Short-form video viewing temporarily quiets brain’s cognitive control regions, study finds
A new study from Zhejiang University suggests that watching TikTok and Instagram Reels shifts the brain toward low-effort processing rather than impairing cognitive function.
A study conducted by Zhejiang University and published in the journal NeuroImage has found that watching short-form videos on platforms such as TikTok and Instagram Reels temporarily deactivates key brain regions associated with cognitive control. The research, which utilised functional MRI and proton magnetic resonance spectroscopy, examined how the brain responds to the rapid, algorithmically curated streams that define modern short-video consumption.
The research team analysed data from 56 young adults, comprising 37 men and 19 women with an average age of 23.3 years. Participants viewed two six-minute blocks of short clips, with an average length of 23.7 seconds, drawn from categories including pets, game scenes, and natural scenery. Researchers classified the videos based on viewing behaviour, distinguishing between clips watched to completion and those skipped before the halfway point.
The findings revealed that both the dorsal anterior cingulate cortex and the dorsolateral prefrontal cortex showed significantly reduced activity when participants watched clips they liked enough to view to the end. These regions form the core of the brain’s cognitive control network, which typically helps individuals balance immediate pleasures against longer-term goals. The deactivation was specific to these cognitive areas, as the visual cortex, used as a control region, activated normally during both liked and disliked video viewing.
The study also explored neurochemical factors, measuring resting-state glutamate and GABA concentrations in the participants. Higher levels of glutamate in the dorsal anterior cingulate cortex were associated with less suppression of activity in both the dorsal anterior cingulate cortex and the dorsolateral prefrontal cortex during video viewing. This suggests that individual neurochemical profiles may influence how the brain adapts to passive media consumption.
The authors caution against interpreting this deactivation as a failure of cognitive capacity. Instead, they argue the pattern likely reflects an adaptive shift toward low-effort, automatic processing during passive viewing. They note that participants remained actively engaged, skipping disliked clips on roughly 57 per cent of trials, which points to sustained evaluation rather than disengagement or mind-wandering.
The study, which was preregistered in September 2024, acknowledges several limitations, including the lack of a validated addiction scale to assess habitual use and the correlational nature of the neurochemical findings. The sample consisted of young, healthy adults, meaning the results may not generalise to other age groups or populations with different metabolic profiles.
