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The Holy Algorithm

As it will surely not have escaped your insight, this weekend is Easter. Why now? The date of Easter is determined by a complicated process called the Computus Ecclesiasticus. I will just quote the Wikipedia page:

The Easter cycle groups days into lunar months, which are either 29 or 30 days long. There is an exception. The month ending in March normally has thirty days, but if 29 February of a leap year falls within it, it contains 31. As these groups are based on the lunar cycle, over the long term the average month in the lunar calendar is a very good approximation of the synodic month, which is 29.53059 days long. There are 12 synodic months in a lunar year, totaling either 354 or 355 days. The lunar year is about 11 days shorter than the calendar year, which is either 365 or 366 days long. These days by which the solar year exceeds the lunar year are called epacts. It is necessary to add them to the day of the solar year to obtain the correct day in the lunar year. Whenever the epact reaches or exceeds 30, an extra intercalary month (or embolismic month) of 30 days must be inserted into the lunar calendar: then 30 must be subtracted from the epact.

If your thirst of knowledge is not satisfied, here is a 140-page document in Latin with more detail.

As far as I understand, during the Roman Era the Pope or one of his bureaucrats would perform the computus, then communicate the date to the rest of Christianity and everybody could eat their chocolates at the same time. Then, the Middle-Ages happened and communication became much harder, so instead they came up with a formula so people could compute the date of Easter locally. Of course, the initial formulas had problems – with the date of Easter dangerously drifting later and later in the year over centuries, and don’t even get me started on calendar changes. Eventually Carl Friedrich Gauss entered the game and saved humanity once again with a computationally-efficient algorithm (I am over-simplifying the story so you have more time to eat chocolate).

But now is 2021, and I’m wondering how they run the algorithm now, in practice. I looked up “how is the date of Easter calculated” but all the results are about the algorithms themselves, not about their practical implementation. I have a few hypotheses:

  1. There are responsible Christians everywhere who own printed tables with the dates of Easter already computed for the next few generations. If your Internet goes down, you can probably access such tables at the local church.
https://upload.wikimedia.org/wikipedia/commons/e/e4/DiagrammePaques_Flammarion.jpg
Here is such table from 1907 (Wikimedia commons)

Of course this does not really solve the problem: who comes up with these tables in the first place? Who will make new ones when they expire?

2. There is a ceremony in Vatican where a Latin speaker ceremoniously performs the Holy Algorithm by hand, outputs the date of Easter, prints “Amen” for good measure and then messengers spread the result to all of Christianity.

3. Responsible Christians everywhere own a Computus Clock, a physical device that tells you if it is Easter or not. When in doubt, you just pay a visit to that-guy-with-the-computus-clock. Then, it is like hypothesis 1 except it never expires.

4. There is software company (let’s call it Vatican Microsystems®) who managed to persuade the Pope to buy a license for their professional software solution, Computus Pro™ Enterprise Edition 2007 – including 24/7 hotline assistance, that only runs on Windows XP and they have a dedicated computer in Vatican that is used once in a while to run these 30000 lines of hard Haskell or something. Then, it goes just like hypothesis 2.

(Of course, all of these solutions are vulnerable to hacking. It might be as easy as sneaking into a church and replace their Easter tables with a fake. A talented hacker might even have it coincide with April fools.)

If an active member of the Christian community reads this and knows how it is done in practice, I am all ears.

Anyways, happy Easter and Amen, I guess.

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90% true: Broken news

This post is only 90% true. Among these ten items, one was deliberately made-up. Each items includes links to sources, so you can easily check if they are true. Can you find the fake item? (More information about the series here.)

Answer for the previous episode, “Agriculture from the future”: #5 was false.

1. The mainstream media is clearly biased against your political group. At least, that’s what you think. This called the “hostile media effect” – people from both sides of any issue consistently believe that the media is biased against their side. And the more involved they are, the stronger the effect.

2. Is it possible to measure the political bias of a journal objectively? Researchers at Stanford and Cornell came up with a clever solution: they compared the full transcript of politicians’ speeches to the parts that were quoted in the media. As it turns out, different journals will put the emphasis on different parts of the speech. This allowed the researchers to make a map of many media outlets based on their bias. They also have a fascinating interactive tool where you can look at Barack Obama’s speeches and color the different phrases according to the political leaning of journals that cited them – right-wing media in red, left-wing media in blue. Color-coded Obama speech

3. Another approach to quantify media bias is simply to ask journalists who they vote for, and compare them to the rest of the population. To put it simply, journalists tend to be considerably more left-wing than the average person. According to a series of large surveys of American journalists spanning several decades, the share of Republicans shrunk from 25% in the 1970s to 7% in 2013 – making them outnumbered 4 times by Democrats. Other recent analyses found similar results.

4. Over the last thirty years, the media has become measurably more subjective and emotional. A large lexical analysis of media from the USA found that journalists report less and less about facts and context, and more and more about emotions and advocacy. But, to their defense, it’s not just journalists. Speeches of politicians themselves become less analytic and more clout-based. This did not start with Donald Trump – it has been happening gradually since 1900.

5. Terrorist attacks receive unequal coverage from the media. An analysis of 136 terror attacks in the USA found that the number of victims, the nature of the target and whether the perpetrator was arrested all influence the coverage. But the most important predictor was the religion of the perpetrator: if it was done by a Muslim, it received 357% more media coverage.

6. Speaking of terrorism, there is evidence that abundant coverage of mass shootings by the media causes future mass shootings in the following days. To detect causality, this study used natural disasters as an instrument. If a natural disaster happens around the same time as a mass shooting, the later receives less coverage – and we can see there are fewer mass shootings in the next few days.

7. Criminals tend to receive longer sentences when television talks a lot about criminal events. This effect is not due to the overall amount of crime, but specifically to media exposure.

8. Native advertising is the practice of including advertisement that blends in the native style of the journal. This is not only used by companies to insidiously praise their products, but also by authoritarian governments from other countries to publish their political propaganda. China Daily, an English-language publication controlled by the Chinese Communist Party, has paid millions to American journals such as the Washington Post, the Wall Street Journal or the New York Times to publish propaganda disguised as regular articles1Native advertising is usually disclosed with a little label, like “sponsored content”..

9. The protozoan Toxoplasma gondii, which infects about one third of the population in asymptomatic form, is known to alter behavior and increase impulsivity and aggression. A 2018 study from University of Colorado found that students who tested positive for Toxoplasma were 1.4 times more likely to major in journalism. In addition, they were 1.7 times more likely to select courses specifically on political journalism.

10. Does the political bias of the news you read affect what you think in a causal way? Researchers offered free subscriptions to either the left-wing Washington Post or the right-wing Washington Times, in a randomized way. They also had a control group who received no free subscription. One month later, Virginia held gubernatorial elections and the researchers asked the subjects of the experiment who they voted for. Those who received the Post were 11% more likely to vote Democrat. But those who received the Times were also 7.4% more likely to vote Democrat, compared to the group that received nothing. Apparently, reading a print journal makes you more likely to vote Democrat, regardless of the journal’s political orientation.

Could you find the false item? Feel free to discuss about it in the comment section. The answer will be given in the next episode.

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Invisible privileges

1.

Let’s review the evidence.

African-Americans are twice as likely to be stopped by the police. Police officers speak less respectfully to them. They are more likely to use violence against them. Overall, African-American men get killed by the police 2.5 times as often as White men. Then, African-Americans face discrimination at every stage of the justice system. For an identical case and history, African-American defendants have 10% higher odds of being incarcerated. When they are, they receive 10% longer sentences for the same crime.

African-Americans also face discrimination when they are the victims. Criminals receive lighter sentences when their victim is black1 However, it is not clear whether this is really due to discrimination or to other factors. In fatal traffic accidents, drivers receive a 53% shorter sentence if the person they killed happens to be black. When a black person goes missing, there is 3.1 times less media coverage than if the victim is white2This is called the Missing White Woman Syndrome. This study was conducted in 2016, before the Black Lives Matter movement gained popularity. It would be interesting to see how things have changed as a result..

Institutional discrimination also appears in the education system. Teachers systematically give better grades to students from the white majority than to ethnic minorities, for identical works3There are two kinds of methodologies to address this question. The most common is to compare the grades obtained by a student when the teacher knows her identity, with grades obtained by the same student on blind examinations. The second one is to fabricate a fake essay and ask teachers to grade it, while changing only the name of the student, and see if they are graded differently.. At school, African-American children receive harsher punishments for the same behavior as well as closer surveillance from teachers. And overall, in the US, African-Americans are 12% less likely to access higher education than white people.

Then, there is housing discrimination. When ethnic minorities apply to rent an apartment, their odds of receiving a positive response are 47% lower, everything else equal. With no surprise, African-Americans are 4.5 times as likely to be homeless, and then 45% less likely to be sheltered.

In addition, ethnic minorities generally have poorer health than white people. Black people work more dangerous jobs, making them 33% more likely than white people to be injured at work. They are 16 % more likely to die on their workplace. On average, the life of black people is 4.3 years shorter than white people’s.

Most of those results are from large studies, they are solid and have been replicated many times. Yet some people decide to completely ignore all the evidence, and still deny the existence of racist discrimination. How is it even possible? What is going on in the head of racism-deniers?

2.

Men are 2.5 times more likely than women to be stopped by the police. Police officers are more likely to arrest men and more lenient toward women. Overall, men get killed by the police 20 times more often than women. Then, men face discrimination at every stage of the justice system. Men are more likely to be considered guilty and receive harsher sentences than women for an identical case and history4These studies are called “mock juror trials”. They use a panel of jurors who are presented with a fictional case, where only the gender or ethnicity of the defendant is changed, and asked what the sentence should be. This way, everything is exactly identical except the gender of the defendant, so any difference can be attributed to discrimination. Some studies even staged fake audiences with comedians for extra realism.. Men have 1.64 to 2.15 times higher odds of being incarcerated, depending on the study. When they are, men also receive 30% to 63% longer sentences for the same crime compared to women5These are observational studies, meaning they look at the outcomes of a large number of real-life cases, taking into account offense severity, previous offenses, whether the defendant has to take care of children, and other confounders.. The sexist bias favoring women is much larger than the racial bias – that is, black women are treated better than white men. As you might expect, justice’s double-standard against men is especially marked for sexual offenses.

Men also face discrimination when they are the victims. Criminals receive lighter sentences when their victim is a man6With the same caveat as for racial discrimination.. In fatal traffic accidents, drivers receive a 36% shorter sentence if the person they killed happens to be a man. When a man goes missing, there is 2.9 times less media coverage than if the victim is a woman.

Institutional discrimination also appears in the education system. Teachers systematically give better grades to girls than to boys, for identical works. This happens already in elementary school, continues in middle school, and again in high school, and again in college7Interestingly, these studies found that female teachers were on average more biased in favor of girls than male teachers.. This favoritism for girls has measurable effects on boys’ progress and future career orientation. Parents also invest more time teaching girls than boys and spend 25% more money on girls’ education. At school, boys receive harsher punishments for the same behavior as well as closer surveillance from teachers. And overall, in the US, men are 16% less likely to access higher education than women. Here again, the gender gap is larger than the racial gap8Moreover, unlike for ethnic minorities, there is no affirmative action attempting to correct this disparity – even when women are more likely to access higher education, affirmative action is still in favor of women..

Then, there is housing discrimination. When women apply to rent an apartment, their odds of receiving a positive response are 28% higher than men, everything else equal. With no surprise, men are 1.5 times as likely to be homeless, and then 40% less likely to be sheltered. A study in France found that 90% of the people who die in the streets are men9It should be noted that the gender gap in homelessness is more marked in France than in the USA..

In addition, men generally have poorer health than women. Men work more dangerous jobs, making them 40% more likely than women to be injured at work. They are 8 times more likely to die on their workplace. On average, the life of men is 5 years shorter than women’s10The gap in life expectancy is commonly attributed to biological factors, as a legitimizing myth. However, this study on monks and nuns (who do pretty much the exact same things throughout their lives) found that at most one year of the gap could be attributed to biological differences.. In spite of this, there is much more scientific research and US national offices dedicated to women’s health. Medical research on women’s health receives considerably more funding than men’s health, even for conditions that affect men more often11See the tables from page 56. For lung cancer, in 2016 the NIH spent $180,000,000 for women-specific research, $318,000 (!) for men-specific research, and $136,000,000 for lung cancer in general. They also spent $1,916,000 for women’s suicides, and only $156,000 for men’s suicides, despite men dying from suicide about four times as often..

Like for racism, most of those results are from large studies, they are solid and have been replicated many times. Yet some people decide to completely ignore all the evidence, and still deny the existence of discrimination privileging women. Just like racism, discrimination against men has been systematically made invisible.

3.

I am aware that many readers will hear about discrimination against men for the first time. Perhaps you’ve heard about discrimination from the police beforehand, but did you know about the grading discrimination? Did you know about the housing discrimination? If not, why didn’t anybody tell you about it?

One thing to consider is that people can’t really tell how much discrimination they face based on their subjective experience. In their classic 1997 book Social Dominance, social psychologists Jim Sidanius and Felicia Pratto report that (in 1997) many African-Americans had no clue about how much racism they faced12See page 106 of the book.. In the 1990s, 58% of African-Americans believed they had the same housing opportunities as white people. 46% thought they had the same chances at employment, and 63% thought they had the same chances in education – despite clear evidence of the contrary13Sidanius and Pratto dedicate the third part of their book to evidence of discrimination against black people. However, they completely disregard discrimination against men – to be fair, most of the evidence that I discussed here was published after the book Social Dominance came out, so you can’t blame the authors.. This is one of the universal patterns described in Social Dominance: unfair treatment against subordinate groups is overlooked, legitimized, and actively erased by the dominant status quo, until even the discriminated population believes it is not real. It is perfectly possible to face discrimination on a daily basis and be completely unaware of it.

In addition, there is growing evidence that people (academics, the media, people in general) care very little about the issues that affect men. Most people know about manspreading, but have never heard about the teacher grading gap. People think gender balance at work is important, but only in professions where women are underrepresented. Scientific studies that find a bias against women are cited far more often than studies that find a bias against men, even when the later use larger samples. Remember the kidnapping study I mentioned above, which found that there is less media coverage when a man goes missing? This is the same process. Presumably, this attention disparity is the result of traditional gender roles, which (among many other things) say that men are not expected to complain, and will be shamed if they do so – but this is a complicated topic that deserves a future blog post on its own.

As a takeaway, there is a striking similarity between discrimination against ethnic minorities and discrimination against men. My point is not to say that minorities or men “have it harder”, nor is it that racism is exactly identical to sexism – the historical and social mechanisms are obviously entirely different. My point is that, currently, men and ethnic minorities experience a similar pattern of stereotyping and discrimination in their daily life. The strange polarization of the culture wars makes it even harder to notice: the political tribes who care about racism are sharply separated from the tribes who care about men’s issues. This is unfortunate, because both tribes share the common goal of eliminating discrimination14Of course, there are also traditionalists who just use men’s issues as an excuse to attack feminism, hoping to restore traditional gender roles. I personally believe, on the contrary, that traditional gender roles are the cause for discrimination, and that we need to step away from them. – maybe their filter bubbles only show them one side of the problem? It took decades for the majority of the population to realize that racist discrimination is real. For sexism against men, such a shift in collective consciousness has yet to happen.

If you spot any mistake or inaccuracy in this text or the supporting evidence, please let me know in the comments, so I can correct it.

Annex: what about hiring discrimination?

Hiring discrimination can be measured by sending fictional resumes to employers, only changing the ethnicity or gender of the applicant, and counting how many replies you get. As you expect, equally-qualified ethnic minorities are far less likely to be hired. Regarding gender discrimination, the evidence is much more mixed. This makes it very easy to cherry-pick studies that show discrimination against women (if you read feminist sources) or against men (if you read MRA sources). This meta-analysis found moderate discrimination against men, but only in female-dominated jobs. This systematic review lists 11 studies looking at pure gender discrimination (man vs woman). Two of them found discrimination against women, four of them found discrimination against men, and the rest found no discrimination. A recent study which tracked recruiters’ behavior on online hiring markets found that women face a 6.7% penalty in men-dominated occupations, and that men face a 12.6% penalty in women-dominated occupations. Overall, gender discrimination in hiring is much less systematic than racial discrimination. This discrepancy is probably a remnant of the traditional gender division of labor, since men were traditionally assigned to salaried jobs. In any case, the common claim that it is harder for women to find employment appears to be wrong.

Changelog:

30-11-2020 – According Leeth et al., 2005, the racial gaps in fatal and non-fatal workplace injuries are respectively 16% and 33%, not 20% as previously reported.

01-02-2021 – A few studies on the effect of victim gender/origins on sentencing found no evidence for discrimination after controlling for case details. Thanks Greg for pointing that out. I also moved hiring discrimination to an annex, and added the recent study by Hangartner et al.

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90% true: Agriculture from the Future

This post is only 90% true. Among these ten items, one was deliberately made-up. Each items includes links to sources, so you can easily check if they are true. Can you find the fake item? (More information about the series here.)

  1. Insect-resistant, genetically-modified maize have been cultivated in Spain and Portugal for more than twenty years. A 2019 study analyzed the environmental effects: aside from the obvious decrease in pesticide pollution and water savings, there was a measurable drop in greenhouse-gas emissions. This is because diesel-powered tractors were no longer needed to spray the insecticides. The downside of insect-resistant GMOs is that new pests will eventually emerge after a few decades, just like they do with chemical pesticides. Biotechnology could also have an impact on climate change in a more direct manner – for example, engineering the gut microbiota of cows to minimize the production of methane by cattle, or genetically modifying poplars for wood production so they no longer release isoprene, a pollutant that increases the air concentration of ozone and methane.
  2. You might think that millions of years of evolution would have fully optimized photosynthesis, but it is not quite the case. Many crops are much less efficient than what would be possible in theory. Multiple genetic strategies are possible to increase the yield of crops, for example to increase their carbohydrate production. In soybeans, rice and wheat, the process of photorespiration diverts part of the energy obtained from photosynthesis. Using tobacco plants as a model, researchers were able to increase biomass by more than 20% in field trials, just by optimizing the expression levels of various photosynthetic components.
  3. Improving the nutritional qualities of crops through genetic modification is also promising, especially in third-world countries were malnutrition is rampant. The “golden rice”, a variant of rice with a high level of vitamin A was developed more than fifteen years ago. So far, it has not been widely adopted (in part due to efforts from Greenpeace to undermine it). More recently, by enhancing cassava with an iron transporter and the iron-storage protein ferritin, it was possible to increase the plant’s iron and zinc content by about ten-fold.
  4. Even without genetic modification, the fruits and vegetables we eat are very different from what is found in nature, owing to centuries of breeding. This is visible in still-life paintings from the Renaissance where fruits are on display. If you are wondering what vegetables looked like in their natural, not-genetically-modified forms, here are pictures of wild-type bananas, wild-type corn, and wild-type carrots1This last links points to a website called World Carrot Museum, with the tagline “discover the power of carrots”. That might not be an academic source, but I am sure we can trust them for all our carrot questions..
  5. Since humans started agriculture thousands of years ago, the selection of plants by breeding has completely changed our food habits. This, in turn, put an evolutionary selection pressure on humans themselves. The textbook example is lactase persistence, when the domestication of cows gave a great advantage to humans who could digest cow milk. Now, according to some research, modern humans have evolved some kind of dependency to selected plants. That is, if all the domesticated plants were to suddenly go back to their wild state, most humans would have trouble finding food they can digest.
  6. Starting in the 1950s, exposing crops to radiation became a popular way to generate new mutant varieties. The typical “gamma garden” design involves a circular field with a Cobalt-60 gamma ray source in the middle. This way, seeds are exposed to a gradient of radioactivity – the plants near the center usually die, the peripheral plants are unaltered, and interesting things can happen in the intermediate range. Needless to say, gamma rays produce mutations all over the genome, and large chromosomal rearrangements are frequently observed. Despite being much messier than genetic modification techniques like CRISPR, plants obtained through “atomic gardening” are not legally considered GMOs. They may even be accepted in organic food.
  7. There are no Terminator seeds. The legend goes that some greedy GMO company sold seeds that would turn sterile after the first generation, so that farmers could not sow them and would have to buy it again from the company every year. The underlying technology does exist, but it was never used in any commercialized product. That being said, farmers buying new seeds every year is nothing new (and not restricted to GMOs): for decades they have relied on hybrids from inbred plants, which have desirable properties but can be sowed only once since their offspring would be too heterogeneous.
  8. Local production has become an important criterion for consumers. Somehow, people are starting to realize there might be something wrong about shipping fruits and vegetables from the other side of the planet. In general, the more local, the greener. But there is a loophole: not all places are equally fertile. According to a study from 2020, only one third of the world population could sustainably feed on food produced in a radius of 100 km. In some cases, outsourcing food production to more fertile grounds could allow to spare land (i.e. growing forests), which is a good way to sequester GHG. In fact, a recent paper advocated for combining high-yield farming in some spots with land-sparing in other spots, as the optimal strategy for environment-friendly agriculture.
  9. According to large surveys of representative samples in the USA, France and Germany, extreme opponents of genetically modified foods know the least but think they know the most (this is one of the best titles for a scientific article).
  10. Like cellphones, micro-wave ovens and every other new technology, GMOs have been accused of causing cancer2For some reason, it’s always cancer. I have never met anybody who feared GMOs would cause pica or Capgras syndrome, although that would be pretty funny.. And technically speaking, yes, they do – but just as much as regular food. Carcinogenic substances can be found in small amounts in all kinds of food, e.g. in red meat, cereals, apple juice3In most cases, the amount is negligibly small. The only association that I would take seriously is red meat.… In fact, it is even possible to engineer plants so that they protect against cancer, like this broccoli.

Could you find the false item? If you have doubts, feel free to discuss about it in the comment section.