Monthly Archives: May 2010

Why Schools Test Often

The latest Science:

We modified the dictator game … and studied how inequality acceptance develops in adolescence. We found that as children enter adolescence, they increasingly view inequalities reflecting differences in individual achievements, but not luck, as fair, whereas efficiency considerations mainly play a role in late adolescence. …

We assumed that there were three salient fairness views in this situation: strict egalitarianism, finding all inequalities unfair; meritocratism, justifying inequalities reflecting differences in production; and libertarianism, justifying all inequalities in earnings. … The large majority of 5th graders were strict egalitarians, and, remarkably, there were almost no meritocrats at this grade level. In contrast, meritocratism was the dominant position in late adolescence, and the share of strict egalitarians fell dramatically. The share of libertarians was stable across grade levels. … From 9th grade, … efficiency considerations played a more important role for males than females. (more)

This seems support for my view that frequent school scoring serves the function of making kids accept dominance and inequality:

At school, our kids are rated and ranked far more often than most adults will tolerate, even though this actually slows their learning! It seems that modern schools function in part to help humans overcome their (genetically and culturally) inherited aversions to hierarchy and dominance. Modern workplaces require workers who are far more accepting than are foragers of being told what to do when, and of being explicitly ranked, and our schools prepare kids to accept this more primate-like environment. (more)

The evidence strongly suggests that students learn better when they are not graded and certainly not when they are graded on a curve. (more)

Subjects worked on different tasks and received performance-contingent payments that varied in amount from small to very large relative to their typical levels of pay. With some important exceptions, very high reward levels had a detrimental effect on performance. (more)

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Limits To Art

Bryan Caplan:

Robin Hanson has repeatedly told me that during the next million years, we’ll discover all useful science/technology; there’s only so much to know, and by then, we’ll have it all figured out. But would Robin see art the same way? By his logic, it seems like you could also say say: During the next million years, will we discover all interesting art; there’s only so much art to create, and by then we’ll have created it.

You might object, “Science is about truth, art is about creativity, so science but not art has finite limits.” But is “useful” more like “true” or “interesting”? So even given constant science, we might endlessly create novel applications. Once you go down this route, though, it’s hard to see why scientific questions – as opposed to answers – would be any less open-ended than artistic visions.

My claim is that within a million years economic growth due to innovation will have essentially ceased, at least relative to our innovation rates, in terms of giving value to creatures like us. I do not say our descendants will never discover anything new and valuable; the space of possible combinations is far too vast for that. Instead, I say new discoveries will have very close value substitutes in billions of previous discoveries. At least for creature like us, and setting aside the value of novelty itself, which cannot contribute much to economic growth.

So yes, our descendants will discover new stories, art, and even math theorems, rare items of high value in a vast mostly-unexplored space of low value items. But creatures like us will not gain substantially more value from these new items, compared to the last million such items. They may perceive a value of novelty in finding something new, and having been the one to find it. But they won’t get substantially more value from this than did their ancestors in finding the last million such novelties.

Yes it might be possible to create creatures who gain unboundedly increasing value from ever more rare yet actually found combinations. But we are not such creatures, nor do we have unbounded sympathy with such creatures. So the value obtained by creatures like us is bounded.

It is also hard to see why such unbounded-value creatures would naturally evolve in a competitive world; we evolved to value rare hard-to-find combinations because this signaled useful abilities. But when abilities are bounded, then so should be the value gained from signaling such abilities. And much of the value of such signals is relative; when some gain, others lose by comparison.

Of course in a million years we may not have expanded more than a million light-years from home, and so our economy will at least grow with our slowly expanding sphere of resources. But this growth rate is far below familiar growth rates, and far below feasible population growth rates.

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Nuke That Oil Well

Back on May 4:

As BP prepares to lower a four-story, 70-ton dome over the oil gusher under the Gulf of Mexico, the Russians — the world’s biggest oil producers — have some advice for their American counterparts: nuke it. Komsomoloskaya Pravda, the best-selling Russian daily, reports that in Soviet times such leaks were plugged with controlled nuclear blasts underground. …

The Soviet Union, a major oil exporter, used this method five times to deal with petrocalamities. The first happened in Uzbekistan, on September 30, 1966 with a blast 1.5 times the strength of the Hiroshima bomb and at a depth of 1.5 kilometers. KP also notes that subterranean nuclear blasts were used as much as 169 times in the Soviet Union to accomplish fairly mundane tasks like creating underground storage spaces for gas or building canals.

These kinds of surgical strikes to shut off underground leaks, however, were carried out only five times, with the last one occuring in 1979. And there was only one misfire, near Kharkov, Ukraine, where a nuclear blast was unable to stanch a gas leak. Happily, with a track record like that, “the chances of failure in the Gulf of Mexico are 20%,” KP writes. “The Americans could certainly risk it.”

Makes sense to me. Seems a low risk of fire or of a radioactivity release of comparable harm to the oil pollution. The Christian Science Monitor agreed May 13. On May 24 it looked like we might see reason:

President Obama has stepped in and has sent a team of nuclear experts to contain the spill. The man in charge to contain the spill is Steven Chu, U.S. Energy Secretary and also the one who helped develop the first hydrogen bomb in the 50s. The five member multidisciplinary team are a creative lot involved in the first hydrogen bomb, finding ways to mine in Mars and ways to position biomedical needles. The team will work along with BP’s scientist to find a solution. Meeting at BP’s crisis centre in Houston, Chief Executive Officer Tony Hayward said after the meeting, ‘lots of nuclear physicists and all sorts of people coming up with some quite good ideas actually.’

Alas, Today’s Post:

The failure of traditional well-killing methods may also heighten the pressure on authorities to try unconventional approaches. Simmons, for example, suggests a military takeover of the whole operation, and possibly even an attempt to seal the well with an explosive device.

Allen, the national incident commander, dismissed the idea. “My view is since we don’t know the condition of that well bore or the casings, I would be cautious about putting any kind of kinetic energy on that well head,” Allen said, “because what you may do is create open communication between the reservoir and the sea floor.”

Seems caution isn’t working so well now.  [Added: And it is hard to believe the well bore or casings matter much - it is the kinds of rock/mud/etc. near the hole that matter.]  Alas, also seems Obama has decided the nuke option is politically unpalatable.   Sure BP deserves blame for the spill itself, but doesn’t anti-nuke political correctness deserve lots of blame for our reluctance to stop the spill?


One prominent energy expert known for predicting the oil price spike of 2008 says sending a small nuclear bomb down the leaking well is “probably the only thing we can do” to stop the leak. Matt Simmons, founder of energy investment bank Simmons & Company, also says that there is evidence of a second oil leak about five to seven miles from the initial leak that BP has focused on fixing. That second leak, he says, is so large that the initial one is “minor” in comparison.

Obama seems to have avoided getting involved in fixing this spill, for fear of being tarred with its failures.  May 28:

Obama … said that his administration is doing all it can, but that, when it comes to plugging the leak, “the federal government does not possess superior technology to BP.”

But I’ll bet BP doesn’t have nukes. If nukes are the answer, then leaving the fix to BP has definitely made things worse.

Added 31May:

The Russian television channel RT described how Soviet authorities used underground nuclear explosions to seal off leaking gas pipes. The idea is that the explosion shears the leak closed for good. “That’s not something we’re considering. It would be far too risky,” said BP’s MacEwen. (more)

They don’t explain what risk they have in mind.

Added 3June:  Yesterday National Review had an article favoring the nuke option. The NYT had article “Nuclear Option on Gulf Oil Spill? No Way, U.S. Says.”

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Drugs Don’t Help

In 2003, Bush had the US govt start to pay for drugs for seniors.  This induced seniors to use lots more drugs, but they were not any healthier.

We find that gaining prescription drug insurance through Medicare Part D was associated with an 63% increase in the number of annual prescriptions, but that obtaining prescription drug insurance is not significantly related to use of other health care services or health, as measured by functional status and self-reported health. Among those in poorer health, we find that gaining prescription drug insurance was associated with a 56% increase in the number of annual prescriptions, and is not significantly related to health. (more)

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School Isn’t Healthy

The schooled are healthier, but school doesn’t make folks healthy:

There is a strong, positive and well-documented correlation between education and health outcomes. … [We study] two changes to British compulsory schooling laws that generated sharp differences in educational attainment among individuals born just months apart. … The cohorts just affected by these changes completed significantly more education than slightly older cohorts subject to the old laws. However, we find little evidence that this additional education improved health outcomes or changed health behaviors. (more)

The latest AER has two empirical papers (here, here) purporting to show that school does cause health. They use fancier, but in my opinion less reliable techniques.

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Chase Your Reading

Hunting has two main modes: searching and chasing.  With searching you look for something to chase. With chasing, in contrast, you have a focus of attention that drives your actions. You may find something else worth chasing along the way, and then switch your focus to a new chase, but you’ll still maintain a focus.

It seems to me that while reading non-fiction, most folks are in searching mode. Most would be more intellectually productive, however, in chasing mode. It helps to have in mind a question, puzzle, or problem, and then read in order to answer your question, explain your puzzle, or solve your problem.

In searching mode, readers tend to be less critical. If a source came recommended, they tend to keep reading along even if they aren’t quite sure what the point is. Since authors tend to be more prestigious than readers, readers tend to feel reluctant to question or judge what they’ve read.  They are more likely to talk about whether they enjoyed the read, than whether the author’s argument works.

In chasing mode, readers are naturally more critical. When you are looking for something particular, it feels less presumptuous to stop reading when your source comes to seem irrelevant. After all, the source might be good for some other purpose, even if not for your purpose.

In chasing mode, you continually ask yourself whether what you are reading is relevant for your quest, or whether the author actually has anything new or interesting to say. You flip around seeking sections that might be more relevant, and you might even look up the references for an especially relevant section.

Also, search-readers often don’t have a good mental place to put each thing they learn. In which case they don’t end up learning much. Chasers, in contrast, always have specific mental places they are trying to fill with what they read, so they better integrate new things they learn with old things they know.

In chasing mode, readers also tend to better interleave reading and thinking. People often hope that search-mode reading will inspire them to new thoughts, and are disappointed to find that it doesn’t. Chase-mode reading, in contrast, requires constant thinking, in order to evaluate how the current source addresses your chosen focus. This tends to make it easier to notice missing holes in the literature, where your new idea can be placed.

So if you read to be intellectually productive, rather than just to fill your time, consider reading while chasing something, anything.  (From a conversation with Heather Macsorley.)

Added 8p: Katja and Andy comment, and dloye offers this quote from Samuel Johnson:

What we read with inclination makes a much stronger impression. If we read without inclination, half the mind is employed in fixing the attention; so there is but one half to be employed on what we read.

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Hail Christopher Boehm

Evolutionary psychology is a powerful set of ideas, from which I’ve drawn great insight over the last decade or so.  But like most of its fans, I didn’t realize I was missing half of the story.  You see, academic anthropology departments have long been split into two warring camps: physical vs. cultural anthropology.

Physical anthropologists include folks who dig up old skulls, and who work with animals like chimps. Cultural anthropologists focus on studying humans in diverse societies, and are more hostile to evo psych. From a review of  Evolutionary Thought in Psychology: A Brief History:

Cultural anthropology was a different story. Raw self-interest and out-group hostility played a larger role. Plotkin argues that the rise of cultural anthropology was, in no small measure, a reaction against evolutionary approaches in the social sciences. On the one hand, it was a classic turf war. Cultural anthropologists feared that an evolutionarily based social science would put them out of business, and this motivated them to drive out the evolutionary infidel. On the other hand, many leading cultural anthropologists, particularly Franz Boas and his students, who were distrustful of the theory of natural selection. They argued that cultural expressions and the science of culture had little to do with biology and that everything from human sex differences to aggression were purely cultural.

Yes, it made political sense for evo psych folks to rely more on data from physical anthro folks who approved of their work, and to neglect the data of the cultural anthro folks hostile to their work. But it doesn’t make scientific sense.

Yes, since human psychology evolved from the psychology of earlier primate ancestors, studying other primates can give us important clues about the origins of our psychology.  And yes, physical fossils like skulls give us clues to how our ancestors changed.  But cultural anthropologists have studied in great detail recent human societies that seem to have retained much of the lifestyle of our distant nomadic forager ancestors. Surely these contain powerful clues about the social environment in which human psychology evolved.

Which brings me to Christopher Boehm and his 1999 classic  Hierarchy in the Forest, a book that has greatly influenced my thinking over the last few months.  Boehm studied on both sides of the anthropology divide, working with both chimps and “primitive” humans.  He has fashioned a powerful synthesis. A few quotes:

As members of bands or tribes, humans can be quite egalitarian … Individuals who otherwise would be subordinated are clever enough to form a large and united political coalition. … Because the united subordinates are constantly putting down the more assertive alpha types in their midst, egalitarianism is in effect a bizarre type of political hierarchy: the weak combine forces to actively dominate the strong. … They must continue such domination if they are to remain autonomous and equal, and prehistorically we shall see that they appear to have done so very predictably as long as hunting bands remained mobile. … The egalitarian political lifestyle of Upper Paleolithic hunter-gatherers could have profoundly affected our evolving social nature.

The three African great apes, with whom we share this rather recent Common Ancestor, are notably hierarchical. … Starting about five thousand years ago … people were beginning to live increasingly in chiefdoms, societies with highly privileged individuals … But before twelve thousand years ago, humans basically were egalitarian.  They lived in what might be called societies of equals, with minimal political centralization and no social classes. Everyone participated in group decisions, and outside the family there were no dominators. For more than five millennia now, the human trend has been toward hierarchy rather than equality. But the past several centuries have witnessed sporadic but highly successful attempts to reverse this trend. …

Large-game hunting brings special reputational benefits. Large game is shared by the entire band, and the resulting prestige lends itself to political ascendancy.

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Question Your Law

Snaking around the outer wall of the courthouse in Mbaiki, Central African Republic, is a long line of citizens. … Most are witches, and they are facing criminal punishment for hexing their enemies or assuming the shape of animals. By some estimates, about 40 percent of the cases in the Central African court system are witchcraft prosecutions. … The penal code. … dictates a decade or more in jail and a nominal fine for engaging in witchcraft. …

The Azande attributed a staggering range of misfortunes—infected toes, collapsed granary roofs, even bad weather—to meddling by witches. … Central Africans, who demand that the law reflect the influence of witchcraft as they understand it. … Foreign human-rights groups have noticed that many of the targets of prosecution are vulnerable types (like Pygmies, or even children). …

“The problem is that in a witchcraft case, there is usually no evidence,” … trials generally ended with an admission of guilt by an accused witch in exchange for a modest sentence. … [To determine guilt,] “the judge will look at them and see if they act like witches,” Goroth said, specifying that “acting like a witch” entailed behaving “strangely” or “nervously” in court. … Every other lawyer I met not only supported [witchcraft] criminalization, but seemed to believe in the reality of shape-shifting and killing with magic spells. …

Mbaiki’s sole foreign nongovernmental organization, … acknowledged that the rights of the accused are violated regularly in witchcraft prosecutions, because the charge carries enormous pressure to confess. But they, too, supported keeping the laws on the books, for pragmatic reasons: if people thought witches could hex with impunity, mobs would simply seize the alleged offenders, bring them to a pit, and bury them alive. (more)

Alex calls this “The unenlightened economy.” You enjoying feeling smugly superior too? Because, after all, your law uses evidence right? Well consider:

  1. Most of the accused in Mbaiki confess not because they are guilty, but because the punishment of non-confessors is much higher and court errors are frequent. Many confess in your law for exactly the same reason.
  2. Their law uses “evidence,” of the judge looking into folks’ eyes, and of the fact that some community accused them. Our judges and juries often rely on similar evidence.
  3. Your law relies on “evidence” like testimony by public police and lab workers. But what about meta-evidence on the reliability of that evidence? Do you randomly test police and lab workers to see how often they lie?   Do you do randomized trials to show what lab evidence indicates? Your law shows little interest in meta-evidence.
  4. Public law in Mbaiki is justified by claiming private law would impose overly severe punishments. But is there evidence for this, or is it a just knee-jerk rationalization?  Your arguments for public law over private law in your world may be similarly weak.
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Cannibals Die Fast

I just watched the movie The Road, and then skimmed the book. The scenario is that a calamity covers the sky with ash, making things cold and dark, and basically wiping out most of the biosphere. The story is about a child born after this starts, now at least 7 (the actor who plays him was 12 when filmed). He and his dad travel south seeking warmer climes, scavenging food along the way and avoiding “bad” folks who have resorted to cannibalism.

Both the book and movie are widely celebrated for their “realism.” NYT:

“What’s moving and shocking about McCarthy’s book is that it’s so believable,” Mr. Hillcoat said. “So what we wanted is a kind of heightened realism, as opposed to the ‘Mad Max’ thing, which is all about high concept and spectacle. We’re trying to avoid the clichés of apocalypse and make this more like a natural disaster.”

In fact, regarding the author:

You know that Cormac McCarthy won the Pulitzer Prize for literature, but you may not know that he also has an interest in mathematics and science, which he engages as a research fellow at the Santa Fe Institute.

Which stupefies me. Does anyone ever actually think about post-apocalytic scenarios?  Sure it has good emotional and physical detail, but that near-real is detached from its far-unreal premises. Consider:

1. Within a year at most wild food and human food stores would be completely gone. Locals have a far better abilities to find remainders; no way years later travelers would find much the locals hadn’t found.

2. Cannibalism would be the main food source within a year, and travelers would be easy prey for locals who lie in wait. You’d have to be very desperate to even consider traveling, and then you’d avoid lighting a campfire every night like these travelers. And you wouldn’t last long.

3. Cannibalism is war, where coordination is crucial.  Yet this pair don’t seem interested in joining a larger group for self-defense, and they see many other un-teamed individuals. Foragers understand that lone folks traveling in unfamiliar territories are goners.

4. Even under ideal conditions, people living mainly on cannibalism just couldn’t last that many years. Quoting Zac Gochenour:

The typical human body has a muscle to fat ratio similar to a bear, which is about 770 calories per pound. If the average post-apocalyptic person weighs about 130 lbs and is a bit leaner than a bear (say 600 calories per pound), throw away say 20 lbs of bones and 20 lbs of inedible organs, leaves you with about 54000 calories. Assuming 1200 calories a day for survival, that’s 45 person days per human body. 1200 may be too high; I’ve read concentration camp prisoners survived for months on about 300-500 calories per day, engaged in some degree of hard labor.

I figure the biggest problem facing such a population would be lack of essential nutrients. Vitamin C, for instance. The way the eskimos (who traditionally ate a diet consisting almost entirely on meat and fish) dealt with this is by eating their meat raw and keeping the vitamin C in tact. The cannibals would have to do the same.”

Even at a rate of 100 person days per body, that would use up 1% of the population per day.  An initial population of 100 million, killed off at this rate, would have only one person left after five years. In the novel there were many corpses around that clearly hadn’t been eaten; if only half the bodies were eaten, the population would last half as long. No way a kid lives to be seven when born into a world where the main food is cannibalism.

Given how lauded and celebrated is this book, didn’t anyone else has pointed these out before? (The novel Blindness dealt with similar sort of issues, but assumed a more realistic timescale.)

Added 29 May: Henry Farrell did say in ’07:

I agree on the campness of the broiled baby, and even more so of the amputees in the cellar. The latter annoyed me, in part because my sfnal instincts made me ask practical questions- how is this kind of cannibalism sustainable – presumably you’ve got to feed your victims something if you want to keep them alive, which sort of defeats the purpose of the thing (far smarter, if you adopt the logic of the cannibals to just butcher em and smoke em).

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Underdog Fever Is Far

We inherited from our forager ancestors a strong social norm of coordinating to resist dominance. But we follow this norm more in far mode than in near. Other folks far away, they should indignantly rebel and overthrow their oppressors, but we here must be careful and not oversimplify things.  For example, voters in other districts should throw out their corrupt politicians, but thankfully we can trust our politicians.

Also, when have little personally at stake, we support underdogs in sports, politics, and business. We overestimate their chances, and think them relatively hard-working, likable, virtuous, and beautiful. A sports team who is likely to win but gets paid less, however, is the underdog – dominance is more about overall gains than wins. But if we think a contest is close or important, such as if a business is close to home or if lives are on the line, we prefer overdogs. Details:

Two teams, A and B, were meeting in a best-of-seven playoff series for some unidentified sport, and Team A was “highly favored” to win. Which team would the students root for? Eighty-one percent chose the underdog. Then the students were asked to imagine that Team B had somehow managed to win the first three games of the series. … Half of those who first picked the underdog now said they’d support Team A. …

[Researchers] invited students to read a fake newspaper article about an upcoming rugby match. According to the article, odds makers had given one of the teams just a 30 percent chance of victory. When asked to make their own predictions, the students were more optimistic. Instead of pegging the underdog’s odds at 30 percent, they guessed it was more like 41 percent. If the article specifically referred to the disadvantaged team as an “underdog,” the effect was even stronger, with the students pegging the chance of victory at 44 percent. .. Replacing the rugby teams with mayoral candidates and then a pair of businesses competing for a contract, … the results were the same. …

Our love for the little guy is as much a judgment of character as an emotional investment. … Two-thirds of all voters in the 2004 presidential election described their preferred candidate as the “underdog.” … Presidential candidates were deemed more likable after being characterized as an “underdog”. … Being cast as the underdog can make your actions seem more virtuous and your face appear more beautiful. …

One side was described as the 9-to-1 favorite, having won each of 15 previous playoff matches. After viewing footage … the underdogs were characterized as having less “talent” and “intelligence” than the favorites but more “hustle” and “heart.” That was true even when subjects viewed the same video clip with the labels reversed. … In fact, recent data suggest that the underdogs might be dogging it. …

Two teams, A and B, are about to play an important match, for which Team A was the odds-on (7-to-3) favorite. … The students were to imagine that the players on Team A had lower salaries than the ones on Team B—their payrolls were $35 million and $100 million, respectively. … Two-thirds supported the favorite, Team A. … This was evidence that inequity aversion drives the underdog effect, “above and beyond” emotional self interest. …

A pair of companies were vying for a contract to test the drinking water in far-off Boise, Idaho. One was a large, well-established firm founded 30 years ago; the other was an eager startup. … People were inclined toward the underdog. But … if the subjects were told that the water in question might contain “cancer-causing mercury,” the underdog effect disappeared. And if the site of the water testing was changed from “Boise, Idaho” to somewhere in their own community, … subjects started rooting against the underdog.

Our affinity for the lesser team “is a mile wide and an inch deep. … We may feel morally good about rooting for the underdog, but our positive reaction is quite malleable.” … Perhaps that’s why the underdog seems most at home in the trivial world of team sports. With nothing much at stake, we’re free to indulge an idle preference for an upset. “At an unconscious level, we know we don’t take underdogs all that seriously.”

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