www.lesswrong.com/posts/sbcmACvB6DqYXYidL/counter-theses-on-sleep
1 correction found
70% of 84 hunter-gatherers studied in 2013 slept less than 7 hours per day, with 46% sleeping less than 6 hours.
The cited preindustrial-sleep study did not involve 84 people studied only in 2013. The researchers reported sleep records from 94 adults, and the supplemental table shows data collection dates spanning 2013–2015.
Full reasoning
This line misstates the study it refers to.
The UCLA summary of the study says the researchers “collected sleep records on 94 adults for a total of 1,165 days,” not 84 adults. The study also covered three populations: the Hadza of Tanzania, the San of Namibia, and the Tsimane of Bolivia.
The paper’s supplemental material is even more explicit: “Overall there were 47 female and 47 male participants” — i.e. 94 participants total. The same supplement also shows recording dates across multiple years, including Hadza recordings in May 2013, Tsimane recordings in 2013, and San recordings extending into 2014–2015. So the cohort was not simply “84 hunter-gatherers studied in 2013.”
Because the sample-size and timing are both misstated, readers should not take this sentence as an accurate description of the underlying study. At minimum, it understates the study size and incorrectly implies all the data came from 2013.
2 sources
- Our ancestors probably didn't get 8 hours a night, either | UCLA
The team ... collected sleep records on 94 adults for a total of 1,165 days.
- Natural Sleep and Its Seasonal Variations in Three Pre-industrial Societies (supplemental PDF)
Overall there were 47 female and 47 male participants. ... The Hadza were recorded from May 13-20, 2013 ... [and Table S2 lists additional recordings in 2013, 2014, and 2015].