Field of Science

Why we want to believe chocolate makes us smarter

Eat chocolate, win Nobel Prize?

The New England Journal of Medicine published a study two weeks ago showing, amazingly, that eating chocolate might make you smarter.  To be precise, the author, Franz Messerli, was wondering if chocolate consumption might be correlated with the overall cognitive function of a population.  He couldn't find any data on national intelligence, so instead he used the total number of Nobel prize winners per capita.  The correlation between chocolate consumption and Nobels is remarkably strong, with a p-value less than 0.0001, meaning that the odds that this is due to chance are less than 1 in 10,000.

Ha ha! Dr. Messerli was just kidding.  Or was he?

The article itself reads like almost any science paper.  It includes a straight-faced presentation of the data and scholarly references suggesting that the brain-enhancing effect of chocolate might be due to flavanols, which may be "effective in slowing down or even reversing the reductions in cognitive performance that occur with aging."

In fact the entire article appears to be dead serious until the end, where Messerli makes the wry comment that
"The cumulative dose of chocolate that is needed to sufficiently increase the odds of being asked to travel to Stockholm [where the Nobels are awarded] is uncertain."
And then, in his disclosure of conflicts of interest, he reports "daily chocolate consumption, mostly but not exclusively in the form of Lindt's dark varieties."  Hmmm, this doesn't seem like a serious science paper after all.

Word of this article swept through the halls of academia the day after it was published.  I heard it being discussed among my colleagues, who were concerned that NEJM had published yet another example of misleading statistics.  It took a couple of days for us to realize that it was a joke - based on real data, but a joke nonetheless.

The media reported the story widely, and a few reporters figured out the ruse, but the parody was just too subtle for most.  Reuters wasn't fooled, as reported on their own site and on Fox News. They reached Messerli by phone, who confessed that
"the whole idea is absurd, although the data are legitimate and contain a few lessons about the fallibility of science."
The Associated Press reporters were slightly suspicious, opening with "take this with a grain of salt." But they went on to report it as straight news, and their story appeared on CBS News, the Huffington Post, and elsewhere.

Larry Husten, my fellow columnist at at Forbes, reported it as straight news with the headline "Chocolate and Nobel Prizes Linked in Study." Time magazine fell for it too.

Two medical websites, Medical News Today and WebMD, not only took the story seriously, but also bought into the explanation that the effect is caused by flavanols, which are found not just in cocoa, but also in red wine and green tea.  Sounds like an ideal diet to me.

Slate's Brian Palmer had an interesting angle. He reported the story as straight news, but then investigated why the Swiss eat so much chocolate.  (Answer: innovation in chocolate-making, and wealth.)

Why do we want to believe chocolate makes us smarter?  Well, obviously because we'd love for it to be true.  And as Messerli points out, there have been some serious studies linking flavonoids to better health and cognitive function.  But the notion that chocolate leads to Nobel prizes is a little too good to be true.  I'm reminded of the study that I wrote about back in April that claimed chocolate would help you lose weight - which was little more than wishful thinking masquerading as science.

Still, with Halloween just past, many parents are probably wondering how much to let their kids eat.  Those Nobel-champion Swiss consume about 11 kilograms per year, about 30 g (1 ounce) per day.  That's 3 of those little mini-chocolate bars.  And parents, maybe you should have a few too - just in case Messerli is right.

1 comment:

  1. My 85-year-old grandma debunked the article with the following research hypothesis (no joke!):

    The whole correlation should take climate or temperateness into account because the effect is most likely mediated or moderated by it.

    Her explanation: In hotter countries, chocolate melts too quickly and needs additives that spoil the taste of it. Temperateness and economic growth most certainly correlate, less hot climate thus enabling organized research and mediating chocolate consumption.

    The original paper states that "[d]ifferences in socioeconomic status from country to country and geographic and climatic factors may play some role, but they fall short of fully explaining the close correlation observed."

    There are statistical methods to test this claim and so my grandma and me can only conclude that the paper is a spoof (or very subtle viral marketing).

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