Thought for the day

My wife reads The New Yorker. I would too if I "had the time." The only time I read the magazine is when she recommends something.
    For example, she most recently said I should read an article by Jonah Lehrer from the Annals of Science column for December 13: "The Truth Wears Off," about "the decline effect," a difficulty scientists often have trying to replicate experimental results. Here's an example of the effect:

In 1991, the Danish zoologist Anders Møller...made a remarkable discovery about sex, barn swallows, and symmetry...[F]emale barn swallows were far more likely to mate with male birds that had long, symmetrical feathers. This suggested that the picky females were using symmetry as a proxy for the quality of male genes. Møller’s paper, which was published in Nature, set off a frenzy of research....
    In the three years following, there were ten independent tests of the role of fluctuating asymmetry in sexual selection, and nine of them found a relationship between symmetry and male reproductive success...Before long, the theory was applied to humans....
    Then the theory started to fall apart. In 1994, there were fourteen [emphasis mine] published tests of symmetry and sexual selection, and only eight found a correlation. In 1995, there were eight papers on the subject, and only four got a positive result. By 1998, when there were twelve additional investigations of fluctuating asymmetry, only a third of them confirmed the theory. Worse still, even the studies that yielded some positive result showed a steadily declining effect size. Between 1992 and 1997, the average effect size shrank by eighty per cent.

    What people who have studied this problem have concluded is that researchers are like the rest of us. "We like proving ourselves right and hate being wrong."

The problem, of course, is that such dramatic findings are also the most likely to get published in prestigious journals, since the data are both statistically significant and entirely unexpected. Grants get written, follow-up studies are conducted....
    This suggests that the decline effect is actually a decline of illusion. While Karl Popper (1902-1994) imagined falsification occurring with a single, definitive experiment—Galileo (1564-1642) refuted Aristotelian mechanics in an afternoon—the process turns out to be much messier than that. Many scientific theories continue to be considered true even after failing numerous experimental tests....

The article concludes a couple of paragraphs later with today's rather profound thought:

Just because an idea is true doesn't mean it can be proved. And just because an idea can be proved doesn't mean it's true. When the experiments are done, we still have to choose what to believe.

To me, the thought is all the profounder for applying to ordinary, everyday ideas and beliefs as well as to science.