The largest piece of evidence is a 2026 meta-analysis published in Psychological Bulletin, pooling data from 98,299 participants across 71 separate studies. It found that heavier engagement with short-form video, spanning TikTok, Instagram Reels, YouTube Shorts, and Douyin, was associated with poorer cognitive performance, specifically reduced attention span and weaker inhibitory control, the ability to stop yourself from doing something automatic.
Related research describes the everyday experience that data points to. Continuous partial attention, mental fog, and difficulty sustaining focus on complex tasks show up repeatedly in self-reports from heavy short-form users, alongside associations with higher stress and anxiety. A phenomenological study of university students specifically described attention deficits and emotional desensitization tied to prolonged exposure to low-quality digital content.
Researchers have gone as far as building a measurement tool for it. The Brain Rot Scale is a validated 14-item questionnaire covering three factors: attention dysregulation, digital compulsivity, and cognitive dependency, tested across more than 1,300 participants aged 8 to 24. That it exists at all says something: this isn't purely a vibe. Someone built a psychometric instrument to quantify it.