For many of us, the day often starts with a swipe. Before even getting out of bed, we might be scrolling through TikTok, Instagram Reels or YouTube shorts. A few clips become a few dozen. Minutes become an hour. Then, later in the day, we return for more.
Researchers at the University of Bayreuth, Germany, investigated this phenomenon, particularly in children and adolescents.
The review, published in the European Journal of Child and Adolescent Psychiatry, analyzed 42 studies involving nearly 30,000 participants, the majority of whom were adolescents and young adults.
Importantly, the authors examined what is often overlooked in the public debate: the mechanics of the platforms themselves.
Away from TV, on the small screen
The researchers identified three characteristics common to short-form video platforms: the personalization of algorithms, the unpredictability of infinite scroll, and the novelty of rapidly switching between videos.
He says these features create a media environment unlike television, traditional online video or older social networks.
Short-form video platforms work differently. Algorithms continuously select content, users rarely need to make a decision and there is effectively no natural stopping point.
“TikTok is fundamentally different from television,” Aza Raskin, co-founder of the Center for Humane Technology, told DW. “On the other side of the TikTok screen is a giant supercomputer pointed directly at your brain. It’s been trained on the behavior of 3 billion other human primates.”
“The attention economy is essentially a race to the bottom of the brain,” Raskin said. “If TikTok doesn’t take up your time, Facebook, Instagram or any other platform will take up your time.”
“This leads to a brutal stabbing to get the human’s attention,” he said.
Hit and miss of dopamine
Scientists have long understood that highly rewarding experiences activate the brain’s reward system. Short-form videos (SFVs) are particularly effective at taking advantage of that system.
Anna Lembke, associate professor of psychiatry at Stanford University School of Medicine and author of the book dopamine nationtold DW that SFVs include several features that make them unusually attractive.
“Moving images themselves are like the cat to the mammalian brain,” he said. “Short-form videos are a more powerful form, and therefore more addictive, leading to video chaining, which is similar to chain-smoking in that once we start it is difficult to stop, even if we want to.”
Overstimulating the brain’s reward system with highly rewarding unnatural triggers like gambling and overeating causes a flood of the brain’s reward and pleasure neurotransmitter dopamine. To protect itself, the brain becomes “dysregulated” with cells reducing the number of dopamine receptors needed to experience pleasure. Repeated overstimulation can, over time, make the brain less sensitive to reward.
“We need more videos over time, not about getting drunk, but about feeling normal,” he said. “And we lose the ability to engage with others and take pleasure in them, more modest rewards, like watching a sunset, sharing a meal with friends, or reading a good book.”
According to Lembke, the endless nature of modern feeds may gradually change how the reward system responds: “Endless scrolling leads to reward desensitization, that is, less dopamine is released over time in response to similar rewards, requiring more videos with more extreme content to achieve the same effect.”
The result may be a paradox familiar to many users: continuing to search for the next rewarding clip, even when the experience itself is no longer particularly enjoyable.
Why might personalization be most important?
While infinite scrolling gets more of people’s attention, Ben Rein, a neuroscientist, science communicator and author of the book Why does the brain need friends?Believes that the real power lies in attracting the individual.
“Infinite scrolling and novelty matter, but they’re the delivery mechanism; personalization is the engine,” Rein told DW.
He describes a typical TikTok feed as, “a system that runs thousands of little experiments on you, learning faster than you can just watch.”
Rein also argues that personalization becomes especially powerful when it is combined with unpredictability, describing Lembke: “It’s this combination, along with personalization that is part of what makes it so attractive and scalable to every human being who uses social media.”
Lembke sees a similar dynamic. “Through our interactions with the platform the algorithm develops the right drug of choice for each unique individual in real time, which makes the exchange feel organic and alive,” he said.
He said, “Novelty overcomes the boredom that develops with tolerance: that is, requiring more powerful versions over time to achieve the same effect.” “Unpredictability engages the treasure-seeking, questing part of our brain that has evolved to keep us persistent and striving in a harsh ecosystem of rare and uncertain rewards, making those rare rewards all the more rewarding when we find them.”
what comes next?
In the 42 studies examined by the team from the University of Bayreuth, several themes emerged repeatedly.
They include patterns such as high attention difficulties, low working-memory performance, high anxiety and depression, weak self-regulation, and addiction. However, the research team emphasizes that the evidence is limited.
“There is still not enough evidence to claim that short-form video platforms cause ‘brain rot’ or excessive dopamine effects,” lead author Marlene Ebster told DW.
Rather than recommending a complete ban, the authors suggest helping youth understand how recommendation systems work and how platform designs influence behavior.
For Rein, the next frontier for platform designers is likely deep personalization.
“As recommendation models improve, and as AI can tailor or tailor content to the individual in real time, the gap between ‘what you will enjoy’ and ‘what is shown to you’ will continue to diminish.”
The increasing sophistication of artificial intelligence may also become increasingly important.
“We are nowhere near the pinnacle of attention engineering,” Raskin said. “We are now entering the era of AI 2.0, which is generative AI. This technology can actually create completely new content from scratch.”
He warned, “The capabilities of generic AI, from maximizing attention to synthetic media to highly personalized synthetic relationships, will completely dwarf the power of any psychological engineering seen to date.”
Edited by Ben Knight