The drugs are methylphenidate, which is most commonly marketed as Ritalin (by Novartis), and modafinil, which is sold as Alertec, Modavigil and Provigil. The study also measured the effects of caffeine and found, not surprisingly, that it also had an ameliorative impact.
When adjusting for an unexpected side-effect of the drugs on decision-making behavior – paradoxically, that they made the subjects play slower — the study found modafinil improved the players’ performances by an average of 15 percent, methylphenidate by 13 percent, and caffeine by around 9 percent.
https://worldchess.c...rugs-for-chess/
Okay, fine, just modafinil, which we already knew about, but the exact pattern is interesting. Modafinil makes people take longer to make their moves, but the moves are ultimately better. That suggests that its advantage is not increasing IQ per se, but in giving people the increased attention span/concentration to work harder on finding good moves. I think this elegantly ties together a lot of stuff into a good explanation of modafinil’s cognitive-enhancing properties.
Edited by VP., 15 February 2017 - 12:53 PM.