What keeps people endlessly scrolling, swiping and streaming? Many of the same design techniques that engineered compulsive play on video slot machines have migrated into social media, mobile games and streaming services — and they pose particular risks for children.
In two recent court decisions, platforms were held liable for harming young users; those companies are appealing and dispute claims their products are addictive. Still, more than a decade of research points to a small set of interface and algorithmic choices that capture attention and monetize it. Cultural anthropologist Natasha Dow Schüll, who spent 15 years studying casino slot machines, describes these elements as a kind of “superglue” that keeps people on apps longer, costing them time, focus and sometimes money. Recognizing these features helps parents and policymakers judge how potentially harmful an app may be.
Schüll’s investigation began on the casino floor. In the 1980s and ’90s, the gambling industry intentionally redesigned slot machines into screen-centered, fast-play devices that could induce a “machine zone” or “dark flow” — a trance where players lose track of time and surroundings. Some gamblers stayed at machines for entire days. From interviews with players, engineers and industry insiders, Schüll identified four interacting features that made those machines so absorbing. Around the 2010s, app designers imported similar techniques onto phones and tablets.
1) Solitude
When interaction is strictly between you and a device, the social cues that normally signal it’s time to stop — friends, family, group norms — disappear. Apps nudge private, quiet use: think a child alone in their bedroom with a screen. Research links isolated use to higher risk of problematic engagement, where people continue using despite harm to sleep, relationships or wellbeing.
2) Bottomlessness
Content that never ends removes natural stopping points. Infinite scroll, autoplay queues and endlessly refreshing feeds erase closure. Without clear endpoints, users don’t feel satisfied and are driven to chase “just one more” post or video.
3) Speed
Shortening the cycle between action and reward increases total engagement. Schüll found that accelerating play on slot machines led to longer sessions; the same principle applies to rapid likes, swipes and autoplay video. Faster feedback makes it easier to slip into a flow state, blurring the boundaries between user and interface.
4) Teasing — being offered almost what you want
Perhaps the most powerful tactic is teasing: algorithms predict what you want and then present something tantalizingly close but not exact, encouraging continued searching. Over time users chase increasingly tailored content, convinced the next item will be the payoff. Neuroscience shows that this near-miss dynamic creates persistent possibility — a motive to keep going.
Together these features form a potent recipe for overuse: solitude removes external checks; bottomlessness removes endpoints; speed accelerates immersion; teasing keeps desire alive. Schüll asks students to rate apps by these criteria as a way to assess potential harm. Experts emphasize that children are especially vulnerable: developing brains, weaker impulse control and unsupervised screen time make them more likely to be trapped by this combination.
The crossover from casinos is not just metaphorical. Techniques refined to maximize gambling engagement were adapted to attention-driven business models, and advances like faster networks and sophisticated recommendation algorithms magnified their reach. The result is products engineered to create ongoing relationships with users rather than functioning as simple tools or occasional entertainment.
That has policy implications. Parents can reduce risk by limiting unsupervised access, setting clear boundaries, and talking with children about their habits and why certain features are designed to keep them engaged. But many researchers and advocates argue designers should also be held accountable and that regulation is needed to protect young users from manipulative features.
Michaeleen Doucleff holds a Ph.D. in chemistry and is a longtime science journalist, formerly with NPR. She is the author of the parenting book Dopamine Kids.