Watching Reels for Hours? Here’s How Short Videos May Affect Your Brain

Watching Reels on Repeat? Here’s What Short Videos May Be Doing to Your Brain

You open Instagram for a quick break. One Reel turns into another, then another — and before you know it, 30 minutes have disappeared.

That endless-scroll experience is common with short-form content such as Instagram Reels and YouTube Shorts. The rapid stream of new videos keeps attention engaged, but researchers are now examining what happens inside the brain while people watch.

A recent study suggests that short videos may temporarily alter activity in brain regions responsible for cognitive control, particularly when viewers are highly engaged with the content.

What did researchers find?

Published in NeuroImage, the study involved 56 young adults. Researchers used functional magnetic resonance imaging (fMRI) to observe brain activity while participants watched short videos.

They also used proton magnetic resonance spectroscopy to measure levels of neurotransmitters such as glutamate and GABA.

The researchers focused on two areas of the brain’s cognitive-control network: the dorsal anterior cingulate cortex (dACC) and dorsolateral prefrontal cortex (dlPFC).

These regions are involved in several important functions, including maintaining attention, regulating behaviour, making decisions and responding to changes.

Participants watched a range of short clips featuring people, pets, games and nature. Most videos lasted around 30 seconds, and participants were free to skip clips whenever they wanted.

What happened when viewers liked a video?

Researchers compared brain activity when participants continued watching videos they enjoyed with activity when they chose to stop watching.

The results showed lower activity in parts of the cognitive-control network when participants were particularly engaged with a video.

That does not mean the brain stopped working. Rather, specific regions associated with cognitive control showed reduced activity while participants were absorbed in preferred content.

Does watching Reels cause brain damage?

The study does not establish that.

It does not show that Reels permanently damage the brain, nor does it prove that short-form videos cause long-term problems with attention, memory or decision-making.

The research observed changes in brain activity during the viewing experience. It involved only 56 young adults, so the findings should not be treated as proof of how short-form video affects everyone or as evidence of permanent cognitive changes.

The memory question

Researchers are also studying another feature of short-form videos: rapid context switching.

A 2025 study by Nicholas Barton and Michael Smyth, titled Context-switching in short-form videos: What is the impact on prospective memory?, examined whether frequently switching between rapidly changing video contexts could affect prospective memory — the ability to remember something you intend to do in the future.

The findings add to growing scientific interest in how short-form video consumption interacts with attention and memory.

However, the broader research is still evolving. For now, the strongest takeaway is not that Reels are “turning off” your brain, but that the way short-form content captures and holds attention is an area researchers are continuing to investigate.

If scrolling starts eating into your sleep, work, studies or everyday responsibilities, that may be a more practical warning sign than any single brain scan.