Does owning a car hurt your health?

February 20th, 2020

Does owning a car hurt your health? To really answer that, you’d need a randomized trial:

But who’s going to assign long-term car ownership on the basis of a coin flip?

The city of Beijing, it turns out. Because of mounting congestion, Beijing has limited the number of new car permits it issues to 240,000 a year since 2011. Those permits are issued in a monthly lottery with more than 50 losers for every winner – and that, as researchers from the University of California Berkeley, Renmin University in China and the Beijing Transport Institute recently reported in the British Medical Journal, provides an elegant natural experiment on the health effects of car ownership.

Led by Berkeley economist Michael Anderson, the researchers followed 180 permit winners and 757 losers for roughly five years, and looked for differences caused by the acquisition of a car.

“The randomization of the lottery is what gives us confidence,” Anderson explained in a statement. “We know that the winners should be comparable to the losers on all attributes other than car ownership.”

Not surprisingly, the winners took 2.9 fewer rides a week on Beijing’s dense public-transit network, representing a 45-per-cent drop in usage. They also spent 24.2 fewer minutes each day day walking or biking than the non-winners, a 54-per-cent drop.

You’d expect these behaviour changes to have health impacts. Over all, the winners gained an average of just more than two kilograms, a difference that was not statistically significant. But the effects were more obvious when looking only at winners aged 50 or older: They gained an average of 10.3 kilograms, a statistically significant and worrisome increase.

The revolution in women’s education and work since the 1960s

February 19th, 2020

Human Diversity by Charles MurrayCharles Murray explores the revolution in women’s education and work since the 1960s (in Human Diversity: The Biology of Gender, Race, and Class):

In 1960, a few years before second-wave feminism took off in the United States, only 41 percent of women ages 25–54 were in the labor force. In 2018, that figure stood at 75 percent.

From 1960 to 2018, women went from 1 percent of civil engineers to 17 percent; from 5 percent of attorneys to 35 percent; from 8 percent of physicians to 42 percent.

Not a single woman was the CEO of a Fortune 500 company in 1960, nor would there be any until 1972.34 In 2018, 25 women were Fortune 500 CEOs, among them the chief executives of General Motors, IBM, PepsiCo, Lockheed Martin, Oracle, and General Dynamics.

In 1960, there was one woman in the U.S. Senate. After the 2018 election, there were 25. In the 1960 House of Representatives, there were 19 women. After the 2018 election, there were 102.

[...]

By 2016, 1,082,669 women got bachelor’s degrees compared to 812,669 men—a 33 percent difference.

[...]

In 1960, 20 men got a professional degree for every woman who did. By 1970, the ratio was less than 10 to 1. By 1980, it was less than 3 to 1. In 2005, women caught up with men. Since then, more women have gotten more professional degrees than men in every year. As of 2016, 93,778 women got a professional degree compared to 84,089 men.

It’s time for learning

February 19th, 2020

Children are born curious:

The number of questions a toddler can ask can seem infinite — it is one of the critical methods humans adopt to learn. In 2007, researchers logging questions asked by children aged 14 months to five years found they asked an average of 107 questions an hour. One child was asking three questions a minute at his peak.

But research from Susan Engel, author of The Hungry Mind and a leading international authority on curiosity in children, finds questioning drops like a stone once children start school. When her team logged classroom questions, she found the youngest children in an American suburban elementary school asked between two and five questions in a two-hour period. Even worse, as they got older the children gave up asking altogether. There were two-hour stretches in fifth grade (year 6) where 10 and 11-year-olds failed to ask their teacher a single question.

In one lesson she observed, a ninth grader raised her hand to ask if there were any places in the world where no one made art. The teacher stopped her mid-sentence with, “Zoe, no questions now, please; it’s time for learning.”

The latest research suggests we should be encouraging questions, because curious children do better:

Researchers from the University of Michigan CS Mott Children’s Hospital and the Center for Human Growth and Development investigated curiosity in 6,200 children, part of the US Early Childhood Longitudinal Study.

I’m not sure the causality runs that way.

Even gifted women who are attracted to STEM gravitate toward the life sciences

February 18th, 2020

Men and women have slightly different “cognitive toolboxes,” Charles Murray notes (in Human Diversity: The Biology of Gender, Race, and Class), but they also have different interests, with women more interested in people and men more interested in things. For instance, men aligned with the following:

  • “The prospect of receiving criticism from others does not inhibit me from expressing my thoughts.”
  • A merit-based pay system
  • Having a full-time career
  • Inventing or creating something that will have an impact
  • A salary that is well above the average person’s
  • believe that society should invest in my ideas because they are more important than those of other people in my discipline.”
  • Being able to take risks on my job (–0.41)
  • Working with things (e.g., computers, tools, machines) as part of my job
  • “The possibility of discomforting others does not deter me from stating the facts.”
  • Having lots of money

And women aligned with the following:

  • Having a part-time career for a limited time period
  • Having a part-time career entirely
  • Working no more than 40 hours in a week
  • Having strong friendships
  • Flexibility in my work schedule
  • Community service
  • Having time to socialize
  • Giving back to the community

Human Diversity by Charles MurrayThe men and women surveyed weren’t typical though:

The results I just presented came from members of SMPY’s Cohort 2, born in 1964–67, who at age 13 had tested in the top 0.5 percent of overall intellectual ability: the top 1 in 200.

[...]

The SMPY women were about twice as likely to take STEM majors as the general population of female undergraduates, but this was true of the men also, and so the male-female ratio in STEM degrees among the SMPY sample (1.6) was fractionally higher than the ratio in the general undergraduate population (1.5).

[...]

Even gifted women who are attracted to STEM gravitate toward the life sciences (People-oriented), not math and the physical sciences (Things-oriented). It was not a subtle tendency. Proportionally, males outnumbered females by almost two to one on the Things-oriented sciences, and females outnumbered males by almost two to one on the People-oriented sciences.

It was completely besmeared with blood, which trickled down over their ears, for they had been sacrificing that very day

February 18th, 2020

Discovery and Conquest of Mexico by Bernal Diaz Del CastilloI was recently reminded of Bernal Diaz del Castillo’s first-hand account of the discovery and conquest of Mexico. I read a paperback copy years ago, soon after reading about it in Guns, Germs, and Steel, but I was able to relocate one memorable passage in seconds by searching the e-text for “matted” (which stuck with me):

The hair of their heads was long and matted together, so that it would have been an impossibility to have put it in any shape or order without cutting it off: besides this, it was completely besmeared with blood, which trickled down over their ears, for they had been sacrificing that very day. The nails of their fingers were uncommonly long, and they held down their heads on approaching us, in token of humility. It was told us that these men were greatly revered for their religion.

Searching for “blood” is oddly rewarding:

I have myself heard the very pious Franciscan brother Toribio Motelmea say that it would certainly have been better if we could have avoided spilling so much blood, and the Indians had not given us the cause to do so; but it had this good effect, that all the inhabitants of New Spain became convinced that their idols were nothing but deceitful demons, and they experienced how much happier they were when they discontinued to worship them or sacrifice to them; and it is a fact, that the inhabitants of Cholulla, from that moment, cared very little about their idols: they took down the large one from the principal cu, and either hid it somewhere or destroyed it altogether: we, at least, never saw that one again, and they placed another there in its stead.

[...]

Before we mounted the steps of the great temple, Motecusuma, who was sacrificing on the top to his idols, sent six papas and two of his principal officers to conduct Cortes up the steps. There were 114 steps to the summit, and, as they feared that Cortes would experience the same fatigue in mounting as Motecusuma had, they were going to assist him by taking hold of his arms. Cortes, however, would not accept of their proffered aid. When we had reached the summit of the temple, we walked across a platform where many large stones were lying, on which those who were doomed for sacrifice were stretched out. Near these stood a large idol, in the shape of a dragon, surrounded by various other abominable figures, with a quantity of fresh blood lying in front of it. Motecusuma himself stepped out of a chapel, in which his cursed gods were standing, accompanied by two papas, and received Cortes and the whole of us very courteously. “Ascending this temple, Malinche,” said he to our commander, “must certainly have fatigued you!” Cortes, however, assured him, through our interpreters, that it was not possible for anything to tire us. Upon this the monarch took hold of his hand and invited him to look down and view his vast metropolis, with the towns which were built in the lake, and the other towns which surrounded the city. Motecusuma also observed, that from this place we should have a better view of the great market.

Indeed, this infernal temple, from its great height, commanded a view of the whole surrounding neighbourhood. From this place we could likewise see the three causeways which led into Mexico,—that from Iztapalapan, by which we had entered the city four days ago; that from Tlacupa, along which we took our flight eight months after, when we were beaten out of the city by the new monarch Cuitlahuatzin; the third was that of Tepeaquilla. We also observed the aqueduct which ran from Chapultepec, and provided the whole town with sweet water. We could also distinctly see the bridges across the openings, by which these causeways were intersected, and through which the waters of the lake ebbed and flowed. The lake itself was crowded with canoes, which were bringing provisions, manufactures, and other merchandise to the city. From here we also discovered that the only communication of the houses in this city, and of all the other towns built in the lake, was by means of drawbridges or canoes. In all these towns the beautiful white plastered temples rose above the smaller ones, like so many towers and castles in our Spanish towns, and this, it may be imagined, was a splendid sight.

[...]

Cortes then turned to Motecusuma, and said to him, by means of our interpretress, Doña Marina: “Your majesty is, indeed, a great monarch, and you merit to be still greater! It has been a real delight to us to view all your cities. I have now one favour to beg of you, that you would allow us to see your gods and teules.”

To which Motecusuma answered, that he must first consult his chief papas, to whom he then addressed a few words. Upon this, we were led into a kind of small tower, with one room, in which we saw two basements resembling altars, decked with coverings of extreme beauty. On each of these basements stood a gigantic, fat-looking figure, of which the one on the right hand represented the god of war Huitzilopochtli. This idol had a very broad face, with distorted and furious-looking eyes, and was covered all over with jewels, gold, and pearls, which were stuck to it by means of a species of paste, which, in this country, is prepared from a certain root. Large serpents, likewise, covered with gold and precious stones, wound round the body of this monster, which held in one hand a bow, and in the other a bunch of arrows. Another small idol which stood by its side, representing its page, carried this monster’s short spear, and its golden shield studded with precious stones. Around Huitzilopochtli’s neck were figures representing human faces and hearts made of gold and silver, and decorated with blue stones. In front of him stood several perfuming pans with copal, the incense of the country; also the hearts of three Indians, who had that day been slaughtered, were now consuming before him as a burnt-offering. Every wall of this chapel and the whole floor had become almost black with human blood, and the stench was abominable.

On the left hand stood another figure of the same size as Huitzilopochtli. Its face was very much like that of a bear, its shining eyes were made of tetzcat, the looking-glass of the country. This idol, like its brother Huitzilopochtli, was completely covered with precious stones, and was called Tetzcatlipuca. This was the god of hell, and the souls of the dead Mexicans stood under him. A circle of figures wound round its body, resembling diminutive devils with serpents’ tails. The walls and floor around this idol were also besmeared with blood, and the stench was worse than in a Spanish slaughter-house. Five human hearts had that day been sacrificed to him. On the very top of this temple stood another chapel, the woodwork of which was uncommonly well finished, and richly carved. In this chapel there was also another idol, half man and half lizard, completely covered with precious stones; half of this figure was hidden from view. We were told that the hidden half was covered with the seeds of every plant of this earth, for this was the god of the seeds and fruits: I have, however, forgotten its name, but note that here also everything was besmeared with blood, and the stench so offensive that we could not have staid there much longer. In this place was kept a drum of enormous dimensions, the tone of which, when struck, was so deep and melancholy that it has very justly been denominated the drum of hell. The drum-skin was made out of that of an enormous serpent; its sound could be heard at a distance of more than eight miles. This platform was altogether covered with a variety of hellish objects,—large and small trumpets, huge slaughtering knives, and burnt hearts of Indians who had been sacrificed: everything clotted with coagulated blood, cursed to the sight, and creating horror in the mind. Besides all this, the stench was everywhere so abominable that we scarcely knew how soon to get away from this spot of horrors. Our commander here said, smilingly, to Motecusuma: “I cannot imagine that such a powerful and wise monarch as you are, should not have yourself discovered by this time that these idols are not divinities, but evil spirits, called devils. In order that you may be convinced of this, and that your papas may satisfy themselves of this truth, allow me to erect a cross on the summit of this temple; and, in the chapel, where stand your Huitzilopochtli and Tetzcatlipuca, give us a small space that I may place there the image of the holy Virgin; then you will see what terror will seize these idols by which you have been so long deluded.”

Motecusuma knew what the image of the Virgin Mary was, yet he was very much displeased with Cortes’ offer, and replied, in presence of two papas, whose anger was not less conspicuous, “Malinche, could I have conjectured that you would have used such reviling language as you have just done, I would certainly not have shown you my gods. In our eyes these are good divinities: they preserve our lives, give us nourishment, water, and good harvests, healthy and growing weather, and victory whenever we pray to them for it. Therefore we offer up our prayers to them, and make them sacrifices. I earnestly beg of you not to say another word to insult the profound veneration in which we hold these gods.”

As soon as Cortes heard these words and perceived the great excitement under which they were pronounced, he said nothing in return, but merely remarked to the monarch with a cheerful smile: “It is time for us both to depart hence.” To which Motecusuma answered, that he would not detain him any longer, but he himself was now obliged to stay some time to atone to his gods by prayer and sacrifice for having committed gratlatlacol, by allowing us to ascend the great temple, and thereby occasioning the affronts which we had offered them.

“If that is the case,” returned Cortes, “I beg your pardon, great monarch.” Upon this we descended the 114 steps, which very much distressed many of our soldiers, who were suffering from swellings in their groins. The following is all I can communicate with respect to the size or circumference of this temple; but previously reckon upon the reader’s kind indulgence, if I should make any misstatement; for at the time when all these things were going on, I was thinking of anything but writing a book, but rather how best to fulfil my duty as a soldier, and to act up to the commands of our general Cortes. However, if I remember rightly, this temple occupied a space of ground on which we should erect six of the largest buildings, as they are commonly found in our country. The whole building ran up in rather a pyramidical form, on the summit of which was the small tower with the idols. From the middle of the temple up to the platform there were five landings, after the manner of barbacans, but without any breastworks. A perfect idea of the form of this temple may be gained from the pictures which are in the possession of several of the Conquistadores, (I have one myself,) which every one must have seen by this time. The following is what I learnt respecting the building of this temple. Every inhabitant had contributed his mite of gold, silver, pearls and precious stones thereto. These gifts were then buried in the foundations, and the ground sprinkled with the blood of a number of prisoners of war, and strewed with the seeds of every plant growing in the country. This was done in order that the gods might grant the country conquest, riches, and abundant harvests. The reader will here naturally ask the question: how we got to know that its foundations were thus filled with gold, pearls, silver, precious stones, seeds, and sprinkled with human blood, as this building had stood there for the space of one thousand years? To this I answer, that subsequent to the conquest of this large and strongly fortified city, we found it to be a positive fact; for when new buildings were being erected on the place where this temple stood, a great part of the space was fixed upon for the new church dedicated to our patron Saint Santiago, and the workmen, on digging up the old foundations to give more stability to the new ones, found a quantity of gold, silver, pearls, chalchihuis stones, and other valuable things. A similar discovery was made by a citizen of Mexico, to whom also a portion of this space had been allotted for building-ground, but the treasure was claimed for his majesty; and parties went so far as to commence a lawsuit about it, I cannot however now recollect how it terminated. Besides all this, the accounts of the caziques and grandees of Mexico, and even of Quauhtemoctzin himself, who was alive at that time, all correspond with my statement. Lastly, it is also mentioned in the books and paintings which contain the history of the country.

With respect to the extensive and splendid courtyards belonging to this temple I have said sufficient above. I cannot, however, pass by in silence a kind of small tower standing in its immediate vicinity, likewise containing idols. I should term it a temple of hell; for at one of its doors stood an open-mouthed dragon armed with huge teeth, resembling a dragon of the infernal regions, the devourer of souls. There also stood near this same door other figures resembling devils and serpents, and not far from this an altar encrusted with blood grown black, and some that had recently been spilt. In a building adjoining this we perceived a quantity of dishes and basins, of various shapes. These were filled with water and served to cook the flesh in of the unfortunate beings who had been sacrificed; which flesh was eaten by the papas. Near to the altar were lying several daggers, and wooden blocks similar to those used by our butchers for hacking meat on. At a pretty good distance from this house of horrors were piles of wood, and a large reservoir of water, which was filled and emptied at stated times, and received its supply through pipes underground from the aqueduct of Chapultepec. I could find no better name for this dwelling than the house of satan!

I will now introduce my reader into another temple, in which the grandees of Mexico were buried. The doors of which were of a different form, and the idols were of a totally different nature, but the blood and stench were the same.

Next to this temple was another in which human skulls and bones were piled up, though both apart; their numbers were endless. This place had also its appropriate idols; and in all these temples, we found priests clad in long black mantles, with hoods shaped like those worn by the Dominican friars and choristers; their ears were pierced and the hair of their head was long and stuck together with coagulated blood. Lastly, I have to mention another temple at no great distance from this place of skulls, containing another species of idol, who were said to be the protectors of the marriage rights of the men, to whom likewise those abominable human sacrifices were made. Round about this large courtyard stood a great number of small houses in which the papas dwelt, who were appointed over the ceremonies of the idol-worship. Near to the chief temple we also saw an exceedingly large basin or pond, filled with the purest water, which was solely adapted for the worship of Huitzilopochtli and Tetzcatlipuca, being also supplied by pipes underground from the aqueduct of Chapultepec. There were also other large buildings in this neighbourhood, after the manner of cloisters, in which great numbers of the young women of Mexico lived secluded, like nuns, until they were married. These had also two appropriate idols in the shape of females, who protected the marriage rights of the women, and to whom they prayed and sacrificed in order to obtain from them good husbands.

Although this temple on the Tlatelulco, of which I have given such a lengthened description, was the largest in Mexico, yet it was by no means the only one; for there were numbers of other splendid temples in this city, all of which I am unable to describe. I have to remark, however, that the chief temple at Cholulla was higher than that of Mexico, and was ascended by 120 steps: also the idol at Cholulla stood in greater repute; for pilgrimages were made to it from all parts of New Spain, to obtain forgiveness of sins. The architecture of this building was also different, but with respect to the yards and double walls they were alike. The temple of the town of Tetzcuco was also of considerable height, being ascended by 117 steps, and had broad and beautiful courtyards, equal to those of the two last mentioned, but differently constructed. It seems indeed quite laughable that each province and every town should have its own peculiar idols, which, however, never interfered with each other, and the inhabitants severally sacrificed to them.

Cortes, and the whole of us at last grew tired at the sight of so many idols and implements used for these sacrifices, and we returned to our quarters accompanied by a great number of chief personages and caziques, whom Motecusuma had sent for that purpose.

While discussing books that have influenced me, I noted that this real history is less like textbook history and more like a swords-and-sorcery novel: evil priests, hair matted with blood, commit human sacrifices atop pyramids amidst a city built on a lake inside a volcanic crater; frenzied fighting ensues.

The Aztecs’ floating gardens, or chinampas, are fascinating, but it’s hard to ignore stories of conquistadors sacrificed and eaten.

Bernal Diaz Del Castillo mentions smallpox specifically five separate times, but the main germs portion of the Guns, Germs, and Steel might have been salmonella.

One last thing, the iconic Spanish conquistador helmet wasn’t worn by Cortez or Pizarro. The morion helmet came later.

The test yielded 26 male-female comparisons

February 17th, 2020

Human Diversity by Charles MurrayCharles Murray continues to explain sex differences in cognitive skills (in Human Diversity: The Biology of Gender, Race, and Class):

The most famous cognitive measure is the IQ test. The tests are designed to minimize sex differences, but minor sex differences in test scores do exist, and they have usually, though not always, favored males.

[...]

Girls outscored boys in reading in every single PISA country, with effect sizes that ranged from a low of +0.08 in Peru to a remarkable high of +0.83 in Jordan.

[...]

“Sex differences in mental rotation and line angle judgment performance were universally present across nations, with men’s mean scores always exceeding women’s mean scores.”

[...]

In all, the test yielded 26 male-female comparisons. Twelve of them amounted to an absolute effect size of less than 0.1. Women outscored men on six of the seven measures of accuracy with an effect size greater than 0.1, and they outscored men on four of the seven measures of speed with an effect size greater than 0.1.

  • Females had more accurate memory for items involving words and people.
  • On IQ-like items, women did better on the verbal ones; men did better on the spatial ones.
  • On the three subtests measuring social cognition, females were both more accurate and faster than males on all of them.
  • On the subtest measuring motor speed, males were faster than females.

What percentage of murder arrestees in New York City are young minority males?

February 17th, 2020

Benjamin Dixon, host of “the dopest political podcast in the game,” recently shared audio of Mike Bloomberg’s 2015 Aspen Institute speech, where he says, “Ninety-five percent of your murders — murderers and murdered victims — fit one MO. You can just take the description, xerox it and pass it out to all the cops. They are male, minorities, sixteen to twenty-five. That’s true in New York; that’s true in virtually every city.”

This is, of course, terribly racist.

That ninety-five percent figure is ludicrously high. What’s the real number? Let’s look at Police Commissioner Dermot F. Shea’s 2019 report on Crime and Enforcement Activity in New York City:

Murder and Non-Negligent Manslaughter in NYC by Race

So, ninety-seven percent of suspects and arrestees are minorities, not ninety-five. We don’t have numbers for age and sex though.

Even when men do well in social cognition tasks, they are not using the cognitive tools most naturally suited to that purpose

February 16th, 2020

Human Diversity by Charles MurrayOn average males have substantially better visuospatial skills than females — as evidenced by the Piaget water-level test and the bicycle-drawing test — while women have better social cognition. Bright men can compensate, as Charles Murray explains (in Human Diversity: The Biology of Gender, Race, and Class, based on Diane Halpern’s Sex Differences in Cognitive Abilities):

Males are rarely good at both systemizing and empathizing. In contrast, these skill sets are largely independent in women.

[...]

The same study found evidence that men apply systemizing skills to empathizing tasks. Put another way, even when men do well in social cognition tasks, they are not using the cognitive tools most naturally suited to that purpose.

Your two best strategies are to be really healthy and really rich

February 16th, 2020

If you hope to live a long time, Alex Hutchinson (Endure) reminds us, your two best strategies are to be really healthy and really rich:

That’s the conventional wisdom and the statistics seem to back it up. But a surprising new study that links the longevity of Olympic athletes to their socioeconomic status offers a more nuanced picture of why elite athletes tend to outlive the rest of us. It’s not just about muscles and money — it’s also about the stress of competition, not only in sport, but in life.

Adriaan Kalwij, an economist at Utrecht University in the Netherlands, combed through the records of every Dutch athlete who competed in the Summer and Winter Games between 1896 and 1964, excluding more recent years because most of those athletes are still alive. Using their birth dates, death dates and stated occupation, he was able to explore how socioeconomic status (SES) influenced their longevity.

The results, published in PLOS One in December, confirmed that the 934 Olympians outlived their age-matched Dutch peers by a few years, as other studies of elite athletes have previously found. They also found that the influence of SES has steadily increased over the past century.

In the oldest cohort of athletes, born between 1852 and 1899, SES had no significant effect on longevity. In a sense, Kalwij says, this is what you might expect of Olympians: “excellent innate health could make them ‘immune’ to a SES-lifespan gradient.”

But in the next cohort of athletes, born between 1900 and 1919, a gradient emerges. Those classed as low SES, such as unskilled labourers, lived on average five years less than medium (teachers, office workers) and high (lawyers, doctors) SES athletes.

And in the most recent cohort, born between 1920 and 1947, an even wider gap emerges: High SES athletes lived five years longer than medium SES athletes, who in turn lived six years longer than low SES athletes — a stunning difference of 11 years between the top and bottom group, despite their healthy youth.

What’s most surprising about this trend is that it’s going the wrong way. You’d expect that the strengthening of social programs such as universal health care and state pensions over the past half-century would have reduced the health penalty incurred by poverty. Instead, Kalwij’s results join a large body of data across numerous countries, including Canada, suggesting that the influence of social class on lifespan has been growing since the 1950s.

While there are numerous factors that could contribute to an SES-health gradient, including access to health care and behaviours such as smoking and drinking, Kalwij believes that psychological stress may play a role.

I think we need to keep in mind that socio-economic status changed dramatically over the 20th Century, from inherited wealth and titles to inherited traits.

Adam Savage harnesses Spot to a dog-cart

February 15th, 2020

Adam Savage wanted to use Spot, from Boston Dynamics, to take him on a trip, so he created what he called a robot rickshaw — but which I’d call a robot dog-cart:

You don’t want your first exposure to be on the street

February 15th, 2020

In New Jersey recently a shoplifter pepper-sprayed two store security guards who confronted her after she stole some merchandise. Greg Ellifritz has been exposed to pepper spray over 50 times in training and on the street and offers his advice:

I think the first step to consider is retreating. Most small cans of chemical irritant have a very limited range. The small keychain type sprays only shoot about five feet. The larger canisters that cops carry shoot a stream that is 10-15 feet. Excepting the large fire extinguisher-style cans, you would be out of range of any commonly carried chemical spray if you could get at least 20 feet away.

If escape isn’t an option, shielding can work. If the spray doesn’t get in your eyes, you will likely still be able to function at almost full capacity. You might cough a bit, but you won’t be disabled. Cover your eyes with a hand. Alternately you can go into a “horizontal elbow shield” position and tuck your face inside the crook of your elbow for protection. Even holding something like a briefcase or notepad over your face will stop the majority of the spray from getting into your eyes.

If you can’t escape or shield, recognize that you are going to be sprayed. Know in advance how you will react. You can usually continue fighting, but some people panic when they are hit with the spray for the first time. Their panic leads to a freezing response that makes them unlikely to be able to defend themselves. The spray painful. It makes you cough and your eyes burn. But most of you can fight through the pain as long as you know what to expect.

You don’t want your first exposure to be on the street while you are fighting a criminal. It would be a great idea if you had someone spray you in a controlled situation first so that you aren’t shocked by the effects when you have to fight it on the street. If you don’t want to take a full spray to the face, spray some OC onto a gauze pad and wipe the corner of your eye with it. You’ll get a good taste of what the spray feels like and still be able to decontaminate relatively quickly.

97 males and 7 females got perfect scores

February 14th, 2020

Human Diversity by Charles MurrayAverage men and women have similar verbal and math abilities Charles Murray notes (in Human Diversity: The Biology of Gender, Race, and Class, leaning on Diane Halpern’s Sex Differences in Cognitive Abilities), but not as similar at the extremes:

On tests with nationally representative samples, females can be expected to consistently outperform males on a variety of verbal tasks, with a small advantage in reading and a more substantial advantage in writing.

[...]

To the question, “Is the typical male better at math than the typical female?” the answer is close to settled: “If yes, not enough to be noticeable,” with an open possibility that a small gap will close altogether.

[...]

“Sex differences in mathematics become progressively larger as the sample becomes more selective and the type of math skill becomes more advanced,” writes Halpern, and herein lies a major issue in the study of cognitive sex differences.

[...]

The last 60 years have seen major reductions in the male advantage at the extreme high end for 7th graders. For those in the top two percentiles, a ratio of about 2.0 in 1960 appears to have disappeared. For those in the top percentile, a male ratio of about 7.0 has fallen to around 1.5. At the most stratospheric level, the top 1 percent of the top 1 percent, a male advantage that was measured at about 13 to 1 in the 1970s and the early 1980s has fallen to less than 3 to 1.

[...]

In short, what was once thought to be an overwhelming male advantage at high levels of math achievement has been greatly reduced during the last six decades.

[...]

The male-female ratios in the top percentiles of the AMC12 are substantial and they grow larger at the 98th and especially the 99th percentile. In the table, I counted perfect scores of 150 as being in the 99th percentile. When they are broken out separately, it turns out that from 2009 to 2018, 97 males and 7 females got perfect scores: a ratio of 13.9.

A mix of neural networks and depth-aware video frame interpolation

February 14th, 2020

YouTuber Denis Shiryaev took the Lumière Brothers’ 1896 short clip “Arrival of a Train at La Ciotat” — digitized at 640-by-480 resolution, and 20 frames per second — ran it through some neural networks, and upscaled it to 4K resolution, at 60 fps:

As you can see, it’s not exactly impressive by today’s standards, so Denis used a mix of neural networks from Gigapixel AI and a technique called depth-aware video frame interpolation to not only upscale the resolution of the video, but also increase its frame rate to something that looks a lot smoother to the human eye.

Memory comes in many forms

February 13th, 2020

Memory comes in many forms — long-term and short-term, “autobiographical,” “episodic,” and “semantic,” among others — Charles Murray notes (in Human Diversity: The Biology of Gender, Race, and Class), and females have an advantage in some of them (as Diane Halpern notes in Sex Differences in Cognitive Abilities):

  • Females tend to be better than males at remembering faces and names.
  • Females tend to be better than males at recognizing facial emotions.
  • Females tend to be better at remembering the minutiae of an event (labeled peripheral detail), while males tend to be better at remembering the core events (labeled gist).
  • Females tend to remember speech they have heard better than males, particularly when it relates to emotionally laden events in their past.
  • Females tend to retain memories from earlier childhood better than males do.
  • Females tend to have better short-term memory than males (e.g., given a list of single-digit numbers, they remember longer lists than males do).
  • Females tend to have better verbal working memory (e.g., remembering a list of numbers while answering questions about an unrelated topic).
  • Females tend to have better memory for locations of objects (e.g., remembering where the car keys were left).
  • Males tend to have better visuospatial memory (e.g., navigating on the basis of a combination of landscape features).

Hydrogen is a bad car fuel, but maybe a decent boat fuel?

February 13th, 2020

Hydrogen is a bad car fuel, Toyota has learned from the Mirai hydrogen experiment, but it may make a decent boat fuel, as it hopes to demonstrate with its Energy Observer, a former racing catamaran with some new additions:

The Energy Observer uses a pair of wind turbines and a vast array of solar photo-voltaic cells to both propel the vessel and provide power to its on-board hydrogen-creating electrolysis process. Sea water is essentially zapped into its component parts and the isolated hydrogen is captured to be expended inside the Toyota fuel cell generator. The process emits nothing but oxygen and water out the “tailpipe”.

Toyota Energy Observer

In optimum conditions, the boat is propelled entirely by wind and solar. A rack of lithium cells onboard keep the thing running when it’s cloudy or calm winds, and Toyota’s fuel cell system takes over to produce the boat’s propelling energy at night.

I’m thinking it might be a better airship fuel.