Friday, February 27, 2009

Overcoming Bias

I have a new Overcoming Bias post here.

Friday, February 20, 2009

Different Tastes

I love cilantro. I've even grown it at home. But some people hate it with a passion. Conversely, I understand (in a purely intellectual sense) that there are actually people in the world who like olives, but the smell and taste of olives is repulsive and nauseating to me.

Apparently there's at least some evidence that the taste for cilantro is affected by genetics, but I wonder what functionality there is for genes that switch on a heartfelt aversion to completely harmless foods.

Thursday, February 12, 2009

Sleep Necessary to Form Memories

I thought this study was interesting:
In research published recently in Neuron, Marcos Frank, PhD, Assistant Professor of Neuroscience, at the University of Pennsylvania School of Medicine, postdoctoral researcher Sara Aton, PhD, and colleagues describe for the first time how cellular changes in the sleeping brain promote the formation of memories.

"This is the first real direct insight into how the brain, on a cellular level, changes the strength of its connections during sleep," Frank says.

The findings, says Frank, reveal that the brain during sleep is fundamentally different from the brain during wakefulness.

"We find that the biochemical changes are simply not happening in the neurons of animals that are awake," Frank says. "And when the animal goes to sleep it's like you’ve thrown a switch, and all of a sudden, everything is turned on that's necessary for making synaptic changes that form the basis of memory formation. It's very striking."

Tuesday, February 10, 2009

Self-Fulfilling Prophecies

Coyote Blog makes an excellent point:
At what point do politicians bear some public accountability for their public statements and the effect those statements have on the economy? I almost want to ask Obama and Pelosi — what is the minimum size of pork-spending bill you will accept so we can just go ahead and pay the money and get you and your cohorts to shut the hell up on trying to convince everyone we are in the Great Depression. Because, to some extent, such statements can be a self-fulfilling prophesy. . . .

Now, I suspect that I would have a different observation if I lived in Detroit, but I ask every business owner or manager I meet for the personal evidence they have of economic cataclysm. Is their business down? And in a surprising number of cases, I get the answer that their business is doing OK, but they are cutting back because surely the worst is soon to come, based on everything they see in the media. And do you know what? I have done exactly the same thing. I had one bad month, but since then things have been pretty steady, but I am cutting like crazy anyway, because I can’t ignore the only other information source I have on the economy, which are pronouncements in the media.

I strongly believe that public pronouncements of doom, starting last October with Henry Paulson and continuing now to almost daily excess by Obama (today’s statement: the economy is in a “virtual free fall”) have measurably contributed to job losses in this country. Many people who are on the street without a job today can probably trace their unemployment to “just in case” cuts made more in response to government assurances of doom as on actual declines in output.
Another data point, a pretty big one: at a dinner last week, I happened to be seated next to a Wal-Mart recruiter. He said that the CEO of Wal-Mart USA just issued a complete hiring freeze, canceling all open positions. If anyone at Wal-Mart corporate wants to hire anyone for any position, they have to write up a new job description and prove the necessity for it. The recruiter added that Wal-Mart has done fine so far, but that the CEO took this step because he wants Wal-Mart to have a "nest egg just in case" the economy does continue to get worse. But of course, when companies the size of Wal-Mart issue a hiring freeze without any business necessity beyond apprehension about the future, that contributes to an economic downturn. I suppose it's a collective action problem as well: if everyone could simultaneously agree not to cut back on hiring, things might stabilize, but as an individual company, you don't want to be the only one who failed to cut expenses when everyone else fired the workers who now can't afford to shop at your firm's outlets.

Don't Take Your Vitamins

A massive study has found that there is no measurable health benefit from taking a daily multi-vitamin. There are many such studies as to individual vitamins, with some studies even finding that Vitamins A and E are harmful.

I take several capsules of fish oil, 5,000 IU of Vitamin D, and -- the benefits of this are a bit more speculative -- alpha-lipoic acid and acetyl-l-carnitine. Alpha-lipoic acid is a powerful antioxidant, and several studies1 suggest that along with acetyl-l-carnitine, it can reverse the aging process and improve brain functioning. But who knows: in another 10 or 15 years, some massive study may show that these supplements aren't useful either.

1The studies are these:

Jiankang Liu, David W. Killilea, and Bruce N. Ames,
Age-associated mitochondrial oxidative decay: Improvement of carnitine acetyltransferase substrate-binding affinity and activity in brain by feeding old rats acetyl-L-carnitine and/or R-alpha-lipoic acid, Proceedings of the National Academy of Sciences, vol. 99, no. 4 (Feb. 19, 2002): pp. 1876–1881;

Tory M. Hagen, Jiankang Liu, Jens Lykkesfeldt, Carol M. Wehr†, Russell T. Ingersoll, Vladimir Vinarsky, James C. Bartholomew, and Bruce N. Ames, Feeding acetyl-L-carnitine and lipoic acid to old rats significantly improves metabolic function while decreasing oxidative stress, Proceedings of the National Academy of Sciences, vol. 99, no. 4 (Feb. 19, 2002): pp. 1870–1875;

Jiankang Liu, Elizabeth Head, Afshin M. Gharib, Wenjun Yuan, Russell T. Ingersoll, Tory M. Hagen, Carl W. Cotman, and Bruce N. Ames, Memory loss in old rats is associated with brain mitochondrial decay and RNA/DNA oxidation: partial reversal by feeding acetyl-L-carnitine and/or R-alpha-lipoic acid, Proceedings of the National Academy of Sciences, vol. 99, no. 4 (Feb. 19, 2002): pp. 2356–2361.

Friday, February 06, 2009

Followup on Alfie Kohn and Content Knowledge

Dan Willingham, a cognitive psychologist, has a critique of Alfie Kohn's educational writings; Kohn responds here.

In an earlier post, Willingham explains why content knowledge can't be separated from critical thinking skills, and Robert Pondiscio follows up on that point with a hilarious discussion of an experiment in which children were unable to figure out that a "tree octopus" website was fake.