Watching your favorite short videos can temporarily quiet areas of the brain involved in self-control and monitoring, and this effect may be linked to levels of the brain chemical glutamate. This study neuroimage.
Short video platforms are built around quick and engaging clips that users can continue or skip within seconds. While these platforms may be entertaining and harmless for many people, researchers are becoming increasingly interested in why some users find it difficult to stop using them. One possible explanation is that immersive and enjoyable viewing may reduce the need for active monitoring and self-control.
The new study focused on two brain regions: the dorsal anterior cingulate cortex and the dorsolateral prefrontal cortex. The dorsal anterior cingulate cortex helps detect conflict, monitor behavior, and determine when more mental effort is needed. The dorsolateral prefrontal cortex is involved in applying control, such as maintaining focus and resisting distraction. Together, these areas help people regulate their behavior in situations that require caution and restraint.
The researchers also looked at two brain chemicals. Glutamate is the brain’s main excitatory neurotransmitter and helps increase nerve activity. Gamma-aminobutyric acid (GABA) is the brain’s main inhibitory neurotransmitter and helps reduce or modulate neural activity. The researchers wanted to know whether these chemicals, measured at rest, could help explain why people differ in how strongly their cognitive control networks respond during short video viewing.
Researchers led by Tiantian Hong from Zhejiang University in China recruited 66 young people. After excluding participants due to excessive head movements or poor quality brain chemistry scans, the final sample included 56 people with an average age of approximately 23 years. The sample included 19 women.
Participants first underwent proton magnetic resonance spectroscopy, a brain imaging technique used to estimate glutamate and GABA concentrations in the dorsal anterior cingulate cortex. They then completed a task of watching a short video during functional magnetic resonance imaging, which measures changes in brain activity. Participants watched two 6-minute videos and could press a button to skip to the next video at any time. Videos that are watched to the end are treated as “likes”, and videos that are skipped halfway are treated as “dislikes”.
The main finding was that liked videos were associated with significant deactivation of both cognitive control regions. In other words, when participants watched videos that they allowed to continue, activity in the dorsal anterior cingulate cortex and dorsolateral prefrontal cortex decreased below baseline.
Disliked videos showed a different pattern. During these videos, activity in the dorsal anterior cingulate cortex was not significantly different from baseline, but the dorsolateral prefrontal cortex was still suppressed. The visual cortex, which processes visual information, was active in both liked and disliked videos, suggesting that this result was not simply due to participants looking at a screen.
Hong et al. also found that people with higher resting glutamate levels in the dorsal anterior cingulate cortex had less inhibition of both cognitive control regions during video viewing. GABA was not significantly associated with activity in these regions. The authors concluded that immersive viewing of preferred short videos deactivated cognitive control networks and that individual differences in this deactivation were related to glutamate metabolism.
Interestingly, connectivity between the dorsal anterior cingulate cortex and the dorsolateral prefrontal cortex increased during viewing of short videos, especially videos that were liked. The authors caution that this does not necessarily mean increased self-control. Instead, they suggest that the two regions may be downregulated together during priority viewing, producing a more coordinated pattern of decreased activity.
Please note some limitations. For example, short video addiction or compulsive use was not assessed in detail in this study, and videos that were “liked” were defined by whether participants continued to watch them, rather than by explicit ratings after viewing. Furthermore, this study only included young people who wore primarily male makeup, which limits the generalizability of the results.
The study, “Brain Activity Inhibition During Short Video Viewing: Neurochemical Insights,” was authored by Tiantian Hon, Conghui Su, Hui Zhou, Fengji Geng, and Yuzheng Hu.
