When Northeastern Professor Ryan Cordell’s daughters approached him asking for a puppy, he made the move plenty parents do: he stalled, telling his children if they received one million Facebook likes, he would cough up the cash.

Cordell thought he was taking a safe, “when pigs fly” approach, admitting to The Atlantic he and his wife had plans to tell their children in the spring, “‘Hey, that was a really great project. Let’s go look for a dog. You did a great job.’ We would have gotten a dog eventually anyway–it was a delay tactic.”

The siblings skipped the wait, however. They created a Facebook page called “Twogirlsandapuppy,” featuring a sign that read: “Hi World. We want a puppy! Our dad said we could get one if we get 1 million likes. So ‘like’ this! He doesn’t think we can do it!”

Seven hours later, they did.

The joke was on Cordell, whose been studying what makes something go viral during his tenure at Northeastern–at least in the 19th century. The Atlantic writes:

[Cordell] and his colleagues, computer scientist David Smith and English professor Elizabeth Maddock Dillon, are currently mining the Library of Congress’s collection of 19th-century newspapers, using an algorithm that automatically finds reprinted texts. They’ve created an index of 45,000 such reprinted texts, and now they’re sorting through it to find out which pieces were the most viral, and identify qualities they share.

Of course, the times have changed, but what hasn’t changed are obvious characteristics that make someone more likely to click “share,” including  brevity, comedy, charm and “resonance with cultural values.” Cordell acknowledges the speed and reach of digital technologies, though, are on an entirely different scale and the immediacy has made virality easier to obtain.

Cordell intends to study his daughters’ project a bit more closely to better understand social graphs and how content spreads, but he first had to get them a puppy, which the family ended up adopting from the North Shore Animal League America. Just look at how cute the newest member of the family is!