Monthly Archives: December 2007

Scientific American Community has a fun short article about memory and Sleep.  The author summarizes a number of known results about the need for sleep in translating memory into deeper understanding.  (Apparently, sleep is valuable for “digesting” learning.  For instance, if you’ve been drilling over and over on a technique, sleeping on it may help you find a shortcut that you haven’t seen while awake.) 

However, the focus of the present article is on how going without sleep affects learning.  There has been a debate within the sleep community about whether sleep deprivation primarily hurts attention, or whether it hurts the ability to form memories also.  A number of studies have shown that attention suffers more severely from lack of sleep than other cognitive functions.  By contrast, rat studies show that the memory apparatus itself is less responsive in sleep-deprived animals — even after that apparatus is removed from the animal!

The study discussed in this article took a bunch of college students and used fMRI to study what regions of the brain were active.  Intriguingly, the sleep-deprived students who did best on the learning tasks had more activation of their attention network — though their memory network was still struggling.  Perhaps sleep deprivation most directly affects memory, and the affect on attention is less crucial. 

In any case, the lesson for this time of year is easy: get enough sleep before studying for exams!
John

Ian Ayres has a fun guest post on the Freakonomics blog.  His argument is that in many decision-making situations it’s best to have some degree of randomness in your decision, so your opponent can’t just play for you to do the "obvious" best move.  (These ideas are very relevant to me, since one of my favorite squash opponents is extremely good at reading my next shot.  Especially when I have a very likely winning position, he’ll guess what I’m going to do next, run to the killer position for that shot, and end up stealing the point.  Even knowing that I need to surprise him hasn’t helped so far.  I need a random number generator in my racket!)

The post also shows another example of human decision-making flaws: football coaches don’t go for it on 4th down nearly as often as the data suggests they ought to.  (There are a few notable exceptions, including Bill Belichek of the Patriots.  Interestingly, announcers *still* call him out for being inappropriately aggressive on 4th down.  How many Super Bowls does he have to win?!)

One commenter points out a possible evolutionary argument: perhaps football coaches who are aggressive look stupid when they lose, and hence get weeded out.  Fun argument!  Notice, however, that it requires an
accepted wisdom to conform to.  Where did that come from?  Perhaps it’s
possible to motivate the accepted wisdom from known human decision-making flaws: we tend to value something we already have more than something we might obtain in the future, irrationally.  (For instance, most people would value $100 more than a 60% chance at $200.) So, the accepted wisdom for football coaches might be to take the points they have "in hand", because the administrators who fire them might think they’re stupid if they don’t — even if the expected value computation says "go for it!".

There’s a related, but different argument in "Wisdom of Crowds": the players might lose heart if they go for it and miss, which might reduce their performance in the rest of the game, and hence their *actual* expected number of points.  This sort of psychological effect might be amplified by the ordinary human preference for the bird in the hand described above.

I’m particularly interested in these areas in which human decision-making is unable to take advantage of what the data suggest.  Could a decision aid help?  What would a decision aid for a football coach look like, for instance?

John

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A very interesting article on Read/Write Web summarizes a Hitwise report on traffic share on the Internet.  They have particular interest in the question of how different network categories are growing in the percent of their traffic that comes from search engines (versus other ways of getting to the sites). 

I’m disappointed that social web sites are not called out as a category.  I’d be very interested in seeing how much traffic to sites like Facebook come from search.  (I’d be similarly interested in the data on Flickr, though I’d like to see that separated out further from the more purely social social web sites.)  These sites are working to have users create content for other users; how often are those other users within the social network of the creators?  How often are their pages visible to the broader Internet?  What are the implications for the type of community that is being created?

John

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Today The Wired Campus had an article entitled Facebook: Not Just for Students Anymore. It discussed (briefly) the idea of professors setting up facebook profiles and issues this raises. This article linked to a longer piece, For Professors, ‘Friending’ Can be Fraught. This article is a slightly more melodramatic representation of facebook.

Granted, there are issues with faculty (and TAs) being on facebook. As a TA, I make it a point never to accept the friend requests of my students until the end of the semester once grades are submitted. But I have no problem with facebook friending my advisor, my undergrad profs, or other profs or staff within my research group. The trick seems to be in how people use facebook. I try to ensure that my page passes the mom test. I don’t have anything on my page that I wouldn’t mind my mother seeing. (For others this could be the Grandma test or the little brother test or, perhaps, the professor test.)

I enjoy having professors on facebook. It’s fun to see that you are beating your advisor at Scrabble (or vice versa) and that your minister has thrown a turkey at a professor (thanks SuperPoke). Sure I probably watch my content a little more closely than I did two years ago, but to be honest, it’s something that I should be doing anyways.