Loading lags of just one or two seconds hurt students’ online learning

In two field studies covering more than 80,000 learners, brief loading delays of 1 to 2 seconds predicted fewer completed assignments and lessons, more distraction and multitasking, and lower scores.

Illustration of a student at a laptop with a loading circle on screen, glancing away at a phone
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Loading delays of just one or two seconds can make online learners less engaged and less successful, a new study suggests. Students who ran into these brief lags completed less work, got distracted more often and earned lower scores.

The study, titled “Microdelays disrupt online learning,” was written by Asaf Mazar, Geoff Tomaino, Abubakir Siedahmed, Ahmad Abdolsaheb, Neil T. Heffernan, Ziv Carmon and Angela L. Duckworth. It was published online in Nature Human Behaviour on October 8, 2026.

Small waits, measured at scale

The researchers call these short loading lags microdelays, and point out that they may weigh most on learners with slower internet connections. They tracked them in two longitudinal field studies.

The first followed 26,707 US primary and secondary school students doing online math assignments. When they hit microdelays, they completed fewer assignments, took longer to finish them, were more likely to get distracted mid-task and earned lower scores.

The second followed 55,184 aspiring coders, mostly in Latin America. Those who experienced microdelays spent less time actively engaged, multitasked more, completed fewer lessons and were less likely to reach a key course milestone.

Comparing learners with themselves

The analyses compared each learner’s own experience when load times were faster and slower, which helps rule out the explanation that some learners are simply less motivated than others. The authors say this supports a causal reading, and the results held across a range of model specifications.

The authors conclude that microdelays are a barrier to online learning that has so far been overlooked. The abstract does not give the size of the drops in scores or completion, so how much a single delay costs cannot be judged from it.

Study Details:

  • Title: Microdelays disrupt online learning
  • Authors: Asaf Mazar, Geoff Tomaino, Abubakir Siedahmed, Ahmad Abdolsaheb, Neil T. Heffernan, Ziv Carmon, Angela L. Duckworth
  • Journal: Nature Human Behaviour
  • Publication Date: October 8, 2026 (online)
  • DOI: 10.1038/s41562-026-02598-y