WE ARE ALL DESIGNISTS NOW:

Having trouble shutting down your computer? Can't stop refreshing your Facebook and Twitter streams? Did you close Reddit in your browser window ... only to open Reddit right back up again? If you're concerned that your Internet use is becoming a compulsion, you're probably right: New research suggests that our uncontrollable desire to click may be deeply rooted in human evolution.

"The Internet is not addictive in the same way as pharmacological substances are," cognitive scientist Tom Stafford at the University of Sheffield in the U.K. told Tia Ghose at LiveScience "But it's compulsive; it's compelling; it's distracting."

As Stafford explains, our love for the Internet is rooted in the fact that human beings, in Ghose's words, "compulsively seek unpredictable payoffs." The cognitive-reward structure offered by services like email and social media are similar to those of a casino slot machine: "Most of it is junk, but every so often, you hit the jackpot." This is a symptom of low-risk/high-reward activities like lotteries in general. As researchers found in a 2001 article in International Gambling Studies, systems that offer a low-cost chance of winning a very large prize are more likely to attract repetitive participation and, in turn, stimulate excessive (and potentially problematic) play. Although the stimuli are different (the payoff on the Internet being juicy morsels of information and entertainment rather than money), Stafford says that the immediacy and ubiquity of Internet "play"--i.e. being able to check your tweets or emails on your phone with no major transaction cost--only increases the likelihood that someone will get sucked into a continuous cycle.

Using the DSM as a guide, Dr. Kimberly Young defines "Internet addiction" as an impulsive-control problem with four distinct subtypes: cybersexual addiction, cyber-affair/relational addiction, net compulsions, and information overload.

"The Web's unpredictable payoffs train people much in the same way Ivan Pavlov trained dogs," Ghose writes. "Over time, people link a cue (e.g., an instant-message ping or the Facebook homepage) with a pleasurable rush of feel-good brain chemicals. People become habituated to seek that social rush over and over again."

The message of Stafford's research is clear: Your brain really wants you to click on all of those cat photos. "The next time you wonder whether you're spending too much time on Facebook or BuzzFeed or whatever, just remind yourself: You're wasting time because your brain wants you to," writes my former colleague Megan Garber at The Atlantic. "The Internet's charisma is a function not just of all the great stuff that lives on it, but also of humans' carefully honed survival mechanisms--mechanisms evolved long ago, in response to vicious enemies. We can't quit our cat videos, it turns out, because of ... lions."

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