Last week, the British journal Practical Neurology published a study examining the link between a country’s milk consumption and Nobel prizes. As it turns out, countries where people drink more milk produce more Nobel laureates. Research indicating a similar link between chocolate consumption and Nobel prizes was published in the New England Journal of Medicine last year.
But what do they mean? Does milk make you smart? Or does chocolate make you smart, while also making you want to drink milk? Is milk chocolate more intellectual than dark chocolate? Are the scientists who wrote the milk paper serious when they advise aspiring Nobel winners to “strive for synergy with hot chocolate”? Or does the causation go the other way, and it is enhanced cognitive performance that stimulates chocolate consumption, which leads naturally to a glass of milk?
The answer, alas, is no.
“It’s only tongue in cheek,” said Franz Messerli, the New York doctor who did the chocolate analysis. “Those among us who are in medicine and do research, they’ll immediately realize that this basically is a joke.”
At the same time, both studies make a serious point about the interpretation of statistics, and the frequently overlooked difference between correlation and causation.
This is a good example of the cum hoc ergo propter hoc logical fallacy. The Latin phrase is translated as “with this, therefore because of this.” In short, it means that correlation does not imply causation. Frederic Bastiat called this “the greatest and most common fallacy in reasoning.”
It serves as the basis for many spurious attacks on liberty. For example, the phenomenon of the business cycle, characterized by economic booms and busts, is commonly attributed to the unhampered free market. The conclusion is then made that more government regulation of free market activity is required in order to avoid recessions and depressions. This is welcome news to politicians and bureaucrats.
But the critics of the free market miss the actual culprit: government manipulation of the money supply, which artificially lowers the market rate of interest and causes entrepreneurs to engage in a process of mass malinvestment of scarce resources.
Correlation does not imply causation. Don’t be fooled.
You can read the rest of the article at nationalpost.com.