In 1948, when Diane Howard was 4, she was learning to play ring-around-the-rosie.
In 2004, when Christian Magnuson was 4, he was teaching himself to install games on his dad's computer.
On Wednesday, Howard, 71, sat in a classroom where Christian, 16, was the teacher. His class: an introduction to smartphones for residents of Westminster at Lake Ridge, a retirement community in Prince William County, Virginia, United States. Christian began volunteering at the facility a year ago, helping at Tuesday night sessions where people could come with tech questions.
He noticed that plenty of them had smartphones - often gifts from children or grandchildren - but few knew what to do with them.
"They have self-taught themselves, to a degree," he said. "Unfortunately, that degree is they have taught themselves how to turn on their phone."
So a few months later, Christian started a smartphone class for them. He is on his fourth session, with classes on basic and advanced smartphone use, apps, and photos. Some of the facility's staffers have signed up, too.
"Because we didn't grow up with it, it's a little bit scary," Mary Ellen Saville, 69, said on her way to class. Especially the notifications about updates. Should she trust them? Would they charge her money? "I would like to know if there are any particular danger zones."
Carol Smiley, 80, said that in the year since getting her iPhone she had used it for "making a few calls, occasionally playing a game of solitaire. And I did do a jigsaw puzzle on it. But I don't know how to text."
It's a great way to win a bet. You don't have to have a stack of encyclopedias all the way up to here.
She came armed with a small silver stylus capped with a soft black nub - a device many at the facility rely on for smartphone use. "The letters are too small," she explained.
Standing before the roomful of people who are old enough to be his grandparents, Christian clicked his phone's home button. A giant image of the phone's display bloomed on a screen, and he began the process of demystification - along with a little teenage humor.
"See, it says the time and the date - 1:09, Wednesday, March 2. And you can change that if you want to, if you want to pretend you live in a different age."
The little airplane? The crescent moon tilted to one side? The tiny lock encircled by an arrow? Each has a purpose. And that spooky voice that rises up out of nowhere? That's Siri; she can be helpful if you give her a chance.
"It's a great way to win a bet. You don't have to have a stack of encyclopedias all the way up to here," Christian explained, demonstrating how to ask Siri a question. "It's just like having your own secretary, back when you were working. You now have a smarter one, and it doesn't cost you a penny, aside from what you paid for the phone."
By the end of the 90-minute session, the students knew how to take selfies, send text messages, change their ringtones and ask Siri the meaning of life (the answer was chocolate).
They also came away knowing about uses they had never considered. Like the emergency medical information they can enter into the phone, which ambulance crews can see without knowing the phone's security code. Or the exercise app that shows how many steps they've taken that day, and how many flights of stairs.
As a teacher, Christian, who has lived in the Pacific Islands and Germany and is home-schooled, exuded confidence. But it wasn't always so.
When it tries to spell-check my English words and I say 'No, that is what I wanted to say,' it drives me crazy.
The first time he taught the class, "he was scared, worried," said Mike Swain, a resident who runs the facility's IT committee. "After the first two hours, he said, 'That is the worst thing I've ever done.' I said, 'Christian, that's the best class we've ever had.' Because when they walked in they were holding them out in front of them like they were snakes getting ready to bite them, and at the end they were holding them close, talking to each other on the phones. . . . I don't care how much you learn, but if you're feeling better about it when you walk out the door, that's the goal."
Before Christian started teaching there, Swain said he was advising many residents not to use their phones.
"Some of them were not capable of using it. They have tremors, so that screws up the swipe. Their eyesight's not so good, their hearing's not so good for all those sensors. We were advising them to put them away because it was making their tummies hurt."
Now, they ask Siri to settle disputes at the dining table, like, When was the last time the Army won the Army-Navy football game?
Christian, who got his first phone at 8, says around 30 is the age where he sees a divide between those who instinctively get smartphones and those who need to be taken by the hand.
"There are people, say like my parents, who remember the first Mac coming out. They have a hard time," he said.
But even the old-timers are getting hip to what's cool. Last year, many were interested in learning Facebook. Now, they're asking about Snapchat and Instagram, because their grandchildren use them. Christian works with them on Instagram but tries to dissuade them from Snapchat because it is more complex and existentially problematic. "To a lot of people it's confusing. Why would you send something that's going to disappear and you'll never see it again?"
Howard was taking the class for the second time. After the first time, she surprised her grandchildren by FaceTiming them. They were impressed, "and then they held the dog in my face most of the time." She has also embraced Pandora, while out driving with her husband (who can't hear the music, so she gets to decide what plays).
One of the things he made us realize is that you can't break it, that you can hit buttons and it's OK.
Smiley came out of the class relieved to know the phone was hardier than she had thought. "One of the things he made us realize is that you can't break it, that you can hit buttons and it's OK."
Smiley's grandchildren tease her because she still has an old-fashioned telephone attached to her wall. Howard's grandchildren didn't even know what a pay phone was when they encountered one at the airport in Phoenix.
Still, the women said, there are things that old-fashioned humans continue to do better.
"I'm picky about spelling, I grew up in a family with very good grammar and spelling," said Saville, a retired administrator for a nonprofit group. "When it tries to spell-check my English words and I say 'No, that is what I wanted to say,' it drives me crazy."
And Smiley, a retired church musician, observed that the art of texting and conversing through emoji seems to come at the expense of another art, one that every elementary student used to learn.
"I was astonished by my grandson - he's 22, 23, he graduated from George Mason University and is going into a master's program. But my son said: 'Mum, you can't write to him in cursive. He can't read it."