Kariel, 68, an accountant in Houston, was also thinking about his father, who had died two years earlier, at age 92. In the last years of his life, his memory had slowly dimmed. “If there’s anything that I can do to keep my mind as sharp as possible, I will do it,” Kariel recalls thinking. “So that was, either consciously or subconsciously, a reason for me to start doing this.”

After conquering his first Wordle—barely!—he felt a rush of victory and posted the results on Facebook. Today, Kariel’s Facebook is mostly a daily diary of his 700-plus Wordles, with a few “Go Texans!” thrown in during football season.

Wordle is kind of like the love child of Wheel of Fortune and hangman. You get a maximum of six tries to guess a five-letter word. Kariel has also started playing Connections, another New York Times game, which asks players to group four words with similar themes. (They can be mind benders: (1) What do ancestry, broth, cattle and merchandise have in common? (2) How about Capitol, Faith, foot and mole? See below for answers.)

Like Kariel, many of us think that in some vague way, puzzles are like a daily vitamin for the brain, a tool for staving off decline. An entire “brain game” industry peddles the notion that by doing its daily puzzles, all sorts of measurable brain benefits will emerge. Whether or not puzzles can actually prevent dementia, or at least make you sharper, smarter and wiser, has confounded researchers for decades. But when it comes to the jigsaw puzzles, crosswords and word finds we grew up with—as well as the latest online craze—researchers say they can indeed help your brain. Just not in the ways you might think.

Though it would be great if scratching out answers on a crossword or pecking them out on your phone could make a significant impact on your dementia risk, evidence suggests “they’re not enough,” says psychology researcher Jennifer O’Brien of the University of South Florida.

O’Brien studies “brain training,” using computer programs that require you to process incoming information and make decisions. She leads a $44.5 million study called PACT, for Preventing Alzheimer’s with Cognitive Training, funded by the National Institute on Aging. The study is enrolling 7,600 volunteers 65 and older. It involves a variety of computer-based games and will track cognitive changes. But these tools have more in common with video games than crossword puzzles, O’Brien explains.

Even if solving the daily Wordle or your favorite crossword won’t protect you from age-related cognitive decline, your brain still gets benefits from the exercise, says Michael Vilensky, clinical assistant professor of psychiatry and behavioral health at Ohio State University in Columbus. That aha moment when you get the answer can trigger a tiny burst of dopamine, one of the key chemicals involved in the brain’s reward system—the neural circuitry that makes us feel good from things such as sex or chocolate. “That pathway is very much the same as some of the other pleasure pathways,” Vilensky says.

A shortage of dopamine is one of the hallmarks of Parkinson’s disease, and dopamine also plays a role in sleep, mood and pain tolerance.

We humans are programmed to want to satisfy our own curiosity, says Chantel Prat, professor of psychology, neuroscience and linguistics at the University of Washington, who has studied how the brain functions as people solve riddles. Studies have posed trivia questions to people while they are in brain scanners, then watched how the brain responds when tantalized about the answers. “The same circuit responds if you put a hungry person in the scanner and show them pictures of different kinds of food and say, ‘How much do you want a candy bar or a cheeseburger?’” Prat says. Solving a puzzle gives us a hit of satisfaction.

The emphasis on brain training and possible cognitive boosts overshadows what puzzles really are all about, and that’s stress relief, says Marcel Danesi, professor of semiotics and linguistic anthropology at the University of Toronto and the author of several books on puzzles. “When you start a jigsaw puzzle, all these pieces scattered all over—that’s chaos,” Danesi says. “You put it all together into the image, the solution to the jigsaw puzzle, all of a sudden, you feel accomplishment.” The chaos dissipates. “And temporarily you have order.” That’s why many popular puzzles show scenes of retreat—a beach, a cozy chair by a fire, a Monet-like spring garden.

So often in life, problems don’t have a clear solution, Ohio State’s Vilensky says. “The cool thing about a puzzle is you can solve it. There’s an answer. There’s something complete.”

The main reason science has had trouble figuring out the exact benefit of puzzles to any particular person is because people are complicated, and some things are hard to capture in an experiment, says Aaron Seitz, professor of psychology at the University of California, Riverside, where he runs the Brain Game Center for Mental Fitness and Well-Being.

“Most of these studies are overlooking what is probably the biggest benefit of puzzles,” Seitz says. “Puzzles are one kind of a mental break during the day that basically helps people switch between activities. The studies probably are not measuring the extent to which the puzzles help people relax and shift focus.”

A change of focus is one reason why crosswords first became popular decades ago, says longtime puzzle author and editor Stan Newman, who estimates he has edited more than 1 million crossword clues. “It was thought that giving people a gentle challenge on a Monday would help get their brains in the right mood for the coming week,” says Newman, who edits AARP’s daily crossword and Brain Games in AARP The Magazine. As the week progressed, so would the difficulty of the puzzle—and the feeling of accomplishment. “The higher up the difficulty mountain you climb,” he quips, “the better the view.”

He says he believes that regularly working crosswords enhances creativity. Some of the hardest crosswords require you to turn a clue on its head. It’s not so much about getting the answer by rote recall—like knowing the capital of Croatia—but in figuring out the puzzle maker’s tricks; for example, realizing the clue “Fed people” isn’t about eating, but the Federal Reserve (3). “I truly believe that working out difficult puzzles of any kind, though crosswords are the one I know the most about, can improve your creative thinking for real-life situations,” Newman says.

We are born with a need to play, but Thomas Henricks, a professor emeritus at Elon University and author of Play and the Human Condition, says that working a puzzle is distinct from other kinds of amusement. Games allow for individuality and self-expression. But most puzzles only have one solution; to solve it, you enter the world of the puzzle maker, like an explorer of someone else’s mind.

“As explorers, we build ourselves by our discoveries, even if these are territories settled long ago,” Henricks wrote in a 2022 essay in Psychology Today. “Sitting quietly in a favorite chair, we sense our connection to others.”

Since the advent of online games, puzzles have another immeasurable benefit: social bonding. Wordle, for example, was played 4.8 billion times in 2023. When Mark Kariel posts his daily Wordle, he knows that regardless of how many attempts the answer took, he will get a “well done!” and likes on his post from a dedicated band of Wordlers. And there’s the shared experience of doing it with his family and friends, including the day—July 4, 2023—when both he and his son solved the Wordle in one guess. (The word was “irate.”) Kariel and his daughter, who lives around 45 minutes away, will sometimes get on their phones and play Word Hunt through a game app they share, looking for hidden words inside a grid of letters.

That may be one of the biggest benefits of all. One place where the science is clear is the link between cognitive decline and social isolation. In 2020, the National Academies of Sciences, Engineering, and Medicine reported on data that estimated that older people who report chronic loneliness and social isolation have a 50 percent higher risk of dementia. “If you’re part of a community that is playing these games, and you are reinforcing each other, in addition to the dopamine, you’re also forming community bonds and social support,” Seitz says.

Which is one reason why Kariel isn’t going to stop his morning puzzles anytime soon. He understands that they may or may not do much for his brain in the future. But for a few moments, they provide a small bit of joy in the present.