Primates managed to keep most of their neurons the same size

Friday, August 10th, 2018

Eugène Dubois gathered the brain and body weights of several dozen animal species and calculated the mathematical rate at which brain size expands relative to body size:

Dubois reasoned that as body size increases, the brain must expand for reasons of neural housekeeping: Bigger animals should require more neurons just to keep up with the mounting chores of running a larger body. This increase in brain size would add nothing to intelligence, he believed. After all, a cow has a brain at least 200 times larger than a rat, but it doesn’t seem any smarter. But deviations from that mathematical line, Dubois thought, would reflect an animal’s intelligence. Species with bigger-than-predicted brains would be smarter than average, while those with smaller-than-predicted brains would be dumber. Dubois’s calculations suggested that his Java Man was indeed a smart cookie, with a relative brain size — and intelligence — that fell somewhere between modern humans and chimpanzees.

Dubois’s formula was later revised by other scientists, but his general approach, which came to be known as “allometric scaling,” persisted. More modern estimates have suggested that the mammalian brain mass increases by an exponent of two-thirds compared to body mass. So a dachshund, weighing roughly 27 times more than a squirrel, should have a brain about 9 times bigger — and in fact, it does. This concept of allometric scaling came to permeate the discussion of how brains relate to intelligence for the next hundred years.

Seeing this uniform relationship between body and brain mass, scientists developed a new measure called encephalization quotient (EQ). EQ is the ratio of a species’s actual brain mass to its predicted brain mass. It became a widely used shorthand for intelligence. As expected, humans led the pack with an EQ of 7.4 to 7.8, followed by other high achievers such as dolphins (about 5), chimpanzees (2.2 to 2.5), and squirrel monkeys (roughly 2.3). Dogs and cats fell in the middle of the pack, with EQs of around 1.0 to 1.2, while rats, rabbits, and oxen brought up the rear, with values of 0.4 to 0.5. This way of thinking about brains and intelligence has been “very, very dominant” for decades, says Evan MacLean, an evolutionary anthropologist at the University of Arizona in Tucson. “It’s sort of a fundamental insight.”

Comparative EQ

A century later, Suzana Herculano-Houzel found a (gruesome) way to count neurons efficiently:

An entire rat brain contains about 200 million nerve cells.

She looked at brains from five other rodents, from the 40-gram mouse to the 48-kilogram capybara (the largest rodent in the world, native to Herculano-Houzel’s home country of Brazil). Her results revealed that as brains get larger and heavier from one species of rodent to another, the number of neurons grows more slowly than the mass of the brain itself: A capybara’s brain is 190 times larger than a mouse’s, but it has only 22 times as many neurons.

Then in 2006, Herculano-Houzel got her hands on the brains of six primate species during a visit with Jon Kaas, a brain scientist at Vanderbilt University in Nashville, Tennessee. And this is where things got even more interesting.

[...]

As the primate brain expands from one species to another, the number of neurons rises quickly enough to keep pace with the growing brain size. This means that the neurons aren’t ballooning in size and taking up more space, as they do in rodents. Instead, they stay compact. An owl monkey, with a brain twice as large as a marmoset, actually has twice as many neurons — whereas doubling the size of a rodent brain often yields only 20 to 30 percent more neurons. And a macaque monkey, with a brain 11 times larger than a marmoset, has 10 times as many nerve cells.

[...]

The usual curse of an ever-expanding neuron size may stem from the basic fact that brains function as networks in which individual neurons send signals to one another. As brains get bigger, each nerve cell must stay connected with more and more other neurons. And in bigger brains, those other neurons are located farther and farther away.

[...]

A large rodent called an agouti has eight times as many cortical nerve cells as a mouse, while its white matter takes up an astonishing 77 times as much space. But a capuchin monkey, with eight times as many cortical neurons as a small primate called a galago, has only 11 times as much white matter.

[...]

Kaas thinks that primates managed to keep most of their neurons the same size by shifting the burden of long-distance communication onto a small subset of nerve cells. He points to microscopic studies showing that perhaps 1 percent of neurons do expand in big-brained primates: These are the neurons that gather information from huge numbers of nearby cells and send it to other neurons that are far away. Some of the axons that make these long-distance connections also get thicker; this allows time-sensitive information, such as a visual image of a rapidly moving predator, or prey, to reach its destination without delay. But less-urgent information — that is, most of it — is sent through slower, skinnier axons. So in primates, the average thickness of axons doesn’t increase, and less white matter is needed.

This pattern of keeping most connections local, and having only a few cells transmit information long-distance, had huge consequences for primate evolution. It didn’t merely allow primate brains to squeeze in more neurons. Kaas thinks that it also had a more profound effect: It actually changed how the brain does its work. Since most cells communicated only with nearby partners, these groups of neurons became cloistered into local neighborhoods. Neurons in each neighborhood worked on a specific task — and only the end result of that work was transmitted to other areas far away. In other words, the primate brain became more compartmentalized. And as these local areas increased in number, this organizational change allowed primates to evolve more and more cognitive abilities.

All mammal brains are divided into compartments, called “cortical areas,” that each contain a few million neurons. And each cortical area handles a specialized task: The visual system, for example, includes different areas for spotting the simple edges of shapes and for recognizing objects. Rodent brains don’t seem to become more compartmentalized as they get larger, says Kaas. Every rodent from the bite-sized mouse to the Doberman-sized capybara has about the same number of cortical areas — roughly 40. But primate brains are different. Small primates, such as galagos, have around 100 areas; marmosets have about 170, macaques about 270 — and humans around 360.

We call them flying saltshakers of death

Wednesday, August 8th, 2018

Imagine emerging into the sun after 17 long years spent lying underground, Ed Yong suggests, only for your butt to fall off:

That ignominious fate regularly befalls America’s cicadas. These bugs spend their youth underground, feeding on roots. After 13 or 17 years of this, they synchronously erupt from the soil in plagues of biblical proportions for a few weeks of song and sex. But on their way out, some of them encounter the spores of a fungus called Massospora.

A week after these encounters, the hard panels of the cicadas’ abdomens slough off, revealing a strange white “plug.” That’s the fungus, which has grown throughout the insect, consumed its organs, and converted the rear third of its body into a mass of spores. The de-derriered insects go about their business as if nothing unusual has happened. And as they fly around, the spores rain down from their exposed backsides, landing on other cicadas and saturating the soil. “We call them flying saltshakers of death,” says Matt Kasson, who studies fungi at West Virginia University.

Massospora and its butt-eating powers were first discovered in the 19th century, but Kasson and his colleagues have only just shown that it has another secret: It doses its victims with mind-altering drugs. Perhaps that’s why “the cicadas walk around as if nothing’s wrong even though a third of their body has fallen off,” Kasson says.

[...]

Greg Boyce, a member of Kasson’s team, looked at all the chemicals found in the white fungal plugs of the various cicadas. And to his shock, he found that the banger-wings were loaded with psilocybin—the potent hallucinogen found in magic mushrooms. “At first, I thought: There’s absolutely no way,” he says. “It seemed impossible.” After all, no one has ever detected psilocybin in anything other than mushrooms, and those fungi have been evolving separately from Massospora for around 900 million years.

The surprises didn’t stop there. “I remember looking over at Greg one night and he had a strange look on his face,” Kasson recalls. “He said, ‘Have you ever heard of cathinone?’” Kasson hadn’t, but a quick search revealed that it’s an amphetamine. It had never been found in a fungus before. Indeed, it was known only from the khat plant that has long been chewed by people from the Middle East and the Horn of Africa. But apparently, cathinone is also produced by Massaspora as it infects periodical cicadas.

[...]

Infected cicadas behave strangely. Despite their horrific injuries, males become hyperactive and hypersexual. They frenetically try to mate with anything they can find, including with other males. They’ll even mimic the wing-flicking signals of females to lure males toward them. None of this does them any good—their genitals have either been devoured by the fungus or have fallen off with the rest of their butts. Instead, this behavior only benefits the fungus, allowing its spores to find new hosts.

Kasson suspects that cathinone and psilocybin are responsible for at least some of these behaviors. “If I had a limb amputated, I probably wouldn’t have a lot of pep in my step,” he said. “But these cicadas do. Something is giving them a bit more energy. The amphetamine could explain that.”

Psilocybin’s role is harder to explain. The drug might make humans hallucinate, but no one knows if cicadas would similarly trip. There is, however, a theory that magic mushrooms evolved psilocybin to reduce the appetites of insects that might compete with them for decaying wood. Perhaps by suppressing the appetites of cicadas, Massospora nudges them away from foraging and toward incessant mating.

There are many parasitic fungi that manipulate the behavior of insect hosts, including the famous Ophiocordyceps fungi, which can turn ants into zombies.

This is how a zombie outbreak could (semi-plausibly) happen.

How do placebos work?

Saturday, August 4th, 2018

Using lab tools to activate the brain’s reward circuit in mice empowered the immune system to fight tumors:

Clues emerged in brain imaging experiments published a decade ago. Those analyses revealed that the same reward circuit activated by food, sex and social interactions (as well as gambling and addictive drugs) is also turned on in people who respond to placebos. Puzzling over those data, researchers in Israel turned the mind-body question into an easier-to-measure physiological one: Would activation of the reward circuit have any effect on the immune system?

It seemed fair to assume positive thoughts and emotions would alter the activity of neurons in the brain. “And neuronal activity is something we can manipulate,” says biologist Asya Rolls of Technion-Israel Institute of Technology, who was co-senior author of the current study.

In previous work her team stimulated the brains of mice with a relatively new technology called DREADD (designer receptors exclusively activated by designer drugs) that puts a molecular on-off switch on particular cells—in this case, neurons of the reward circuit. After activating a mouse’s reward system, the researchers analyzed immune cells in its spleen. The clearest effects showed up in monocytes—a group of white blood cells that chew up pathogens as part of the body’s non-specific immune defenses. Specifically, the team found that monocytes from brain-activated mice killed bacteria much more effectively than monocytes from untreated animals.

Seeing that the brain’s reward circuit could boost immune activity against pathogens, “our next thought was, what is a situation where the immune system fails?” says Tamar Ben-Shaanan, a biologist now at the University of California, San Francisco who published the bacterial experiments in 2016. Ben-Shaanan and Technion MD-PhD student Maya Schiller are co-lead authors on the new study.

The idea of looking into cancer came from study co-senior author Fahed Hakim, who directs the EMMS Nazareth Hospital and works as a pediatric pulmonologist and sleep specialist at Rambam Health Care Campus in Haifa, Israel. During a research stint at the University of Chicago, Hakim studied mouse models of cancer and published a 2014 study showing that fragmented sleep made the animals’ tumors grow faster. If bad sleep triggers tumor-promoting brain activity, Hakim says, it seemed reasonable to think that activating the reward pathway might produce the opposite effect—brain changes that slow cancer.

And that’s what the researchers found. In mice with implanted cancer cells, two weeks of daily reward circuit stimulation produced a powerful response—their tumors were 40 to 50 percent smaller than those in control mice that didn’t get the brain activation. Further experiments traced this effect to a specific group of immune cells made in the bone marrow called myeloid-derived suppressor cells (MDSCs). If left unhindered, MDSCs promote tumor growth by shutting down other immune cells that keep tumors in check. However, activating the brain’s reward system unleashes chemical signals that thwart this web of checks and balances in a manner that disables these pro-tumor MDSCs. That, in turn, allows typical anti-tumor immune responses to proceed.

An old tuberculosis vaccine can reverse Type 1 diabetes

Wednesday, August 1st, 2018

The 100-year-old BCG vaccine against tuberculosis can reverse Type 1 diabetes to almost undetectable levels, an eight-year study has shown:

Used for almost a century to prevent tuberculosis, the BCG vaccine helps boost and regulate the immune system. The team also discovered that the jab speeds up the rate by which cells convert glucose into energy and tests on mice show that it could also be beneficial against Type 2 diabetes.

The new study involved 52 people with Type 1 diabetes. After three years of treatment average blood sugar levels had dropped by 10 per cent and by 18 per cent after four years. Treated participants had an average blood glucose score of 6.65, close to the 6.5 considered the threshold for diabetes diagnosis.

In comparison, the blood sugar of those in the placebo group continued to rise over the trial period.

Liquid water offers hope on Mars

Friday, July 27th, 2018

Radar observations have revealed what appears to be a buried lake on Mars:

Discovered by a team of Italian scientists using three year’s worth of data from the Mars Advanced Radar for Subsurface and Ionosphere Sounding (MARSIS) instrument on the European Space Agency’s Mars Express orbiter, the potential lake is at least a few meters deep, and might be a fixed, steady feature of the subsurface. If confirmed, this would be the first-known reservoir of liquid water on present-day Mars—a keystone in the search for past or even present life on the Red Planet, potentially offering fresh clues about how Earth’s neighbor so profoundly transformed billions of years ago from a warmer, wetter world to its current freeze-dried state. Announced today at a press conference in Rome, the results are detailed in a study appearing in the July 26 edition of Science. Although this is just one detection, the team wrote, “there is no reason to conclude that the presence of subsurface water on Mars is limited to a single location.”

“The presence of a body of liquid water beneath Mars’s south polar cap has various implications, opening new possibilities for the existence of microorganisms in the Martian environment,” says Sebastian Lauro, a study co-author based at Roma Tre University in Rome. “Moreover, it provides a valuable confirmation that the water that once flowed abundantly over the Martian surface in the form of seas, lakes and rivers filled the voids in the subsurface.”

For the past 12 years MARSIS has mapped the Martian underground using beams of low-frequency radar pulses, which can penetrate up to several kilometers beneath the surface. Although they pass relatively unscathed through most substances, these pulses reflect back up to the spacecraft each time they encounter boundaries between different materials, such as the interface of ice and bedrock. That reflection is particularly strong at interfaces with liquid water, and shows up as a distinctively bright spot in visualizations of the data. Following up on preliminary detections of bright spots beneath Mars’s southern ice cap dating back to 2007, the Italian team reprogrammed MARSIS to employ a more intensive scanning mode, then surveyed Planum Australe 29 times with the instrument between 2012 and 2015. Time and time again across the entire observing campaign the new MARSIS readings revealed a consistent 20-kilometer-wide bright spot nestled in a bowl-like depression beneath the ice cap in Planum Australe—a feature consistent with a sizable body of liquid water (or, to be fair, with water-saturated sediments more akin to subterranean sludge). The team then spent almost a year analyzing the data, and another two years writing their paper and attempting to rule out non-aqueous explanations for what they had seen.

Billions of years ago, Mars was a much more Earth-like place where water pooled in seas, carved enormous canyons and bubbled from hot springs. Life, many astrobiologists speculate, may have had no difficulty getting started there. But early in its promising existence the planet somehow lost its way, transforming into a desiccated orb of dried-up ocean-, river- and lakebeds. Robotic missions to the planet’s surface still find surprising echoes of that bygone time, such as patches of water-ice frost forming on rocks as well as water droplets condensing like dew on a lander’s leg. Orbiters, too, have glimpsed what might be rivulets of water flowing down sun-bathed crater walls at the height of Martian summer. Perhaps life, too, has managed to endure in some diminished, limited way. But, if so, it would have to contend with a world in which all moisture quickly vanishes in the thin, cold air, leaving the surface dry as a bone. Still, the water that once flowed across the land had to go somewhere. Some of it was likely lost to space, due to Mars’s diminutive gravitational field, but a significant fraction of the planet’s aqueous inventory never really left, instead just freezing belowground. Now it appears not all of that buried watery wealth is frozen after all.

“The really exciting thing is that this is a stable body of liquid water that was observed in the radar data over three years, not just droplets that have been observed over a short period of time,” says Anja Diez, a glaciologist at the Norwegian Polar Institute who wrote an accompanying commentary about the discovery. The subsurface lake, Diez says, may be similar those found via radar-sounding on Earth beneath ice sheets in Antarctica and Greenland.

You can learn a lot from humans and their stuff

Thursday, July 26th, 2018

You can learn a lot from humans and their stuff, it turns out:

Formal training programs, which can be called education, enhance cognition in human and nonhuman animals alike. However, even informal exposure to human contact in human environments can enhance cognition.

We review selected literature to compare animals’ behavior with objects among keas and great apes, the taxa that best allow systematic comparison of the behavior of wild animals with that of those in human environments such as homes, zoos, and rehabilitation centers.

In all cases, we find that animals in human environments do much more with objects. Following and expanding on the explanations of several previous authors, we propose that living in human environments and the opportunities to observe and manipulate human-made objects help to develop motor skills, embodied cognition, and the use of objects to extend cognition in the animals. Living in a human world also furnishes the animals with more time for such activities, in that the time needed for foraging for food is reduced, and furnishes opportunities for social learning, including emulation, an attempt to achieve the goals of a model, and program-level imitation, in which the imitator reproduces the organizational structure of goal-directed actions without necessarily copying all the details. All these factors let these animals learn about the affordances of many objects and make them better able to come up with solutions to physical problems.

The kea is a large parrot found in the mountains of the South Island of New Zealand — and it’s pretty freakin’ smart.

(Hat tip to Tyler Cowen.)

From senescence to apoptosis

Tuesday, July 24th, 2018

Cells pick up damage all the time:

If the damage is sufficiently critical, the cell will respond by committing an orderly sort of suicide called apoptosis, which keeps it from causing any further problems. For lesser damage, there’s a less drastic alternative called senescence, in which the cell remains active and contributes its normal functions to the organism’s health, but it commits to no longer dividing. Over time, as animals age, more and more cells enter senescence, a process that’s thought to contribute to aging.

But it has gradually become apparent that senescent cells don’t just continue performing their normal function. They also produce a set of senescence-specific signaling molecules that can influence cells elsewhere in the body, including some that can trigger inflammation. The new work is based on the hypothesis that these signaling molecules might contribute to the changes that are associated with aging.

To test this, a large team of researchers did a relatively straightforward experiment: take senescent cells and implant them in an otherwise young and healthy mouse.

The authors chose fat cells, which typically don’t trigger an immune response when transplanted to a new animal. To get lots of senescent cells, they induced DNA damage, using either a drug or radiation (both produced similar results). While it would have been more relevant to obtain senescent cells from an older mouse, this allowed them to obtain lots of the cells they needed to do the experiments.

At various times after the transplant, the team measured a series of physical traits that change with age: average walking speed, muscle strength, endurance on a treadmill, time spent active, food intake and body weight. And while some of these didn’t change after the senescent cells were transplanted in, the young mice had clearly lost some strength by a month after the transplant: walking speed, endurance, and grip strength were all down significantly.

This change comes despite the fact that only about one in 10,000 cells in the body were senescent, transplanted cells. Obviously, this suggests that the cells are having an effect by talking to all the healthy ones around them. In fact, the researchers found that the transplanted cells’ presence seemed to cause some of the young animal’s cells to become senescent, amplifying their effect. Other experiments showed that the transplanted cells had stronger effects if the recipient was older or eating a high-fat diet.

For older mice receiving transplanted cells, one of the consequences was an increased chance of death. Risk of mortality was up by 5.2 fold, and there was no single cause of death or pathology that was increased by a similar amount. Instead, the animals just seemed to be less healthy.

At this point, the researchers shift focus to what they call a “senolytic agent.” That bit of jargon refers to a combination of two chemicals that cause senescent cells to die, possibly by shifting them from the senescence response over into the cell death response. The chemicals in question are quercetin, something found in a huge variety of plants (anyone who eats any vegetables undoubtedly ingests some of this every day). The second is called dasatinib, and you’re very unlikely to come across this as part of your diet, since it’s normally used as chemotherapy.

The combo of the two chemicals did what you’d expect. If they were administered immediately after the senescent cells were transplanted, the chemicals helped limit the cells’ impact on strength and endurance. For mice that were simply aging normally, the two chemicals also helped limit the loss of strength and endurance, and increased the animals’ daily activity relative to controls. In addition, the chemicals increased the average lifespan by 36 percent.

The physical strength of nations varies considerably

Tuesday, July 17th, 2018

I was watching the latest CrossFit documentary on Netflix, The Redeemed and the Dominant, and this reminded me of Anatoly Karlin’s piece on the (physical) strength of nations, which looks at the stereotype that Northerners are stronger than Southerners:

The average Germanic seems to be around 15 years “younger” than the average Italian or Spaniard in terms of hand grip strength. These are remarkably big differences, around 1 S.D.’s worth. Average German, Swede, or Pole might have a 15 SQ (strength quotient) advantage over the average South European.

For context, there is a ~2.5 S.D. difference in male and female grip strength.

Women have around 60% of the hand grip strength of men. Huge difference… but remarkably, seems to be about equal to the difference between developed Anglo-German/Slavic Europe and the Indian subcontinent!

Why do so many of these studies focus on grip strength? Because it is easy to measure, changes the least as people age (hand grip is the last to go), and is exercised more or less universally.

My best guess is that in terms of S.D.’s it goes something like this in terms of hand grip strength (Flynn! denotes members of those ethnicities that dwell in First World environments).

  • +1 Icelanders
  • +0.5 Steppe!East Asians (i.e.Mongols)
  • 0 Balto-Slavic-Germanics, Flynn!WestAfricans
  • -.5 East Asians
  • -1 Mediterraneans, Flynn!Indians, WestAfricans
  • -2 Indians

Icelanders, with a mere 300,000 people, dominate the world strongman competitions. They have won 9 Gold medals, more than any other country other than the US, which has won 11 (and has ONE THOUSAND times its population).

Icelandic women have also won four years of the past decade’s worth the Crossfit Games.

Liquid fluorine is spectacular

Saturday, July 14th, 2018

There was a time when rocket designers felt comfortable proposing propellants that would be considered insane today:

One of these was fluorine, an oxidizer so powerful that it will oxidize oxygen. Liquified it is denser than LOX and provides a higher specific impulse than LOX when burned with the same fuels. On paper, liquid fluorine is spectacular. In reality, fluorine is toxic and just about all of the combustion compounds are toxic (burn it with hydrogen and you get hydrofluoric acid, which will eat your bones). Fluorine has the added bonus that it will merrily combust with a whole lot of structural materials, so you have to be careful in your design and preparation for tanks, pumps, lines, etc.

Consequently, it was important to know your stuff. To that end, Douglas Missile & Space Systems Division produced a Fluorine Systems Handbook.

Display invites attention

Thursday, July 12th, 2018

Heather E. Heying discusses toxic femininity:

Sex and gender roles have been formed over hundreds of thousands of years in human evolution, indeed, over hundreds of millions of years in our animal lineage. Aspects of those roles are in rapid flux, but ancient truths still exist. Historical appetites and desires persist. Straight men will look at beautiful women, especially if those women are a) young and hot and b) actively displaying. Display invites attention.

Hotness-amplifying femininity puts on a full display, advertising fertility and urgent sexuality. It invites male attention by, for instance, revealing flesh, or by painting on signals of sexual receptivity. This, I would argue, is inviting trouble. No, I did not just say that she was asking for it. I did, however, just say that she was displaying herself, and of course she was going to get looked at.

The amplification of hotness is not, in and of itself, toxic, although personally, I don’t respect it, and never have. Hotness fades, wisdom grows — wise young women will invest accordingly. Femininity becomes toxic when it cries foul, chastising men for responding to a provocative display.

Where we set our boundaries is a question about which reasonable people might disagree, but two bright-lines are widely agreed upon: Every woman has the right not to be touched if she does not wish to be; and coercive quid pro quo, in which sexual favors are demanded for the possibility of career advancement, is unacceptable. But when women doll themselves up in clothes that highlight sexually-selected anatomy, and put on make-up that hints at impending orgasm, it is toxic — yes, toxic — to demand that men do not look, do not approach, do not query.

Young women have vast sexual power. Everyone who is being honest with themselves knows this: Women in their sexual prime who are anywhere near the beauty-norms for their culture have a kind of power that nobody else has. They are also all but certain to lack the wisdom to manage it. Toxic femininity is an abuse of that power, in which hotness is maximized, and victim status is then claimed when straight men don’t treat them as peers.

Creating hunger in men by actively inviting the male gaze, then demanding that men have no such hunger — that is toxic femininity. Subjugating men, emasculating them when they display strength — physical, intellectual, or other — that is toxic femininity. Insisting that men, simply by virtue of being men, are toxic, and then acting surprised as relationships between men and women become more strained — that is toxic femininity. It is a game, the benefits of which go to a few while the costs are shared by all of us.

The best design uses gears from the middle of the list

Wednesday, July 11th, 2018

I was recently reminded of Feynman’s anecdote about an early wartime engineering job he had, and I finally got around to pulling my copy of Surely You’re Joking off the shelf to transcribe it:

Near the end of the summer I was given my first real design job: a machine that would make a continuous curve out of a set of points — one point coming in every fifteen seconds — from a new invention developed in England for tracking airplanes, called “radar.” It was the first time I had ever done any mechanical designing, so I was a little bit frightened.

I went over to one of the other guys and said, “You’re a mechanical engineer; I don’t know how to do any mechanical engineering, and I just got this job…”

“There’s nothin’ to it,” he said. “Look, I’ll show you. There’s two rules you need to know to design these machines. First, the friction in every bearing is so-and-so much, and in every gear junction, so-and-so much. From that, you can figure out how much force you need to drive the thing. Second, when you have a gear ratio, say 2 to 1, and you are wondering whether you should make it 10 to 5 or 24 to 12 or 48 to 24, here’s how to decide: You look at the Boston Gear Catalogue, and select those gears that are in the middle of the list. The ones at the high end have so many teeth they’re hard to make. If they could make gears with even finer teeth, they’d have made the list go even higher. The gears at the low end of the list have so few teeth they break easy. So the best design uses gears from the middle of the list.”

I had a lot of fun designing that machine. By simply selecting the gears from the middle of the list and adding up the little torques with the two numbers he gave me, I could be a mechanical engineer!

Fine like powder, but sharp like glass

Saturday, July 7th, 2018

When the Apollo astronauts returned from the Moon, the dust that clung to their spacesuits made their throats sore and their eyes water:

The “lunar hay fever”, as NASA astronaut Harrison Schmitt described it during the Apollo 17 mission created symptoms in all 12 people who have stepped on the Moon. From sneezing to nasal congestion, in some cases it took days for the reactions to fade. Inside the spacecraft, the dust smelt like burnt gunpowder.

[...]

Lunar dust has silicate in it, a material commonly found on planetary bodies with volcanic activity. Miners on Earth suffer from inflamed and scarred lungs from inhaling silicate. On the Moon, the dust is so abrasive that it ate away layers of spacesuit boots and destroyed the vacuum seals of Apollo sample containers.

Fine like powder, but sharp like glass. The low gravity of the Moon, one sixth of what we have on Earth, allows tiny particles to stay suspended for longer and penetrate more deeply into the lung.

“Particles 50 times smaller than a human hair can hang around for months inside your lungs. The longer the particle stays, the greater the chance for toxic effects,” explains Kim.

The potential damage from inhaling this dust is unknown but research shows that lunar soil simulants can destroy lung and brain cells after long-term exposure.

On Earth, fine particles tend to smoothen over years of erosion by wind and water, lunar dust however, is not round, but sharp and spiky.

In addition the Moon has no atmosphere and is constantly bombarded by radiation from the Sun that causes the soil to become electrostatically charged.

This charge can be so strong that the dust levitates above the lunar surface, making it even more likely to get inside equipment and people’s lungs.

I’m beginning to think the Moon might be inhospitable.

Absolute thinking predicts mental illness

Tuesday, July 3rd, 2018

Mohammed Al-Mosaiwi explains absolute thinking:

The term cognitive miser, first introduced by the American psychologists Susan Fiske and Shelley Taylor in 1984, describes how humans seek the simplest and least effortful ways of thinking. Nuance and complexity is expensive — it takes up precious time and energy — so wherever possible we try to cut corners. This is why we have biases and prejudices, and form habits. It’s why the study of heuristics (intuitive ‘gut-feeling’ judgments) is so useful in behavioural economics and political science.

[...]

In a recent research article in Clinical Psychological Science, I and my collaborator, the neuroscientist Tom Johnstone at the University of Reading in the UK, examined the prevalence of absolutist thinking in the natural language of more than 6,400 online members in various mental-health chat groups. From the outset, we predicted that those with depression, anxiety and suicidal ideation would have a more absolutist outlook, and that this would manifest in their style of language. Compared with 19 different online control chat groups on topics from cancer to parenting, the prevalence of absolutist words was approximately 50 per cent greater in depression and anxiety groups, and approximately 80 per cent greater in the suicidal-ideation group.

Previously, the best-known linguistic markers for mental-health disorders had been an excessive use of first-person singular pronouns such as ‘me’, ‘myself’ and ‘I’, with a reduced use of second- and third-person pronouns. This pattern of pronoun use reflects the isolation and self-focus common in depression. Negative-emotion words are also a strong linguistic marker for mental-health disorders, however researchers have reported that pronouns are actually more reliable in identifying depression. We find that the prevalence of absolutist words is a better marker than both pronouns and negative-emotion words.

Confrontational tension and fear make most violence incompetent

Saturday, June 2nd, 2018

Violence is difficult to carry out, Randall Collins reminds us:

This is the main finding of research on what happens when humans find themselves in situations threatening violence. It runs contrary to our cultural beliefs, and the way violence is depicted in the news and entertainment media. But the news reports violence that happens, not fights that abort, angry quarrels that fritter out, or guns that are pointed but not fired, or fired but miss. Films and TV shows make violence look dramatic, but if they showed what it actually looks like no one would want to watch it.

He summarizes his own Violence: A Micro-Sociological Theory:

Confrontational tension and fear: In situations threatening violence, participants may start out with angry bluster, loud voices, and menacing gesture. But when it comes to bodily attack on their opponent, even the most aggressive show tension and fear on their faces. This tension makes most violence incompetent. Soldiers and cops who are proficient on a firing range often miss when their target is a live human being; gang-bangers are even more incompetent, firing wildly and quickly running or driving away.

Micro-sociology triggers physiology, and bodily reactions get in the way of conscious intentions. Face-to-face confrontations are socially tense, pumping adrenaline, the flight-or-fight hormone, an undifferentiated arousal that can go either way. Many soldiers in combat do not fire their guns. Like cops in shoot-outs, those who do fire often have perceptual distortions, time slowing to dream-like or speeding up to a blur, a sound-proof tunnel where shooters can’t hear their own guns. Some freeze; some hit their own side in friendly fire; some go into a frenzy where they can’t stop firing in an overkill of bullets until they have emptied their magazine. The same applies to fists, kicks, or knife-stabs. The common denominator is high adrenaline levels, which mobilize the large muscles of the body but desensitize fine motor control of hands and fingers.

What happens in a confrontation depends on the relative levels of adrenaline on both sides. If one side can stay in the zone of medium arousal while the other loses bodily control, the more competent performer at violence will beat the incompetent performer. Not that the better fighter at the moment has to be really competent, just less incompetent than the other. At the extreme, one side becomes paralyzed at very high adrenaline levels, making an easy target for the opponent still capable of attacking.

To be skilled in violence is to keep your own adrenaline level down to medium levels, while driving up your opponent’s to high levels that make them incompetent. If adrenaline levels are equal, neither side performs worse than the other, and the confrontation stalls out, the fight aborting or winding down by losing momentum. We see this also in sexual aggression.

Attacking the weak: Confrontational tension and fear (ct/f ) is a barrier that aggressors have to overcome if they are to deliver any violence. There are several ways around this barrier. The most common pattern is attacking a weak victim: someone who is physically much weaker; someone who is unarmed when you are armed; someone who is running away. Outnumbering the opponent is a major confidence-booster. In photos of riots and brawls, the most common pattern is a group of between 3 and 6 attackers hitting and kicking an isolated individual. Without this advantage, evenly matched fights usually are stalemates, coming to nothing or quickly aborting; Having even one supporter on the weaker side shifts the emotional balance.

The advantage is not so much physical but emotional domination. Robbers with guns are nevertheless wary of hold-ups where one is a lone individual outnumbered by victims and bystanders; most successful robberies consist of 2 or 3 robbers against an isolated shop-keeper. Back-up in robberies is confidence-building, and a way to establish emotional dominance over the victim. Even police act this way; the more police on the scene, the more likely they are to commit extensive violence in making arrests. Successful violence comes from establishing the mood and rhythm from the outset, driving the opponent into passivity.

Confrontation-minimizing tactics: Another way around the barrier of ct/f is to avoid the main source of tension: threatening the other person face-to-face. Eye contact makes the encounter tense. Robbers and muggers find it easiest to attack from behind, where the two sides cannot see each other’s eyes. Wearing masks and hoods emboldens the attacker and disconcerts victims by making the attacker appear un-human. And in the modern high-tech world, cyber attacks are psychologically easy, since they involve no human confrontation at all.

Audience support: Onlookers who encourage a fight help overcome ct/f and enable fighters to carry on much longer than they would if there were no one watching. How long and severe the fight is depends on the size and attitude of the audience: most destructive where a large audience is unified in cheering on a fight; shorter and less harmful when the audience is divided or unsure; when bystanders ignore a fight it soon peters out.

Violence as fun and entertainment: Fights are particularly likely on occasions of leisure and fun: parties, drinking places, holidays, crowds at games and concerts. These are carousing zones where normal routines are suspended and special excitement is expected. Violence on these occasions still requires overcoming ct/f, finding emotional domination over weak victims, and/or support of an audience.

With the recent scandals in the news, he goes on to ask, Do the conditions for successful violence apply also to sexual violence? and supplies some examples where confrontational tension and fear play a large role:

A young man in his late teens followed an attractive middle-aged woman into her apartment building, by hurrying through the security door behind her. No one else is in the lobby. In the elevator he pulls a knife and threatens to rape her. Although a small woman (5 foot 2 inches), she is a top executive in a non-profit organization, used to exercising authority. She says disapprovingly, what would your mother think if she knew what you are doing? When the elevator door opened, he runs off.

A tall (5 foot 9 inches), attractive woman in her mid-20s is running in an open area, when a man about her age runs up behind her and grabs her. She turns around and swings at him, knocking off his glasses and breaking them. (What did he look like?) About six feet tall, long hair and mustache, medium build. He immediately starts apologizing. She steps on his glasses, and glares at him as he retreats.

The tables turned when the rapist fails to establish emotional domination. In the previous case, the attacker has a knife, but as in hold-ups, a weapon is not enough to be successful unless the victim is intimidated.

Short of rape, milder forms of sexual aggression often fail, perhaps most of the time. David Grazian’s research on night clubs found that male patrons often engage in “the girl hunt,” seeking pickups. But these young men did more talking among themselves about the women they saw than actually making contact with them. Generally they lowered their sights to getting phone numbers, not too successfully at that; and groups of young women who went to clubs together often gave them fake numbers. In other words, even in venues explicitly themed for sexual encounters, most of the “girl hunters” stayed on the sidelines, did not approach aggressively, and were rarely successful.

Is this true across the spectrum of sexual aggression? Accounts in the news media focus on aggressions that succeed, but even here we find most aggressors do not get far.

He has much, much more to say on the topic, but here’s his bottom line:

The micro-sociology of violence in general suggests there are pathways by which women can deter sexual aggression. Perhaps surprisingly, such micro-deterrence may be more successful in preventing the extreme forms of sexual violence — bodily rape, than lesser forms like verbal aggression. But we just don’t know, since we have so little evidence covering situations where women silence men’s verbal advances. The common denominators are, extrapolating from violence generally: keep facing your opponent; looking him in the face, head up, as directly as possible; keep calm and strong-voiced as possible; repeat-repeat-repeat to the point of boredom. Even the arch casting-couch rapist, Weinstein, failed in the majority of his documented attempts; and this is consistent with other evidence.

We fight for status, and we fight for belonging

Friday, June 1st, 2018

Former British Army officer Mike Martin’s Why We Fight explores the evolutionary psychology of warfare:

When you dig into it and you look at the data, there’s only two things that are worth risking yourself in war for, as an individual. The first thing is an increase in social status. And the reason why that’s worth risking yourself for is as you rise up the status hierarchy, particularly as a man, and men do most of the fighting, you get more mates, more sexual mates. When you have more mates, you have more children. That’s a reason to risk fighting in war.

But there’s another reason why people fight in war. That’s to ensure that they have membership of an in-group. This in-group could be a tribe or a nation-state. It’s the same mechanism, it’s the thing that causes us as humans to feel belonging. It’s the thing that makes you feel homesick. It’s the thing that sends shivers down your spine when you’re at a political rally, or a football match, or you’re singing in a choir in church. These are the mechanisms in your brain causing you to seek to belong.

In evolutionary terms, we need to belong to groups because they’re safe. The main reason that groups exist in evolutionary terms is because they protect us from other humans who are trying to kill us. We fight for status and we fight for belonging. We’ve got these ideas that these two things, status and belonging, and humans seeking those things are what cause individuals to fight in wars.

Actually, this makes sense. Look around the world. We’ve got two global level politicians and the idea of them seeking status and having status disputes with each other is very obvious in their behaviour. Leaders seek to dominate their own groups and that’s what they do. Running for the presidency of the United States is a massive status contest, it’s gruelling.

These people are driven to succeed and they’re driven to achieve high status. The mechanism that guides this seeking status is basically testosterone. The way it works is that the more testosterone you get, the more you seek status, but it’s a feedback loop. It’s a positive feedback loop.

When you get to the top of your group, i.e. you become the leader of your country or perhaps you become the head of your tribe, it depends what scale we’re looking at, you then seek to dominate other leaders who are the leaders of other groups. This is where we see wars at a product of a status disputes between leaders playing out.

Belonging comes into play when those who aren’t leaders seek to take part in wars. We can see this played out and the rise of identity politics at the moment, particularly in the States, but also across Europe. If Why We Fight is correct and war is driven by status and belonging, we’re entering a very dangerous period of history.”

Martin has much more to say on his own site. You may recognize him from his appearance in Adam Curtis’s Bitter Lake:

(Hat tip to Scott Adams.)