Research links slot-machine “dark flow” features to addictive design in apps. Experts warn children need stronger protection and support.
A growing body of research suggests the pull that keeps people glued to slot machines is not confined to casinos at all. The same mechanics—now common in phone and tablet apps—can create a “machine zone” or “dark flow,” where time and place blur, and leaving the screen feels harder than it should.
More than three decades ago. Elizabeth Schüll began a mission focused on understanding how these games exert a magnetic effect and what specific elements might prevent “flourishing. ” or healthy engagement.. Over 15 years. she studied how video slot machines work from the inside and interviewed people across the industry. including marketers. mathematicians. software engineers. and executives. as well as frequent users of the devices.
Her research led to four design features that, when combined, help hold people on gambling devices.. Crucially. she found that these features can trigger a trance-like or dissociative state—often described as a “machine zone” or “dark flow”—in which users lose their sense of time and surroundings.. That psychological shift is part of why the experience can become unusually difficult to interrupt. even when a user wants to stop.
What surprised Schüll was how quickly similar features began to show up outside casinos.. Around the early 2010s, the same elements appeared in phone and tablet applications, spanning social media, games, and video-streaming platforms.. In her view. these are not casual products for children in the way a toy or simple object might be; instead. they can create a relationship that keeps young users returning.
Solitude is one of the central ingredients.. When the interaction is primarily between the user and the device. social cues that often help people notice they should stop can disappear.. Schüll explains that it becomes harder to recognize when an activity no longer serves the person—whether they are playing. scrolling. or continuing by habit.. Research cited in the report also points to children who regularly use screens alone in their bedrooms as facing a higher risk of what psychologists describe as problematic usage.. In these patterns. children may keep using an app or game even when it harms their health—such as when it interferes with sleep or friendships—yet they still feel compelled to stay.
Another factor is “bottomlessness,” a design that removes any clear sense of an ending.. In the case of video platforms. new content keeps arriving—new clips on TikTok or YouTube. new photos. comments. and likes on Instagram—while apps can continue feeding material automatically.. Schüll describes the problem as the absence of a natural stopping point. which undermines the feeling of being finished or satisfied.. The result is a persistent “one more” impulse, intensified when the remaining features are present together.
Speed makes that persistence even stronger.. Schüll’s review of research conducted by the gambling industry found that the faster people play video slots. the longer they gamble.. She said speed has a similar effect in app environments: when scrolling. watching. and watching again become rapid. pulling away can become more difficult for many users.. The report quotes Schüll describing how rapid feedback can blur the boundary between the person and the machine. producing a sense of merging—where it becomes unclear where the user begins and the device ends.
In social media and video streaming, that speed has been amplified by technological changes.. The report links the experience of faster content discovery to developments such as higher-speed internet and “infinite scroll. ” both of which help maintain momentum by reducing friction and keeping new material continually available.
The final ingredient is teasing—giving users something close to what they want without delivering it outright.. In the report, Jonathan D.. Morrow. a neuroscientist and psychiatrist at the University of Michigan. ties this to how apps select and schedule content for individuals.. The typical process. as described. involves software using AI to infer what a user hopes to find or see. even if the user does not consciously know what they are seeking.. But rather than providing the complete reward immediately. the app withholds it. offering something nearby first and then another close approximation shortly after.
Morrow argues that apps rarely, if ever, give users exactly what they are looking for.. Instead. they provide “just enough” to keep attention locked in—encouraging ongoing checking and interaction long after the original purpose has faded.. That approach, as framed in the report, creates the belief that the desired payoff is always within reach.. The consequence is that users may remain engaged for long periods. repeatedly hoping the next interaction will finally deliver the “next big thing.”
Taken together. Schüll says these four features—solitude. bottomlessness. speed. and teasing—form a kind of recipe for overuse for nearly everyone.. She has used the design list in teaching settings. including giving students at New York University a framework to evaluate how harmful a given website or app may be by rating it against these criteria.
The report stresses that this combination can be especially harmful for children.. Schüll characterizes the setup as “cruel,” emphasizing that young users are more vulnerable.. In her view. the issue is not simply that children need to practice self-control; rather. she and Morrow agree that children require help regulating their usage and—just as importantly—protection from harmful design.
For educators and families. the implications are less about whether apps are entertaining and more about how their mechanics shape attention.. When features like endless feeds. rapid reward cycles. and personalized teasing combine with reduced social friction. users may struggle to monitor their own engagement.. The warning in this research is that the same “flow” mechanics that keep people playing can shift from harmless amusement to patterns of overuse—particularly when the user is still developing the skills needed to set boundaries.
The broader lesson also extends beyond individual choices.. Because these design elements are engineered into the experience—through automated content. algorithmic selection. and feedback timing—reducing harm may require both guidance and safeguards.. The report ultimately points to a shared responsibility: children need support to manage screen time. and platform design should not be treated as neutral when it can systematically encourage prolonged engagement.
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