Wednesday, April 23, 2008

Persistence of Memory

OK, I want you to read this article:

It is a long article, ostensibly about Piotr Wozniak, a Polish programmer who developed a learning software program called SuperMemo. But the article contains much more than that: It talks about the history of cognitive neuropsychology, of the "spacing interval" effect in how we learn and forget, the reason cramming does not work, the reason why repetition does work, and lot more. If you are not familiar with this idea, below is the so-called "forgetting curve" from the article

A lot of the way we teach is based on a complete ignorance of some very basic psychology. Students need to see material again, and the repetition needs to come at increasing, rather than fixed intervals. And then there is this (from the discussion of the components to log term memory - retrieval strength and storage strength. Emphasis is mine) -

One of the problems is that the amount of storage strength you gain from practice is inversely correlated with the current retrieval strength. In other words, the harder you have to work to get the right answer, the more the answer is sealed in memory. Precisely those things that seem to signal we're learning well — easy performance on drills, fluency during a lesson, even the subjective feeling that we know something — are misleading when it comes to predicting whether we will remember it in the future. "The most motivated and innovative teachers, to the extent they take current performance as their guide, are going to do the wrong things," Robert Bjork says. "It's almost sinister."

Student evaluations, anyone? Anyway read the article, it is terrific.

Saturday, April 05, 2008


It has been spring in Louisiana for a good two weeks now. Around here the dogwoods are in bloom, bright splashes of impressionistic white dots in the emerging green of the woods. Great shoals of azaleas make their brief appearance. Redbuds have bloomed purple in the midst of oaks and sweet gums; the black gum in my backyard is tardy as always, the last tree to put out its leaves and the last to let them go.

Over Easter we made of our favorites trips, riding along the Tammany Trace "rail to trail" bike path. We parked on the middle of Abita Springs, one of the prettiest towns in Louisiana and home of a truly great brewery, and rode our bikes from Abita Springs to Mandeville on the north shore of Lake Ponchartrain, and then over to Fontainebleau State Park. Jst as we were leaving we saw this Barred Owl just a few feet off the trail:

I love Fontainebleau - gorgeous ancient oaks that you cannot wrap your arms around, tired old limbs reaching down and growing into the ground. I was very afraid that they had been damaged by Hurricane Katrina, but those fears were misplaced. These old wonders have seen at least four or five Hundred Year Storms, and they'll see a few more. Only one of the great oaks seemed in bad shape, and I think it was sick the last time we were down.

The next day, Easter Sunday, we went down to New Orleans, touring the Aquarium of the Americas and the National World War II Museum. Both are open and in great shape. The WW II museum is always a very emotional experience for me, and it was the first time Carol and Ben had toured it. Afterwards we all felt drained, and decided to come back home that night.