Popular, you’re [not] gonna be pop-​​yoo-​​oo-​​lar

John Allen Poulos asks, “Are your friends more pop­u­lar than you are?” Probably:

There doesn’t seem to be any obvi­ous rea­son to sup­pose this is true, but it prob­a­bly is. We are all more likely to become friends with some­one who has a lot of friends than we are to befriend some­one with few friends. It’s not that we avoid those with few friends; rather it’s more prob­a­ble that we will be among a pop­u­lar person’s friends sim­ply because he or she has a larger num­ber of them.

The rest is here. H/​t Paul Hsieh.

Testing & learning

Test-​​taking teaches stu­dents. This New York Times arti­cle describes research that sug­gests stu­dents learn more about a sub­ject by tak­ing tests about it than by study­ing it.

In the exper­i­ments, the stu­dents were asked to pre­dict how much they would remem­ber a week after using one of the meth­ods to learn the mate­r­ial. Those who took the test after read­ing the pas­sage pre­dicted they would remem­ber less a week later than the other stu­dents pre­dicted — but the results were just the opposite.

. . . .

Why retrieval test­ing helps is still unknown. Perhaps it is because by remem­ber­ing infor­ma­tion we are orga­niz­ing it and cre­at­ing cues and con­nec­tions that our brains later recognize.

When you’re retriev­ing some­thing out of a computer’s mem­ory, you don’t change any­thing — it’s sim­ple play­back,” said Robert Bjork, a psy­chol­o­gist at the University of California, Los Angeles, who was not involved with the study.

But “when we use our mem­o­ries by retriev­ing things, we change our access” to that infor­ma­tion, Dr. Bjork said. “What we recall becomes more recallable in the future. In a sense you are prac­tic­ing what you are going to need to do later.”

This fits my expe­ri­ence. I took my share of stan­dard­ized tests in grade school (I remem­ber tak­ing the Iowa Test of Basic Skills in ele­men­tary school). The sub­jects were usu­ally not that inter­est­ing, but I would recall the sub­jects and silly lit­tle facts from them years later. One 7th-​​grade test included a pas­sage about beriberi—a dis­ease caused by a vit­a­min defi­ciency linked to eat­ing pol­ished (white?) rice—that I still vaguely recall today.

Homeland insecurity

Anne Applebaum says that the Department of Homeland Security does not pro­tect America against ter­ror­ist plots. Yes, she says, “[t]errorists have been stopped since 2001 and plots pre­vented, but always by other means.” She continues:

After the Nigerian “under­wear bomber” of Christmas Day 2009 was foiled, DHS Secretary Janet Napolitano claimed “the sys­tem worked” — but the bomber was caught by a pas­sen­ger, not the feds. Richard Reid, the 2001 shoe bomber, was undone by an alert stew­ardess who smelled some­thing funny. The 2006 Heathrow Airport plot was uncov­ered by an intel­li­gence tip. Al Qaedas recent attempt to explode cargo planes was caught by a human intel­li­gence source, not an X-​​ray machine. Yet the TSA responds to these events by plac­ing restric­tions on shoes, liq­uids, and now per­haps printer cartridges.

It’s short: read the whole thing.

Lessons in tautology, Part I

From The New York Times’ Bits blog:

So the con­sen­sus is that Mr. McAdam will announce the iPhone on Verizon on Tuesday, and that the device will go on sale a few weeks after that. . . . [A]nother ques­tion is whether Apple exec­u­tives will be on stage at the New York event. Don’t count on Steven P. Jobs, the company’s chief exec­u­tive, to be there. Apple typ­i­cally announces new iPhone car­ri­ers through press releases. Then again, Verizon is not any other car­rier. So per­haps another Apple exec­u­tive will make the trip.