Many years ago, around 1967, in a popular magazine, I read a little reference that said that someone had studied the effect of caffeine on chess-problem solving. I wrote to the author asking him for his source. He cited an article "Effect of Caffeine upon Chess Problem Solving", by one Harald Holck. The article appeared in a respected professional journal, "The Journal of Comparative Psychology," 15, 1933, 301-311. Holck's address there was given as Department of Pharmacology, American University of Beirut, Beirut, Syria.I somehow found and wrote to Holck, who in 1968 was connected with the University of Nebraska. We had a brief correspondence, during which he sent me a copy of his Ph.D. dissertation, dated 1929, from the University of Chicago, and a copy of the 1933 article. I have saved these two items plus a long letter dated Sept 3, 1968. The letter asked me to return the cutting of the article, which I never did, to my regret. Surely by now Dr. Holck is deceased, so I suppose that doesn't matter.
The dissertation is titled "Diet and Efficiency." It is a experimental study mainly on the effects on mental activity of "Fletcherizing." Evidently, Fletcherizing is a method of eating proposed around 1903 by, guess, a man named Fletcher. Briefly, in Fletcherizing, the eater chews food much more than "normal." Fletcher believed that the special chewing had beneficial effects. Holck's dissertation describes several experiments in which subjects performed mental tasks while on, and not on, the Fletcher regime. You guessed it: one of the mental tasks was solving two-move chess problems. In all, the results showed that, on the Fletcher regime, the solvers did slightly better.
In the caffeine study, Holck extended the solving test to a a situation in which the solver received an injection of either saline or caffeine. In this case, the effect of caffeine was, at best, slight. Note: not coffee drinking to get caffeine.
Over the years, I've occasionally (rarely) wondered whether the chess problem world would care to learn of this insignificant work. I would call the work "quaint." In particular, if I were to write a brief summary, would Mat Plus be interested?
It's midnight here. Best wishes,
Newman