Frequent short-video viewers show altered brain function

Young adults who used short-video platforms for at least an hour daily showed stronger communication across numerous brain systems than those reporting less than an hour of use, according to a study published in Frontiers in Human Neuroscience.

Platforms such as TikTok present a rapid stream of brief, attention-grabbing videos, often selected by personalized recommendation systems. Greater use has previously been associated with anxiety, depression, loneliness, and problematic use, but an association does not necessarily mean that the platforms cause these difficulties.

Previous brain-imaging studies have generally scanned people while they watched short videos. These experiments suggest personalized content can engage brain systems involved in attention, self-related thought, and cognitive control. The researchers behind the new study instead examined participants at rest to investigate whether differences were detectable when no videos were being watched.

Siwei He of Chongqing Shapingba Mental Health Center and colleagues recruited 62 healthy adults from China. Seven were excluded because of poor-quality imaging data, leaving 55 participants (average age 21.6 years, including 39 women).

Participants reported their average daily short-video use. Twenty who used the platforms for less than one hour formed the “lower-use” group. The “higher-use” group included 35 participants: 24 reported one to two hours daily and 11 reported two to three hours. Nobody reported more than three hours.

The researchers emphasized that the one-hour division did not represent addiction or pathological use. It simply distinguished comparatively lower and higher use within their sample.

While participants rested in a scanner, functional magnetic resonance imaging (fMRI) measured fluctuations in blood flow associated with brain activity. The researchers examined activity in individual regions, communication within and between brain networks, and the overall organization of connections across the brain.

Higher-use participants showed stronger communication across many connections involving systems responsible for movement, bodily sensations, vision, hearing, attention, cognitive control, and internally directed thought. Particularly robust differences involved sensorimotor, auditory, subcortical, and cingulo-opercular networks. In simple terms, regions involved in processing sensations and movement, detecting sound, relaying information, and maintaining control appeared more tightly coordinated.

Regional activity also differed. The higher-use group showed greater spontaneous activity in the left precentral gyrus, which contributes to movement and sensorimotor processing, but lower activity in part of the right inferior frontal gyrus, a region involved in functions including behavioral control.

At the whole-brain level, higher-use participants had greater global and local efficiency, greater clustering of neighboring regions, and shorter communication paths across the brain. One interpretation for this is that intensive exposure to fast-paced audiovisual material changes brain systems involved in sensory processing and attention. The authors also acknowledged that greater efficiency is not automatically evidence of damage: similar patterns have sometimes been connected with intelligence and working-memory performance.

The researchers could not determine whether this more efficient-looking brain organization was beneficial or harmful because they did not assess attention, memory, or other cognitive abilities. As the authors wrote, “Future studies should incorporate such measures to determine whether the altered brain network topology associated with a relatively higher [short video platform] usage confers cognitive benefits or represents a risk factor for maladaptive outcomes.”

Some limitations are to be noted. For instance, other unmeasured factors—including recent platform use, caffeine, nicotine, and scanning time—could also have influenced brain activity.

The study, “Association between usage intensity of short video platforms and altered brain function: a resting-state functional magnetic resonance imaging study,” was authored by Siwei He, Shixiong Tang, Dayi Liu, Zhiyuan Chen, Qinyu Zou, and Yicheng Long.