Apparently, the average human body temperature has been decreasing since the beginning of the Industrial Revolution, when Carl Wunderlich’s records established 37 C (98.6 F) as the norm. In the U.S., it’s declined by 0.03 C per decade, and is now as low as 36.4 C (97.5 F).

The theory has been that increasing access to modern vaccines, antibiotics, and clean drinking water has decreased the body’s background inflammatory response—but it wasn’t proven. This study out of U.C.-Santa Barbara does that, using health data from a group of farmer-gatherers in the Bolivian Amazon, who have been undergoing rapid changes in their access to healthcare over the last two decades because of new social programs in Bolivia. The team found that, indeed, the average body temperature of the Tsimane began at 37.0 C and has decreased by a full degree after these government interventions.

This is all new to me, and made me think about how everything is economics. There’s an energy cost to maintaining a higher basal temperature, and being able to use that energy elsewhere is a bio-economic transaction. And where is that extra capital we’re given by modern medicine spent? Could this be why other studies show that general intelligence has been increasing over the last two centuries, as well? Or do we just store it for the future as fat, which is also increasing?

And then the fact that we’re becoming more cold-blooded as a consequence of that bio-economics reminded me of the studies suggesting that wealth decreases empathy—a psycho-economic transaction, where decreased vulnerability leads to a decrease in reciprocal altruistic reward. The famous study shows that more expensive cars are less likely to stop for pedestrians at a crosswalk.

So everything is economics, on every level, including the prosperous but cold math of the global economy expanding its reach into the Amazon. As always, it was fun trying to cram all of these thoughts into a tiny Sunday sciku.

 

economics—
we find it healthy to grow
cold-blooded

 

For a long time I’ve been interested the Snake Detection Hypothesis, which says that it was primates’ co-evolution with snakes that allowed for the rapid development of our excellent vision—we had to be able to quickly recognize camouflaged snakes so they wouldn’t kill us as we coexisted for millions of years in the same habitat. My hunch has been, though I’ve never found any research on this topic, that it’s this same high-contrast pattern detection that allows us to read text, and that the “visual word form area” of the brain is an adaptive overlay on top of the snake detection area. If you look at the pattern on a snake, it kind of looks like text. Which has cool implications for the Eden myth, where it was the snake that taught us knowledge. I have no idea whether or not this is true, but it would be interesting if it is.

Anyway, this paper points toward that hypothesis, showing that the visual word form area is pre-wired into the brains of infants. They put 40 newborns into an fMRI machine and showed that they already have the VWFA. Which begs the question—how could this module have already evolved when majority literacy (let alone universal literacy) is only 75 years old? In 1820, only 12% of the global population could read—yet we already have a pre-wired VWFA just 200 years later? How is that possible? My answer: snakes.

 

your first words
snaking across the page
parting the grass

 

A lot of the cool things about this story are in the science paper but not the article: They found mile-long tracks at White Sands National Park and determined it was a girl carrying a toddler, shifting the kid from one hip to the other and occasionally putting it down. She walked in a straight line like she knew exactly where she was going, at about 3.8 mph, so a brisk pace, and then followed the same path back a few hours later without the toddler. During the time in between, a giant ground sloth and a mammoth crossed her tracks. The mammoth just kept walking, but the ground sloth sniffed, then stood on its hind legs to look around, seemingly worried about human predation. A whole mysterious story in these tracks—and what happened to the toddler?

 

such a long walk into the future fossil