Some interesting things

Here’s a post a friend linked me to detailing the writer’s experience of discovering that the true background of two famous photos of the Vietnam War was very different from the background they had been taught:

As I read the article about the photos, I felt a sense of disbelief. I wasn’t quite sure what I was reading was correct. Surely, if this information about both photos were true, I’d have heard about it before this. After all, thirty years had passed.

I spent the next few hours searching the subject online and found quite a bit more information, but no serious or credible refutation of the stories I’d just learned. …

Then the strangest feeling came over me. I don’t even have a word for it, although I usually can come up with words for emotions.

This was a new feeling. The best description I can come up with is that it was a regret so intense it morphed seamlessly into guilt, as though I were responsible for something terrible, though I didn’t know exactly what. Regret and guilt, and also a rage that I’d been so stupid, that I’d let myself be duped or misled or kept ignorant about something so important, and that I’d remained ignorant all these years.

I sat in front of my computer and put my face down on the keyboard. I stayed in that position for a few minutes, energyless and drained. When I lifted my head I was surprised to find a few tears on my cheeks.

This is the emotion more blasely referred to as “red pilling;” the moment you realize that many of the things you had been taught to believe are, in fact, a lie.

It’s a very interesting article and I encourage you to read it.

Denisovan Jawbone in Tibet?

But now, an international team of scientists has announced the identification of another Denisovan fossil, from a site 1,500 miles away. It’s the right half of a jawbone, found some 10,700 feet above sea level in a cave in China’s Xiahe County, on the eastern edge of the Tibetan plateau. The Xiahe mandible, as it is now known, is not only the first Denisovan fossil to be found outside Denisova Cave, but also the very first Denisovan fossil to be found at all. It just took four decades for anyone to realize that.

So there may be a lot of old bits of bone or pieces of skulls lying unidentified in various old collections, especially in Asia, that we’ll be able to identify and piece together into various homo species as we fill in more of the information about our human family tree

To be honest, I am a little annoyed about how every article about the Denisovans expresses a form of supposed confusion at how a group whose only fossils (until now) were found in a cave in Siberia could have DNA in Tibetans and Melanesians. Obviously we just haven’t figured out the full ancestral ranges of these groups, and they used to overlap. If Tibetans have high-altitude adaptations that look like they came from Denisovans, then obviously Denisovans lived in Tibet, and old Tibetan bones are a great place to look for Denisovans.

Indeed, the Xiahe mandible, which is 160,000 years old, is by far the earliest hominin fossil from the Tibetan plateau. Researchers used to think that Homo sapiens was unique in adapting to the Himalayas, but the Denisovans were successfully living on the roof of the world at least 120,000 years earlier. They must also have adapted to extremely thin air—after all, the mandible was found in a cave that’s some 8,000 feet higher above sea level than Denisova itself. “Their presence that high up is truly astonishing,” Douka says.

Fascinating article about the genetics of circadian rhythms and their relationship to health matters:

Perhaps the most ubiquitous and persistent environmental factor present throughout the evolution of modern species is the revolution of the earth about its own axis, creating a 24 h solar day. The consequent recurrent pattern of light and darkness endows a sense of time to organisms that live on this planet. The importance of this sense of time is accentuated by an internal clock that functions on a 24 h scale, inherent in the genetic framework of living organisms ranging from cyanobacteria (Johnson et al., 1996) to human mammals (Herzog and Tosini, 2001). An internal, molecular program drives circadian oscillations within the organism that manifest at the molecular, biochemical, physiological and behavioral levels (Mazzoccoli et al., 2012). Importantly, these oscillations allow anticipatory responses to changes in the environment and promote survival.

The term “circadian” comes from the Latin “circa,” meaning “around” and “diem,” meaning “day.” Circadian events recur during the subjective day or the lighted portion of the 24 h period and the subjective night or the dark part of the 24 h period allowing physiological synchrony with the light/dark environment (Reddy and O’Neill, 2010). The circadian clock has been demonstrated in almost all living organisms (Johnson et al., 1996Herzog and Tosini, 2001Mazzoccoli et al., 2012). The two defining characteristics of the circadian timing system are perseverance of oscillation under constant environmental conditions, which define these rhythms as self-sustained and endogenously generated, and the ability to adapt to environmental change, particularly to changes in the environmental light/dark cycle (Tischkau and Gillette, 2005).

The fascinating thing about sleep is that it exists; you would think that, given how vulnerable we are during sleep, animals that sleep would have long ago been eaten by animals that don’t, and the entire kingdom would have evolved to be constantly awake. And yet it hasn’t, suggesting that whatever sleep does, it is vitally important.

Modern Shamans: Financial Managers, Political Pundits, and others who help tame life’s uncertainties:

Like all magical specialists, [shamans] rely on spells and occult gizmos, but what makes shamans special is that they use trance. …

But these advantages are offset by the ordeals involved. In many societies, a wannabe initiate lacks credibility until he (and it’s usually a he) undergoes a near-death experience or a long bout of asceticism.

One aboriginal Australian shaman told ethnographers that, as a novice, he was killed by an older shaman who then replaced his organs with a new, magical set. …

Manifesting as mediums, channelers, witch doctors and the prophets of religious movements, shamans have appeared in most human societies, including nearly all documented hunter-gatherers. They characterized the religious lives of ancestral humans and are often said to be the “first profession.” …

… Like people everywhere, contemporary Westerners look to experts to achieve the impossible – to heal incurable illnesses, to forecast unknowable futures – and the experts, in turn, compete among themselves, performing to convince people of their special abilities.

So who are these modern shamans?

According to the cognitive scientist Samuel Johnson, financial money managers are likely candidates. Money managers fail to outperform the market – in fact, they even fail to systematically outperform each other – yet customers continue to pay them to divine future stock prices. …

Very interesting insight. It might explain why we stuck with doctors for so many centuries even when they were totally useless (or even negatively useful,) and why we trusted psychiatry throughout most of the 20th century, despite it being obvious bullshit.

There are a lot of unknowns out there, and we feel more comfortable trusting someone than just leaving it unknown–which introduces a lot of room for people to take advantage of us.

Finally, on a similar note, Is Dogma Eugenic? 

As he explains, belief in the supernatural can be attributed to the above heuristics. If belief in the supernatural became a problem, we would have to evolve to loose those heuristics.

Heuristics can be good. But, insofar as heuristics have us create harmful dogmas that can perpetuate themselves socially, we will have to replace them with pure logic, or at least lessen their impact. 

So, insofar as humans have the capacity to believe harmful dogmas, we will lose heuristics and become more logical. Heuristics can be “gamed;” logic cannot. In this manner, humans evolve to act less on instinct. The logical part of our brain becomes more pronounced.

You might have to RTWT to really get the argument, but it’s fun.

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Links Post: Evolution and More

road-to-bigger-brains
From State of the Science: Finding Human Ancestors in New Places

The Puerto Rican rainforest is beautiful and temporarily low on bugs. (Bugs, I suspect, evolve quickly and so can bounce back from these sorts of collapses–but they are collapses.)

More evidence for an extra Neanderthal or Denisovan interbreeding event in East Asians and Melanesian genomes:

 In addition to the reported Neanderthal and Denisovan introgressions, our results support a third introgression in all Asian and Oceanian populations from an archaic population. This population is either related to the Neanderthal-Denisova clade or diverged early from the Denisova lineage.

(Congratulations to the authors, Mondal, Bertranpetit, and Lao.)

Really interesting study on gene-culture co-evolution in Northeast Asia:

Here we report an analysis comparing cultural and genetic data from 13 populations from in and around Northeast Asia spanning 10 different language families/isolates. We construct distance matrices for language (grammar, phonology, lexicon), music (song structure, performance style), and genomes (genome-wide SNPs) and test for correlations among them. … robust correlations emerge between genetic and grammatical distances. Our results suggest that grammatical structure might be one of the strongest cultural indicators of human population history, while also demonstrating differences among cultural and genetic relationships that highlight the complex nature of human cultural and genetic evolution.

I feel like there’s a joke about grammar Nazis in here.

Why do we sleep? No one knows.

While humans average seven hours, other primates range from just under nine hours (blue-eyed black lemurs) to 17 (owl monkeys). Chimps, our closest living evolutionary relatives, average about nine and a half hours. And although humans doze for less time, a greater proportion is rapid eye movement sleep (REM), the deepest phase, when vivid dreams unfold.

Sleep is pretty much universal in the animal kingdom, but different species vary greatly in their habits. Elephants sleep about two hours out of 24; sloths more than 15. Individual humans vary in their sleep needs, but interestingly, different cultures vary greatly in the timing of their sleep, eg, the Spanish siesta. Our modern notion that people “should” sleep in a solid, 7-9 hour chunk (going so far as to “train” children to do it,) is more a result of electricity and industrial work schedules than anything inherent or healthy about human sleep. So if you find yourself stressed out because you keep taking a nap in the afternoon instead of sleeping through the night, take heart: you may be completely normal. (Unless you’re tired because of some illness, of course.)

Interestingly:

Within any culture, people also prefer to rest and rise at different times: In most populations, individuals range from night owls to morning larks in a near bell curve distribution. Where someone falls along this continuum often depends on sex (women tend to rise earlier) and age (young adults tend to be night owls, while children and older adults typically go to bed before the wee hours).

Genes matter, too. Recent studies have identified about a dozen genetic variations that predict sleep habits, some of which are located in genes known to influence circadian rhythms.

While this variation can cause conflict today … it may be the vestige of a crucial adaptation. According to the sentinel hypothesis, staggered sleep evolved to ensure that there was always some portion of a group awake and able to detect threats.

So they gave sleep trackers to some Hadza, who must by now think Westerners are very strange, and found that at any particular period of the night, about 40% of people were awake; over 20 nights, there were “only 18 one-minute periods” when everyone was asleep. That doesn’t prove anything, but it does suggest that it’s perfectly normal for some people to be up in the middle of the night–and maybe even useful.

Important dates in the evolution of human brain genes found:

In May, a pair of papers published by separate teams in the journal Cell focused on the NOTCH family of genes, found in all animals and critical to an embryo’s development: They produce the proteins that tell stem cells what to turn into, such as neurons in the brain. The researchers looked at relatives of the NOTCH2 gene that are present today only in humans.

In a distant ancestor 8 million to 14 million years ago, they found, a copying error resulted in an “extra hunk of DNA,” says David Haussler of the University of California, Santa Cruz, a senior author of one of the new studies.

This non-functioning extra piece of NOTCH2 code is still present in chimps and gorillas, but not in orangutans, which went off on their own evolutionary path 14 million years ago.

About 3 million to 4 million years ago, a few million years after our own lineage split from other apes, a second mutation activated the once non-functional code. This human-specific gene, called NOTCH2NL, began producing proteins involved in turning neural stem cells into cortical neurons. NOTCH2NL pumped up the number of neurons in the neocortex, the seat of advanced cognitive function. Over time, this led to bigger, more powerful brains. …

The researchers also found NOTCH2NL in the ancient genomes of our closest evolutionary kin: the Denisovans and the Neanderthals, who had brain volumes similar to our own.

And finally, Differences in Genes’ Geographic Origins Influence Mitochondrial Function:

“Genomes that evolve in different geographic locations without intermixing can end up being different from each other,” said Kateryna Makova, Pentz Professor of Biology at Penn State and an author of the paper. “… This variation has a lot of advantages; for example, increased variation in immune genes can provide enhanced protection from diseases. However, variation in geographic origin within the genome could also potentially lead to communication issues between genes, for example between mitochondrial and nuclear genes that work together to regulate mitochondrial function.”

Researchers looked at recently (by evolutionary standards) mixed populations like Puerto Ricans and African Americans, comparing the parts of their DNA that interact with mitochondria to the parts that don’t. Since mitochondria hail from your mother, and these populations have different ethnic DNA contributions along maternal and paternal lines. If all of the DNA were equally compatible with their mitochondria, then we’d expect to see equal contributions to the specifically mitochondria-interacting genes. If some ethnic origins interact better with the mitochondria, then we expect to see more of this DNA in these specific places.

The latter is, in fact, what we find. Puerto Ricans hail more from the Taino Indians along their mtDNA, and have relatively more Taino DNA in the genes that affect their mitochondria–indicating that over the years, individuals with more balanced contributions were selected against in Puerto Rico. (“Selection” is such a sanitized way of saying they died/had fewer children.)

This indicates that a recently admixed population may have more health issues than its parents, but the issues will work themselves out over time.

Just about the best thing I could find today (light and BMI):

“The results of this study demonstrate that the timing of even moderate intensity light exposure is independently associated with BMI. Specifically, having a majority of the average daily light exposure above 500 lux (MLiT500) earlier in the day was associated with a lower BMI. In practical terms, for every hour later of MLiT500 in the day, there was a 1.28 unit increase in BMI. The complete regression model (MLiT500, age, gender, season, activity level, sleep duration and sleep midpoint) accounted for 34.7% of the variance in BMI. Of the variables we explored, MLiT500 contributed the largest portion of the variance (20%).”

From “Timing and Intensity of Light Correlate with Body Weight in Adults” by Kathryn J. Reid, Giovanni Santostasi, Kelly G. Baron, John Wilson, Joseph Kang, and Phyllis C. Zee.