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The strangest finding in the research on studying with screens involves students who did nothing wrong. In a controlled classroom experiment cited in a 2018 literature review in the International Journal of Educational Technology in Higher Education, participants who stayed off their own devices but sat in direct view of a multitasking peer scored 17% lower on a comprehension test than students with an unobstructed view of the lecture. The distraction spread like secondhand smoke.
If a nearby screen costs that much, what does a student's own open tab cost?
68% of students believe they can text through a lecture. Their grades disagree.
The 2018 review, which synthesized 38 studies published between 2003 and 2017, found that media multitasking negatively associated with GPA, test performance, recall, and reading comprehension. The confidence gap runs through the same body of research. One survey in the review found 68% of students believed they could follow a lecture and text at the same time. The students who texted earned lower grades. Another study logged 3,372 self-directed computer sessions and found 99% involved some form of multitasking.
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The cost shows up in time as well as accuracy. In two experiments covered by the review, students who instant messaged while reading took 22% to 59% longer to finish the passage, even after the minutes spent messaging were subtracted. The second screen taxes the work twice.
A 2025 meta-analysis puts the correlation at roughly − 0.25
A meta-analysis published in 2025 in the International Journal of Cognitive Research in Science, Engineering and Education pooled 11 correlational studies on academic media multitasking and achievement. The result: a weighted average correlation of −0.25, a negative relationship the authors describe as low in intensity but consistent across models.
The data is correlational, so it can't prove that scrolling causes lower grades. The content of the second screen also appears to moderate the effect. Research in the 2018 review found students who sent lecture-related texts performed far closer to non-texters than students messaging about anything else, and off-task use accounts for most of the penalty.
A modest penalty still adds up. A small drag applied to every study session compounds across a semester the way a small fee compounds across an investment account.
Timed single-task blocks address the mechanism directly
If divided attention is the mechanism, the practical response is a protected single-task window. That's the logic behind timeboxing methods built for studying. Quizlet's Pomodoro timer, for example, breaks a session into 25-minute timed segments separated by short breaks, which gives the brain one job at a time and a scheduled moment to handle whatever piled up in the interim. Twenty-five minutes is enough, provided the attention inside the block stays whole.
Students predicted the direction of the damage and lowballed the size
The most durable finding in this research concerns self-assessment. In one prediction study covered in the 2018 review, students forecast the direction of multitasking's effect on their homework correctly, then underestimated its magnitude. People know the second screen costs something. They lowball the bill.
That misjudgment is why the review's authors built their recommendations around habit design, suggesting measures like completing schoolwork before opening media at all. For students heading back to campus this fall with more notifications and open tabs than any prior cohort, the advice arrives with a measurable cost attached: a consistent negative correlation across a decade of studies, and a bill most of them are still underestimating.
