This stinks of p-value hunting.
I can only imagine the study went like this. They did all these tests and then found that there were no statistically significant improvements after using these drugs. So they said to themselves, how can we tweak the parameters so as to get something publishable? Sure, let's eliminate an entire class of games where our control group does better than the test subjects.
Problem is, the most likely explanation for this is that people on these drugs spend more time thinking, and longer think time naturally is correlated with better results. But that's not how chess is played, else we'd all spend five hours on each move. Chess is about bounded rationality. As a result it looks to me that that they biased the results as to naturally achieve a desired effect.
Without any other tools (as in, pencil and paper to note conclusions), do you really think you could make a more effective move given five hours?
I mean - if the conclusion of the study is actually that use of drugs gave players a larger personal time bounds within which to think up a move, that's still significant.
I don't know about you, but my #1 blocker for productivity is how long I can actually concentrate on something. If a drug lets me focus for 10% longer, even if it doesn't improve my capabilities while focusing, that's still huge.
Edit: But you're not wrong, it does stink of p-value hunting. On the other hand, if your experiment is expecting one correlation, and instead you find another... then the p-value hunting was the correct move...?
As to visualization without pen and paper, the best blindfold players can keep track of a whole board in their mind, and explore variations deeply without losing track of the current state of the board or forgetting about the key variations they found along the way.
It sounds like you're into chess more than me, so I'm sure you know most of this stuff, I'm just noting it for other people in the thread.
I play on chess.com from time to time and I perform much better in games where I have a few days to make a move vs games that are played live with a timer. So for me, absolutely, if I have time to analyze I will almost always make a stronger move. I don't need to write down conclusions, I can just stare at it longer.
at best you'd have to make corrections to your p values to account for the fact you're conducting multiple tests. those corrections weaken the results. (i did not check this paper to see if they did the corrections.)
https://en.wikipedia.org/wiki/Correspondence_chess
I know you've said "other tools" (like miniboards) but even in your head, more time is an advantage.
Edit: I wouldn't play a match with five hours time, not even for the whole game. I take that "five hours" was hyperbole.
But the study we are talking about didn't give their players anything near such time, only rapid chess was played, where each player gets 15 minutes for the entire game. In rapid chess, time management is a crucial part of the game so it is very strange that they decided to eliminate games where a player ran out of time.
And the effect of amphetamines is improved focus (as well as slight euphoria and wakefulness) BUT one possible problem is that people lose control of what they focus on and tend to get lost in the details. I. e. you start out writing a letter and end up reading about 18th century calligraphy.
This is a common misconception: https://en.wikipedia.org/wiki/Hyperfocus
"It is typical for individuals with ADHD to say they 1), cannot focus on boring things and 2), can only focus on stimulating things, and that focus is often extreme. Thus it is both a concentration deficit and over-concentration, or generically: "hyperfocus." More concisely, some types of ADHD are a difficulty in directing one's attention, not a lack of attention"
Correspondence chess is a thing though
I can improve my chess rating in short time controls by a good 50+ points just by reminding myself to move quickly.