Secrets of the Colosseum

Beste and his colleagues spent four years using measuring tapes, plumb lines, spirit levels and generous quantities of paper and pencils to produce technical drawings of the entire hypogeum. “Today we’d probably use a laser scanner for this work, but if we did, we’d miss the fuller understanding that old-fashioned draftsmanship with pencil and paper gives you,” Beste says. “When you do this slow, stubborn drawing, you’re so focused that what you see goes deep into the brain. Gradually, as you work, the image of how things were takes shape in your subconscious.”

What Data Can’t Do

Once a useful number becomes a measure of success, it ceases to be a useful number. This is known as Goodhart’s law, and it reminds us that the human world can move once you start to measure it.

We might be interested in whether our children are getting a good education, but it’s very hard to pin down exactly what we mean by “good.” Instead, we tend to ask a related and easier question: How well do students perform when examined on some corpus of fact? And so we get the much lamented “teach to the test” syndrome. 

Textile factories were required to produce quantities of fabric that were specified by length, and so looms were adjusted to make long, narrow strips. Uzbek cotton pickers, judged on the weight of their harvest, would soak their cotton in water to make it heavier. Similarly, when America’s first transcontinental railroad was built, in the eighteen-sixties, companies were paid per mile of track. So a section outside Omaha, Nebraska, was laid down in a wide arc, rather than a straight line.

For that matter, think about our use of G.D.P. to indicate a country’s economic well-being. By that metric, a schoolteacher could contribute more to a nation’s economic success by assaulting a student and being sent to a high-security prison than by educating the student, owing to all the labor that the teacher’s incarceration would create.

The Art and Science of Remembering

The Art and Science of Remembering

  • “When retention was tested immediately after learning, both napping and cramming produced better retention than taking a break, but only the nap benefit remained significant when tested one week later,” the researchers concluded.
  • The quiz was then repeated a half-hour later and again a week later, and in both retests, the people who sat and did nothing for 10 minutes “remembered much more,” the researchers reported in the journal Psychological Science.

More Than A Perfect Score: When Are Kids Under-Challenged In Math?

  • Instead of seeing perfect scores as the benchmark for success, it’s time to start seeing them as signs that kids are under-challenged,
  • “We’re teaching kids that you have to get it right every time,” he said.
  • They’re also missing out on opportunities to tackle more challenging problems that will help them grow and develop.
  • What’s more, if kids aren’t presented with mathematical “challenges they won’t succeed at every time,” then the first time they encounter a real challenge, they often don’t know how to cope,

Technology Is a Huge Social Experiment on Children

  • While the private Waldorf School of the Peninsula, popular with Silicon Valley executives, eschews most screens, the nearby public Hillview Middle School advertises its 1:1 iPad program.
  • “….everything that’s happening around big data, AI, and that is not something that you’re going to be particularly good at because you have a cellphone in fourth grade,”

Make Your Daughter Practice Math. She’ll Thank You Later.

  • For parents who want to encourage their daughters in STEM subjects, it’s crucial to remember this: Math is the sine qua non.
  • You and your daughter can have fun throwing eggs off a building and making papier-mâché volcanoes, but the only way to create a full set of options for her in STEM is to ensure she has a solid foundation in math.
  • Math is the language of science, engineering and technology. And like any language, it is best acquired through lengthy, in-depth practice.
  • You can begin to avoid practicing it, because to your mind, that practice is more painful than learning what comes more easily. Not practicing, in turn, transforms what started out as a mere aversion into a genuine lack of competence. Unfortunately, the way math is generally taught in the United States — which often downplays practice in favor of emphasizing conceptual understanding — can make this vicious circle even worse for girls.
  • When we learn to play an instrument — say, the guitar — it’s obvious that simply understanding how a chord is constructed isn’t the equivalent of being able to play the chord


The Scientific Argument for Mastering One Thing at a Time

  • In fact, researchers found that people who tried to accomplish multiple goals were less committed and less likely to succeed than those who focused on a single goal.
  • But here’s the thing: automaticity only occurs as the result of lots of repetition and practice. The more reps you put in, the more automatic a behavior becomes.
  •  After 30 days, the habit is becoming fairly routine. After 60 days, the process is about as automatic as it can become. That said, the study cited above found the average habit takes about 66 days to become automatic

The Myth of ‘Learning Styles’


  • Instead, the visual learners performed best on all kinds of tests. Therefore, the authors concluded, teachers should stop trying to gear some lessons toward “auditory learners.”
  • This doesn’t mean everyone is equally good at every skill, of course. Really, Willingham says, people have different abilities, not styles
  • Husmann says the most important thing, for anyone looking to learn something new, is just to really focus on the material—that’s what the most successful students from her study did.



The Talent Code

Instead, the teachers and coaches I met were quiet, even reserved. They were mostly older; many had been teaching thirty or forty years. They possessed the same sort of gaze: steady, deep, unblinking. They listened far more than they talked. They seemed allergic to giving pep talks or inspiring speeches; they spent most of their time offering small, targeted, highly specific adjustments. They had an extraordinary sensitivity to the person they were teaching, customizing each message to each student’s personality.

On John Wooden: Gallimore and Tharp recorded and coded 2,326 discrete acts of teaching. Of them, a mere 6.9 percent were compliments. Only 6.6 percent were expressions of displeasure. But 75 percent were pure information: what to do, how to do it, when to intensify an activity.


Online teaching vs. Classroom teaching


  • If teachers were to teach as Salman Khan teaches in his videos they would be down rated. The math teacher who shows her class several very clear examples followed by some practice problems will be rated developing on the basis that she was too teacher centered, not engaging, and too focused on procedures.
  • Where was the student engagement? Why weren’t they sitting in groups? Where was your differentiation? Where was your student-centered instruction? Why no discovery based learning?




Learning Myths

  • Quizzing yourself on something you’ve just read is a great example of active learning, the best way to learn.
  • Research shows that deep subject matter expertise is a key element in helping teachers excel.
  • What is helpful is that [the feedback] comes close to when you perform the task, and that it requires you to generate an answer
  • Re-reading and highlighting are particularly ineffective. They’re just passive, and you are just kind of skimming that material.   If you’re preparing for a meeting, you’d be much better off just putting the material away and just asking yourself questions.
  • I think there’s so much stuff out there now that’s like, “Learning’s supposed to be easy, learning’s supposed to be fun!”
  • People underestimate how much they forget, and people who are able to revisit their learning at a regular rate end up learning a lot more.


The 10,000-hour rule is wrong and perpetuates a cruel myth


  •  For example, the number of hours of deliberate practice to first reach “master” status (a very high level of skill) ranged from 728 hours to 16,120 hours. This means that one player needed 22 times as much deliberate practice as another player to become a master.
  •  Deliberate practice left more of the variation in skill unexplained than it explained. For example, deliberate practice explained 26% of the variation for games such as chess, 21% for music, and 18% for sports.
  • Researchers found that there was a stronger correspondence in drawing ability for the identical twins than for the fraternal twins. In other words, if one identical twin was good at drawing, it was quite likely that his or her identical sibling was, too.
  • But it does imply that there are limits on the transformative power of practice. As Mosing and her colleagues concluded, practice does not make perfect.
  •  Jesse Owens, Marion Jones, and Usain Bolt, and found that, in all cases, they were exceptional compared with their competitors from the very start of their sprinting careers — before they had accumulated much more practice than their peers.

Slate  BI



Investment Returns and Geometric Mean

What if an investment returned 5%, 20%, and 50% over three years?
Year 1:  $100 * .05 = $105
Year 2:  $105 * .20 = $126
Year 3:  $126 * .50 = $189

What was the annual return?  Can you just average the percentages?
Let’s try it.  The average of 5%, 20%, and 50% is 25%
Did you average 25% a year?

Year 1:  $100 * .25 = $125
Year 2:  $125 * .25 = $156.25
Year 3:  $156.25 * .25 = $195.31

No, 25% for 3 years gets you a different amount!

You calculate the average annual return via the geometric mean (not the arithmetic mean)

\(\sqrt[3]{1.05 * 1.20 * 1.50} -1 = .236 \)

Your annual return was actually 23.6%

Year 1:  $100 * .236 = $123.6
Year 2:  $123.6 * .236 = $152.77
Year 3:  $152.77 * .236 = $188.82 …



  • How much did practice actually explain? A 2014 meta-analysis looked specifically at the relationship between deliberate practice and performance in music, games like chess, sports, education, and other professions.
  • For some things, like games, practice explained about a quarter of variance in expertise.
  • For music and sports, the explanatory power accounted for about a fifth.
  • But for education and professions like computer science, military-aircraft piloting, and sales, the effect ranged from small to tiny. For all of these professions, you obviously need to practice, but natural abilities matter more.

Studies show taking notes by hand is more effective

Take Notes by Hand for Better Long-Term Comprehension

  • The results revealed that while the two types of note-takers performed equally well on questions that involved recalling facts, laptop note-takers performed significantly worse on the conceptual questions.
  • The benefit of having more content is canceled out by “mindless transcription.”
  • The amount of verbatim overlap was associated with worse performance on conceptual items.

What You Miss When You Take Notes on Your Laptop

  • Mueller and Oppenheimer predicted that the decrease in retention appeared to be due to “verbatim transcription.”
  • And again, though the laptop note takers recorded a larger amount of notes, the longhand note takers performed better on conceptual, and this time factual, questions.

A Learning Secret: Don’t Take Notes with a Laptop

  • Students who used longhand remembered more and had a deeper understanding of the material