A Lab Timed 56 Students Watching TikTok. On Average, They Guessed Long, Not Short.

Twenty eight college students in Suzhou, China, sat down for a psychology experiment that sounds almost too simple to publish. Researchers handed them a phone, told them to watch five minutes and twenty three seconds of short videos, and asked one question when the clip ended: how long do you think that just took?

The guesses ran long, not short. On average, participants in the 2025 study from Soochow University and Anhui Normal University put the task at about 21 percent longer than its actual length, a statistically significant overshoot that runs opposite the usual complaint about short form video, that it erases time without anyone noticing.

That finding sits awkwardly next to a story The Wall Street Journal published this week, headlined 'Teens Who Can't Put Down TikTok and Instagram Are Losing Their Sense of Time.' The Journal's reporting draws on a different, larger body of research and quotes Dr. Vera Feuer, chief clinical officer at the Child Mind Institute, on why teenagers struggle more than adults with exactly this kind of trade off.

“We know young people have difficulty with patience, tolerating frustration and delaying gratification.”

Feuer's point centers on the prefrontal cortex, the brain region that handles planning and impulse control and does not finish developing until the mid twenties. Teenagers are working with less of that machinery than the college students in the lab study, which is part of why some researchers have stopped asking how long five minutes feels and started asking a bigger question instead.

The real finding might not be about the clock at all

A separate, far larger study published this year in Computers in Human Behavior followed 1,567 first year high school students in eastern China for a full year, surveying them three times, six months apart. The team, led by Guanxing Xiong at South China Normal University, was not measuring how long five minutes felt. It was tracking something called future time perspective, a person's ability to connect what they do right now to where it leads later.

Students with heavier short video habits lost ground on that measure over the course of the year, and the drop mattered beyond the videos themselves. Future time perspective predicted academic buoyancy, the researchers' term for a student's ability to shake off a bad test grade or a confusing lesson and keep going. Lose the sense that today connects to some later point, and an ordinary school setback starts to feel bigger than it is.

Neither study is the last word. The time distortion experiment ran on 56 college students in a single sitting, not teenagers living their daily lives, and the authors noted participants could potentially glance at their own phone's clock mid task. The year long study is correlational by design. It cannot prove short video use causes the drop in future thinking rather than following from it, and its authors flagged that a competitive Chinese high school system may not generalize to classrooms elsewhere.

What is already changing because of research like this

Policy is not waiting for a replication. In August, Meta agreed to pay up to 18 billion dollars to settle claims from 47 states over how Instagram and Facebook affected young users, one of the largest consumer settlements of the year, according to PBS NewsHour's coverage of the deal.

• A default two hour daily limit across Instagram and Facebook that teens cannot turn off without a parent's permission
• A new night mode blocking Feed, Stories, Explore, and Reels between midnight and 6 a.m., though direct messages still work
• No push notifications during weekday school hours
• New limits on social comparison features such as visible like counts

The limits target exactly the platform most implicated in this kind of research. TikTok is the single most time intensive app for American teenagers, averaging one hour and eighteen minutes a day, and about one in five of the 1,458 teens Pew Research Center surveyed in late 2025 said they are on TikTok almost constantly. Instagram and Snapchat each drew a lighter 12 percent 'almost constant' figure in the same survey.

The two studies answering the same broad worry are not actually testing the same thing. Whether a five minute clip feels like five minutes or six and a half is a small, mixed result from one lab test. Whether a teenager still believes today connects to next year is the larger, better supported question, and it is also the one Meta's own court appointed auditor will be checking against, wave by wave, for the next decade.