GoKawiilMillions of people finish short video after short video every day; a new brain-scan study shows that the very act of finishing a clip they like temporarily quiets the brain regions that normally help them stay focused and weigh longer-term goals. When people watch a short video they enjoy enough to finish, two brain regions involved in cognitive control show significant deactivation. That is the central finding of a new study from Zhejiang University, published in NeuroImagein January 2026. Using functional MRI alongside proton magnetic resonance spectroscopy (¹H-MRS), the research team examined 56 young adults while they freely watched short video clips inside an MRI scanner. Both the dorsal anterior cingulate cortex (dACC) and the dorsolateral prefrontal cortex (dlPFC) showed reduced activity specifically when participants watched clips they liked enough to view to completion.
Cognitive control helps people balance immediate pleasures against longer-term goals, and impairments in this system are linked to conditions such as depression, anxiety, ADHD, and addiction. Short-video platforms present rapid, algorithmically curated streams that are built for continuous, low-effort consumption. Prior behavioral research has tied both internet addiction and smartphone addiction to weaker self-control, and separate neuroimaging work has documented disruptions to reward and cognitive-control circuits in people with behavioral addictions. Despite this, few studies had directly tested whether the act of watching entertaining short videos itself suppresses the brain’s cognitive control regions. The Zhejiang University team set out to answer that question, along with a second one: what neurochemical factors might explain why this suppression varies from person to person?
The dACC and dlPFC form the core of the brain’s cognitive control network. The dACC contributes to conflict monitoring, reward-based decisions, and effort evaluation, and it typically activates during demanding tasks such as the Stroop or Go/No-Go test. The dlPFC, which connects structurally to the dACC, carries out top-down control once the dACC has flagged a need for it. Earlier work from the same lab had already shown that passively viewing personalized short videos suppresses the dACC, regardless of whether the content was algorithmically recommended or generic. Separately, prior neurochemical research has linked resting-state glutamate concentrations in the anterior cingulate cortex to stronger task-related brain activation, while GABA concentrations have been associated with reduced activation in some contexts. However, these metabolite-to-activity relationships have proven inconsistent across different types of cognitive tasks.
The team recruited 66 volunteers and excluded 10 for excessive head motion or low-quality spectroscopy data, leaving a final sample of 56 participants (37 men and 19 women, average age 23.3). All participants reported some existing experience with short-video apps. Before scanning, the researchers measured resting-state glutamate and GABA concentrations in each participant’s dACC using a MEGA-PRESS spectroscopy sequence, with a matched voxel in the visual cortex serving as a control region.
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During the scan, participants watched two six-minute blocks of short clips drawn from a library of 160 videos spanning five categories: single-person actions, multi-person interactions, pets, game scenes, and natural scenery. Average clip length was 23.7 seconds. Participants could press a button at any time to skip to the next clip. Based on viewing behavior, each video was classified as “liked” (watched to the end), “disliked” (skipped before the halfway point), or a third category for clips skipped after the halfway point. On average, participants watched about 19 liked videos and 36 disliked videos per session. The study had been preregistered in September 2024, and the analysis plan set a Bonferroni-corrected significance threshold to account for multiple comparisons.
Both the dACC and dlPFC deactivated significantly below baseline while participants watched liked videos. During disliked videos, the pattern diverged: dACC activity stayed close to baseline, while dlPFC activity remained suppressed, though less severely than during liked viewing. Directly comparing conditions confirmed that both regions showed significantly greater suppression during liked video viewing than during disliked viewing. The visual cortex, used as a control region, activated during both video types with no difference between them, indicating the deactivation pattern was specific to cognitive control regions rather than a general effect of watching video.
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Regional Brain Activation During Liked vs. Disliked Video Viewing Bar height is proportional to the t(55) statistic reported in the paper. Bars below the center line indicate significant deactivation; bars above indicate significant activation. ADVERTISEMENT t=-6.30*** liked t=-0.90, n.s. disliked dACC t=-12.20*** liked t=-3.73*** disliked dlPFC t=5.21*** liked t=7.76*** disliked V1 (control) Significant deactivation Significant activation Not significant vs. baseline ***p<.001
Resting-state dACC glutamate concentration also mattered. Independent of GABA, higher dACC glutamate predicted less suppression of dACC activity during both liked and disliked viewing, and less suppression of dlPFC activity during disliked viewing. The link between glutamate and dlPFC activity during liked viewing did not reach statistical significance. GABA concentration, meanwhile, correlated significantly with activation in the visual-cortex control region but showed no significant relationship with dACC or dlPFC activity.
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