SABR chapter, told me. The snacks are raw materials. You will see players build little towers out of gum or use it to adhere a paper cup to an unsuspecting teammate’s hat. Baseball fans were tickled this year when Seattle Mariners pitcher Luis Castillo placed his sunflower seeds in the dirt in an ornate arrangement that possibly represented some kind of message to extraterrestrials.

“Baseball is a stop-action sport, and in that regard it permits not only such activities as bubble-blowing but also reflection,” Thorn told me, “and this is why baseball is the game of literature.” It was a little bit of a non sequitur, but I knew what he meant. Baseball is the subject of a good deal of classic American writing. And baseball players—though it may not always seem this way—are living the life of the mind. This is why they chew.

Fans are also in their heads. Thorn suggested that baseball’s open, airy nature is the reason that I, as a viewer, would even notice that players are chewing all the time. Arguably, watching baseball is making me a more observant and curious person.

My next questions are “Why do baseball uniforms have pockets?” and, relatedly, “Why do baseball players wear belts?”