Does firelight influence sleep quality?

I tweeted yesterday to David Samson that Asher Rosinger is making me look bad, so all the collaborations that make him so productive. Of course, I'm not really competing with Asher. We just profiled Asher's productivity on a recent Sausage of Science podcast for the Human Biology Association, but it is motivating.

https://twitter.com/Chris_Ly/status/1048337483220627456

David and I spoke in 2016 about collaborating on a study of sleep and fire. Truth is, both of these guys have been very productive, and David has already taken the first step in this research direction already. In a paper that came out last year (Hadza sleep biology: evidence for flexible sleep-wake patterns in hunter-gatherers. American Journal of Physical Anthropology), David and his colleagues examined sleep patterns among the Hadza with regard to fire and other factors. They did not find an influence of campfires on sleep patterns, but they make a thoughtful suggestion for our future research. How does fire influence waking cognition? We know smartphones, televisions, and the associated blue light has influences on attention and such. It's time to delve into the light that influenced our brains for most of the last 400,000 years.

A functional linear modeling comparison between the 24-hr sleep-wake pattern of the Hadza and a small scale agricultural society in Madagascar characterized as nocturnally bi-phasic, segmented sleepers. The Madagascar population showed a pronounced increased activity after midnight and a pronounced decrease in activity around noon, whereas the Hadza showed continually increased activity from sleep’s end until noon when activity showed a steady decrease until a prolonged consolidated bout of sleep in early morning. The bottom panel illustrates the point-wise critical value (dotted line) is the proportion of all permutation F values at each time point at the significance level of 0.05. When the observed F-statistic (solid line) is above the dotted line, it is concluded the two groups have significantly different mean circadian activity patterns at those time points [Color figure can be viewed at wileyonlinelibrary.com][/caption]