What happened
- A longitudinal study published in Current Biology on October 15, 2026, and covered by Nature on October 23, followed sleep in Toba/Qom communities in northern Argentina between 2012 and 2024.
- It included rural groups that got electricity after 2016 and semi-urban groups that already had it. Researchers recorded more than 12,000 sleep episodes from 156 participants with actigraphs, wrist-worn sensors.
- Both groups delayed their sleep timing by close to an hour. Participants from rural communities lost 35 minutes of sleep over a decade.
Why it matters
- It is often assumed that artificial light and digital technology delay and shorten sleep, but direct longitudinal evidence is scarce. This study measured the change as it happened.
- The period included first the arrival of electricity and, in recent years, the spread of the internet and smartphones.
- According to the authors, those two factors alone do not explain the delay in timing, which points to broader processes of modernisation and acculturation.
The number
35 minutes. Sleep per night lost by participants from rural communities over a decade of follow-up.
Context
The team is from Universidad de San Andrés and Conicet in Argentina, with the University of Washington. The authors include Leandro Casiraghi, Diego Golombek and Horacio de la Iglesia. The authors present the case as a present-day parallel of the sleep changes believed to have come with industrialisation. Circadian rhythms are linked to mental health in other work, such as the circadian subtype of depression found in Sydney, and technology use to wellbeing in the year-long study of AI companions.
What’s next
- The results serve as a reference for communities just starting to use electricity and the internet.
- It remains to separate how much of the change comes from light, screens and other changes in daily life.
Bottom line
A decade was enough for sleep in these communities to look more like a city’s. The biological history of the Americas is also rebuilt from collections, such as museum DNA that places the origin of barn owls in the Caribbean. And behaviour that changes after an experience is observed in macaques that avoid contaminated food.
Sources
- Current Biology — Longitudinal study of Toba/Qom communities reveals delay and shortening of sleep in real time (October 15, 2026; abstract read on PubMed)
- Nature — Sleep declines in rural communities after electricity arrives (October 23, 2026)
- Cover image: Shixart1985, CC BY 2.0, via Wikimedia Commons
Edited by Rodrigo Cornejo. How we select and verify: who writes these notes.
