Proven: Performance-enhancing drugs for chess

1/25/2017 – It is the first time that drugs have been found under rigorous scientific conditions to improve chess performance. The results of the ground-breaking study have been published in a leading scientific journal. The drugs are methylphenidate, which is most commonly marketed as Ritalin, and modafinil, which is sold as Alertec, Modavigil and Provigil. They improved the players’ performances by an average of 13 and 15 percent, while caffeine, which also has an ameliorative impact, improved it by around nine percent. Report in WorldChess.com.

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New Study Finds Performance-Enhancing Drugs for Chess

By Dylan Loeb McClain

Since 1999, the World Chess Federation, which is also as known as FIDE, has had scorn regularly heaped on it for having a drug testing policy and for testing top players at major events. The federation did not put the policy in place because it believed it had a drug problem, but to satisfy the International Olympic Committee, which requires that all sports that it recognizes have such a program.

The idea that chess might one day be in the Olympics continues to seem like a pipe-dream, but it turns out that testing for drugs may have been a prescient move. A landmark study published in European Neuropsychopharmacology, the official publication of the European College of Neuropsychopharmacology, has found that there are two prescription drugs that seem to enhance chess-playing ability.

Abstract: Methylphenidate, modafinil, and caffeine for cognitive enhancement in chess: A double-blind, randomised controlled trial

Stimulants and caffeine have been proposed for cognitive enhancement by healthy subjects. This study investigated whether performance in chess – a competitive mind game requiring highly complex cognitive skills – can be enhanced by methylphenidate, modafinil or caffeine. In a phase IV, randomized, double-blind, placebo-controlled trial, 39 male chess players received 2×200 mg modafinil, 2×20 mg methylphenidate, and 2×200 mg caffeine or placebo in a 4×4 crossover design. They played twenty 15-minute games during two sessions against a chess program (Fritz 12; adapted to players’ strength) and completed several neuropsychological tests. Marked substance effects were observed since all three substances significantly increased average reflection time per game compared to placebo resulting in a significantly increased number of games lost on time with all three treatments. Treatment effects on chess performance were not seen if all games (n=3059) were analysed. Only when controlling for game duration as well as when excluding those games lost on time, both modafinil and methylphenidate enhanced chess performance as demonstrated by significantly higher scores in the remaining 2876 games compared to placebo. In conjunction with results from neuropsychological testing we conclude that modifying effects of stimulants on complex cognitive tasks may in particular result from more reflective decision making processes. When not under time pressure, such effects may result in enhanced performance. Yet, under time constraints more reflective decision making may not improve or even have detrimental effects on complex task performance.

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.

The results would seem to pose an immediate challenge for FIDE and for tournament organizers around the world. Cheating by using high-powered computers has become a problem in recent years, with even some top-level players being caught. Now, if the results of this study are borne out, players could use a chemical means that is invisible to the eye to boost their performance.

The new study, which was conducted by 13 professors and researchers from several German universities and the University of Stockholm, is titled, “Methylphenidate, modafinil, and caffeine for cognitive enhancement in chess: A double-blind, randomized controlled trial.”

Methylphenidate and modafinil have been around for years – in the case of methylphenidate, since the early 1960s. Both are stimulants. Methylphenidate is commonly used to treat attention deficit hyperactivity disorder (ADHD), while modafinil is often used for narcolepsy and other sleep-related disorders.

Dr. Klaus Lieb, a professor of psychiatry and psychotherapy at the University of Mainz in Germany, and one of the study’s main authors, said that the researchers wanted to see whether people who already were performing at a high level mentally could have their performance enhanced through chemicals.

“There are lots of data showing that a subject in a sleep-deficient state or exhausted people do profit from an enhancer,” Dr. Lieb said. “We were really interested to show whether it is possible to show an enhancement effect, or a hyper performance effect in subjects who already perform at the top level of their cognitive performance.”

Dr. Lieb said that the researchers went into the study with the expectation that the stimulants would not show much benefit. “We primarily thought that it is not possible to enhance high cognitive tasks and were astonished to find such results,” he said.

Chess players were chosen as the subjects in part because several of the researchers play. (Harold Ballo, who works with Dr. Lieb, has a FIDE rating of 1981.) In addition, the fact that computers could be used as sparring partners and their strengths calibrated to equal that of the subjects made chess an ideal laboratory.

The study recruited 39 rated players (40 when it began, but one dropped out). Each player was given a series of neuropsychological tests and questionnaires and then asked to play against computers running the chess-playing program Fritz 12. In their games, the players had 15 minutes total for their moves, the computers had six. Before each set of 10 games, the players were given either methylphenidate, modafinil, caffeine, or a placebo. In total, 3,059 games were played over a several-week period.

The results contained one surprise: The amount of time that the players took in their games when they were on the stimulants increased, so much so that more games were lost on time when players were taking the drugs than when they had taken a placebo. That skewed the results. When those losses were factored out, leaving 2,876 games (or data points) the benefits of the drugs became clearer.

The study’s conclusion addressed the additional thinking time as a critical component of the effect of the stimulants. The authors wrote, “This suggests that neuroenhancers do not enhance the quality of thinking and decision-making per time unit but improve the players’ ability or willingness to spend more time on a decision and hence to perform more thorough calculations.”

Dr. Lieb said that there are two caveats to the results. One is that they must be replicated by additional studies before it would be possible to say with some degree of certainty that the drugs enhance performance.

The second was that the study contained a flaw: the games were too quick, creating the problem of time-forfeits in some games. Additional studies would need to have the subjects play longer games.

That also suggests that if the drugs do turn out to definitely be performance-enhancers, they would be most useful in classical, or slow, tournament games rather than in rapid or particularly blitz games.

It is possible that some players already use these drugs. As part of the research for the new study, Dr. Lieb said that he and his colleagues contacted 1,500 players in the German federation and had them fill out surveys. Based on those surveys, he said that they had some idea of the prevalence of the two drugs among the chess-playing population. Dr. Lieb would not reveal the results as he said they hope to interest another scientific journal in publishing them.

Dr. Lieb cautioned that while the drugs seem to boost performance, taking them was not a good idea. “Their use may cause severe side effects and dependency, especially with repeated use,” he said.

Dr. Lieb was clear on one effect he thought the research should have. He said, “We recommend to introduce rigorous doping controls in chess competitions.”

The above article is reproduced from the news page of WorldChess and reproduced with the kind permission of the author.

Dylan Loeb McClain is a journalist with more than 25 years of experience. He was a staff editor for The New York Times for 18 years and wrote the paper’s chess column from 2006 to 2014. He is now editor-in-chief of WorldChess.com. He is a FIDE master as well.


Topics Doping, drugs
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K_Kara87 K_Kara87 7/24/2017 04:46
I didnt like the end of it. If it is increases chess playing ability it shouldnt be banned, it should be used! I dont care what people care about fairness etc. I want my brain function better (probably like most people in the world) This is nothing like using chess engine or asking another. Your brain is doing that and doing it better which is nice. May be better working brain give me more ratings, more money, may be it will keep me alive longer. May be i will discover something great and earn nobel prize. Only thing matters is improvement in my life conditions, whether you like it or not most people think same way and should. The only remaining question mark is side-effects. Is it -EV or +EV for my life quality. Increased performance in my brain function can overweight side effects of the drugs or side effects are severe that they do more harm then they help ?
Jacob woge Jacob woge 1/28/2017 11:08
@benedictralph

That's a good point.

Chess lends itself to studies like this because effects are so easy to measure. At least on paper. You don't have to invent metrics. Except for tie-breaks, but that's another story ...

Then the conclusion may be generalised to other fields of mental performance.

Btw, at first I thought the 9-15% performance improvement (eliminating some losses) was based on performance rating. For 2000 player, that's 200-300 Elo points, rather than the 60 given above. But that is construed, the study uses KISS, i.e. point score.
benedictralph benedictralph 1/28/2017 02:33
@Jacob woge:

What I find borderline miraculous is that in 2016/17 any funding body has decided to fund anything related to chess at all. Given the reception "controversial" chess research typically gets on this site, even the minimum amount of funding dollars (which certainly influences how thorough such studies can be in the first place) will likely be reduced or removed altogether. The research has passed the standard academic review process. It should be respected for at least that. Since we apparently have so many "qualified" researchers and scientists posting here as well, perhaps they could apply for funding to debunk this topic rather than just comment anonymously on some website. At least that would count in the scientific literature and increase interest/citations on chess research topics.
Jacob woge Jacob woge 1/27/2017 11:11
"The chess-playing community is generally quite hostile toward scientific findings; especially if it doesn't agree with their preconceptions."

Science in general? I don't think so. Not more than Average Joe.

Chess science in particular? Let me quote N Short (NiC):

"If chess is a vast jungle, computers are the chainsaws of a giant environmentally insensitive logging company."

There is an ongoing effort from computer science to 'solve' chess. This may, who knows, ultimately lead to the death of the game. Postal chess, adjournments, gone. Which is the next chess species to go extinct?

Chess analysis gives way to chess as sport. But I think a lot of chess players do not regard chess as sport at all: it's not the result, it's the game. If our opponent plays a little better than he used to is irrelevant, or even welcome.

Some recent rule changes (zero- (=in) tolerance a.o.) lead to games being decided off the board. I can easily imagine both players, winner and loser, ending up dissatisfied. Doping control is one more way of getting decisions off the board. That is undesirable. After all, we have come to play chess.

The real issue is cheating using electronical aid and/or collusion. Doping control, in comparison, is little more than a non-sensic pestilence.

This study, flawed as I have come to think it is in its willingness to bias the results, does not prove, but "proves" that doping is effective. Such a conclusion, if accepted, may lead to a worsening of playing conditions for the ordinary chess player (if such a creature exists). That would explain the lack of welcome.
Jacob woge Jacob woge 1/27/2017 10:32
By the way, sugar (chocolate, soft drink) very likely enhances performance. You know when you need it. We don't call that a drug, and how can you give placebo chocolate. But its effect, or rather, the effect of deprivation, could be just as strong as the substances tested. Could perhaps serve as a baseline? Stronger or weaker effect than plain sugar.
Jacob woge Jacob woge 1/27/2017 10:26
"Or maybe I am not understanding what you mean. "

Just what I wrote: "Increased thinking time is not necessarily linked to more thorough calculations."

Observation is: more time spent. Conclusion is: more thorough calculation. That conclusion is unsubstantiated. It would be correct, were we dealing with computers: number of plies steadily increases. But these are hoomin' beings. Time can be spent in a number of ways, other than thoroughness. Repetition, for one thing.
Petrarlsen Petrarlsen 1/27/2017 05:09
@ psamant and @ joshuar :

"Dr. Lieb said, “We recommend to introduce rigorous doping controls in chess competitions.” I completely disagree... if indeed the study is correct, I would say go ahead and allow for the drugs if it results in better moves and better games :-)" (psamant)

"Should stimulant meds be banned from chess competition? Probably. But not because of this article's results, but rather the large body of evidence and scientific literature supporting improved performance in tasks similar to chess." (joshuar)

In fact, in my opinion, yes, the kind of substances used for this study must be forbidden from competitive chess (I don't agree with psamant on this point), but not for the reasons stated by joshuar.

The problem isn't that they improve performance (I would completely agree with psamant that this would indeed be a positive point, and I don't agree with joshuar on this point), but that they are dangerous for the health of the players. Even caffeine, taken in too large quantities, can be very dangerous : I think that, for example, there is a general consensus on the point that the french writer Honoré de Balzac, who died when he was only 50 years old, literaly poisoned himself with enormous quantities of coffee. (Which doesn't mean, in my opinion, that caffeine must be forbidden altogether - for caffeine, it seems to me obvious that what must be forbidden must only be to take a great quantity of caffeine.)

So, my opinion is simply that it wouldn't be a "fair trade" to have better quality games, if the health of the players would be the price to pay for it...
joshuar joshuar 1/27/2017 02:12
Statistics aside, however, I have no reason to doubt the study's results. Stimulant medications have clear impacts on performance in cognitive tasks (think of all those college kids using them illegally for improved school performance, or this very article's neuro-psych testing component). The authors were lying when they stated that they didn't expect to see a positive results (else they wouldn't have performed the study!). Yes, the study was flawed. There were too few participants, forcing them to use a cross-over or repeated measures design, and perhaps not even providing the power to achieve significance even if in reality the stimulants cause such great effects. And yes their chosen game duration was too short, but you might imagine that if they made them longer, they would lose out on study participants willing to play so much chess for them!

Should stimulant meds be banned from chess competition? Probably. But not because of this article's results, but rather the large body of evidence and scientific literature supporting improved performance in tasks similar to chess.
joshuar joshuar 1/27/2017 02:12
Mr. McClain,

I appreciate your responding to comments on this interesting article; however, you may wish to refrain from such personal attacks as you claim are directed at you. I appreciate clarifications and additions that you did not have room for in the article, but you clearly believe in its significance more than you simply wish to present us with its existence, which can turn the comment field into more of an argument than a discussion when paired with readers looking for a fight. For example, rude comments about percent scoring aren't necessary, simply state that the percent was reflecting player scoring. When I first read your article, I wrongfully assumed percent improvement implied something like how often player moves agreed with computer "best moves" and then calculating a percent improvement in matching "best moves" with stimulant meds.

For my own comments: I am an MD and well versed in reviewing the significance of peer reviewed articles such as these. As you say, it's an interesting article. It doesn't prove anything, but it certainly opens the doors for further research. Why doesn't it prove anything? Simple, the results are not statistically significant. (As other readers have pointed out. You can't simply discount lost games because they were lost on time or control for length of the games after the fact. This is especially true if you assume that amphetamines will improve your concentration and reduce distraction. Why do you suppose, phsyiologically, that these players were taking more time on their moves? They weren't lazy. They took the time to look for the complications and double check their calculations. I'm sure they made better chess moves. But it's not like these medications made them forget about the clock. Rather, one could easily imagine that these games lost on time were difficult positions that would have, surprise surprise, also been lost on the board more often than not.)

I do not have access to the article, so someone would have to provide me some p-values (very unsusual not to provide these in the abstract!), but the general rule is to set your bar such that when you publish a positive result, there is only a 5% chance that your result was a false positive that came about by bad luck. Even at that level of confidence, though, that still means that one in twenty studies could be falsely positive, and that doesn't even take into account everyone who did the same research but didn't come close to a positive result and couldn't get a journal to publish their "attempt." That said, in this article's case, the other important thing to note is that articles such as these are probably rare because there is no medical or scientific reason people should be taking amphetamines to play better chess. It's dangerous, and no one has an interest in funding such a study, so scientists aren't going to spend time researching it, for the most part.

More glaring than the lack of p values is the fact that these 15% and 9% improvements weren't seen unless they got rid of all games lost on time AND "controlled for game duration." ("Only when controlling for game duration as well as when excluding those games lost on time..." from the abstract). That suggests some extra manipulation of the data, and surely requires replication in an additional study before buying these results as valid.
psamant psamant 1/27/2017 10:52
Hi,
Everyone seems to be commenting on the correctness of the study, etc. I would like to comment on the conclusion:
Dr. Lieb said, “We recommend to introduce rigorous doping controls in chess competitions.”
I completely disagree... if indeed the study is correct, I would say go ahead and allow for the drugs if it results in better moves and better games :-) Chess is fundamentally different from running races. A race has almost zero value after it is run... the replay of a past race is a non event. I know of chess lovers who go through chess games from the 1800s. Beginners learn chess by seeing how moves evolved over the past centuries. A game of chess is immortal... so anything that makes for a better quality game should be permitted!
Nostalgiac1972 Nostalgiac1972 1/27/2017 07:22
What?? It is not April yet, is it??
fgkdjlkag fgkdjlkag 1/27/2017 02:21
I know that's not what you said. I was paraphrasing the gist of it. You said:

"Increased thinking time is not necessarily linked to more thorough calculations. Lack of confidence. Calculations going in a loop. Inability or unwillingness to make a move. "

But that doesn't apply to this study. The players are given a drug that causes them to think longer. In your examples, lack of confidence, calculations going in a loop,a nd inability or unwillingness to make a move cause the longer thinking time, and not the other way around.
Or maybe I am not understanding what you mean.
Magic_Knight Magic_Knight 1/27/2017 12:29
What about Naka constantly on the Redbull? Are they eventually going to realize that makes no difference? LOLLLL
Jacob woge Jacob woge 1/26/2017 10:21
"the other benefit of this type of study design (there are a plethora of research study designs that have to be selected for the particular task) is that one wouldn't have enough power if the 39 players were divided into 4 groups. "

I would not consider that a benefit. I consider it a drawback - imposed by having not as many subjets as one would like. But given that, it's the best one can do.
Jacob woge Jacob woge 1/26/2017 06:52
"I disagree that more time spent does not result in increased calculation"

Strictly speaking, that is not what I said.
fgkdjlkag fgkdjlkag 1/26/2017 05:12
@Dylan McClain, it's nice to have an author of an article responding to comments. It is not that common on this site.
I worked full-time as a researcher. The other commenters are right. It is not correct to exclude losses. Statistical significance is determined before a study and it is a binary variable. The result is either statistically significant, or it is not. In this case, when the losses are included, the result is not statistically significant. There are persons who talk about a "trend" toward statistical significance, which is what you seem to be describing when losses are included, but this sort of language is not really correct.

This does not mitigate a very interesting study that clearly shows significant cognitive effects of these substances. I have not had a chance to read the paper, but a question is when they controlled for time, was it for total duration of the game or individual time thinking. It seems that there are negative consequences of using these drugs that may offset the performance benefit. Hard to say definitively what would happen for longer time controls, but one might be able to infer from other studies on these substances.

@dofski, I think you mean to use "eg" instead of "ie."

I don't interpret the comments here to be overly harsh. If the paper itself (not even the article) were given to a group of academics, you would get similar comments, perhaps just not worded as strongly.

@Jacob woge, the other benefit of this type of study design (there are a plethora of research study designs that have to be selected for the particular task) is that one wouldn't have enough power if the 39 players were divided into 4 groups.

I disagree that more time spent does not result in increased calculation. Certainly there will be exceptions, but if you force someone to take more time on a chess move before playing, there is going to be more calculation, even if not a linear increase. And we know that these drugs can increase concentration.
benedictralph benedictralph 1/26/2017 01:29
@Dylan:

The chess-playing community is generally quite hostile toward scientific findings; especially if it doesn't agree with their preconceptions. I'm just an average player so I don't suffer from this problem as much. No point arguing with them as they are likely to gang up on you as well. Let the research speak for itself or be validated/rejected with time (i.e. more research).
flachspieler flachspieler 1/26/2017 12:29
Back in his 1979 book, Kortschnoj had one paragraph where he described that he experimented with enhancing drugs in his chess career.
Mr TambourineMan Mr TambourineMan 1/26/2017 12:24
I also want to express myself sarcastically for how can you be so stupid that you filters out loss of time? So another little criticism. The subjects spend more time around the move 10-15 when they are not on the placebo. It may be because the drugs make it difficult to remember their opening repertoire which is obviously not so brilliant and might be the reason why they later lose out on time ... OH NO THEY'LL DIDNT LOSE ON TIME
IT WAS FILTERED OUT...
Timothy Chow Timothy Chow 1/26/2017 12:02
Paul Hoffman reported on his own (successful) experiments with performance-enhancing drugs for chess in his 2007 book "The King's Gambit." So it surprises me that it's taken so long for such a study to make headlines.
Giddy Giddy 1/25/2017 11:09
#Jacob woge
You are correct that all players underwent the same protocol. The method that was used, called cross-over design, ensures that everyone gets both the experimental treatment and the control treatment (placebo) in a random order. Thus, every player´s abilities on drugs can be compared to their own abilities on placebo.
So the test group and control group are the same people, which makes sure that the results cannot be confounded by differences between people in the compared groups.

This is a well accepted scientific method and considered very reliable.

I agree with you that the statement that taking more time per move equals more thorough calculations isn´t completely accurate. Unfortunately, I can not read the full article, but from the abstract it seems the authors of the paper have a more nuanced interpretation of their results than mr. McClain.
flachspieler flachspieler 1/25/2017 11:03
@Jacob Woge:
it was German Grandmaster Dr. Helmut Pfleger back in the late 1970's or early 1980's.
Jacob woge Jacob woge 1/25/2017 11:01
I seem to remember a master who used tranquilizers to steady his nerves. Who in his narrative of the experiment wrote, "I was perfectly calm during the game. My heartbeat did not exceed 45 bps, even as I got mated."

But who it was escapes me. A name, anyone?
Jacob woge Jacob woge 1/25/2017 10:51
"So everyone went through the same protocol."

Is this the standard method of testing the effect of a substance? I would have thought, test group and control group.

Here, test group and control group are the same persons, unless i have misunderstood. But I realise this is difficult to apply in this particular setting.

“This suggests that neuroenhancers do not enhance the quality of thinking and decision-making per time unit but improve the players’ ability or willingness to spend more time on a decision and hence to perform more thorough calculations.”

Increased thinking time is not necessarily linked to more thorough calculations. Lack of confidence. Calculations going in a loop. Inability or unwillingness to make a move.

Some chess players would perform better if they played slower. Others would perform better if they played faster.
brownj brownj 1/25/2017 10:50
I doubt if the first statement is true:

"It is the first time that drugs have been found under rigorous scientific conditions to improve chess performance"

There is a whole body of research on this that goes back nearly a hundred years. Do a literature search. Holck, H. (1933). Effect of caffeine upon chess problem solving. Journal of Comparative Psychology, 15, 301–311.
Dylan McClain Dylan McClain 1/25/2017 10:12
A7fecd1676b88 Yes, you are arrogant and obnoxious, not merely confident. You stoop to insult ("Is English your first language?") when you are contradicted. I went back and read through your comments on other threads. You are consistently this way. Your superiority complex comes raging across in everything you write. Two last factual points about the study: The players on stimulants slowed down in all the games in which they were on stimulants, not merely the ones they lost on time. It was an across the board change in behavior. And to maxi80's question, each player took each of the drugs and the placebo as the study was conducted across several weeks. So everyone went through the same protocol. One last point, A7fecd1676b88. I know that you are going to write again -- you cannot let things drop because you are always right and must prove the rest of the world always inferior and always wrong. You are probably sick in some way that I cannot diagnose since I am not a psychiatrist. But I have come across people like you before on the Internet. Trying to have a real debate and exchange of opinion with someone like you is impossible. So, you are welcome to your delusions of superiority. Say what you want -- it amounts to nothing.
flachspieler flachspieler 1/25/2017 09:38
My uncle was a student in the late 1950's. He had problems in his written exams, and got Ritalin to improve the situation. He felt great all time during the only exam where he tested it. But at the end it turned out that he had stepped over time, having solved only about half of the exercises. Hands off !
AzingaBonzer AzingaBonzer 1/25/2017 09:26
@A7fecd1676b88 - Confidence and arrogance are the same underlying emotion. The difference is whether it is justified. Here, you have made approximately 0 arguments supporting your point, requested that someone read a book before engaging in an online discussion, repeatedly insulted anyone who disagrees with you, and have not even read the study at which your criticisms are directed. This is not the behavior of anyone who is even intellectually honest, much less justified in their "confidence". As such, I feel confident in stating that your criticisms deserve as much consideration as you say the study you were criticizing does--that is to say, precisely none.

@mrburns123 - It is true that studies are often less conclusive than we would like them to be. The correct response to this, however, is to reserve judgment and await further studies, not to apply blanket skepticism. For instance, consider the academic reaction to the EMDrive, and compare that to the popular reaction. The former was calm and considered; the latter, coolly condescending. Most commenters here seem to be indulging in the latter category of "skepticism", which is no way to conduct a proper discussion.
maxi80 maxi80 1/25/2017 09:26
I don’t know but did for example player 1,234 in the study play any n number of games UNDER the influence of those substances, and then the same player the same number of games WITHOUT using any of them…?! How did they carry it out exactly? Seems to me that any given player in the study ONLY played games using drugs, OR a placebo. Am I missing something? All this said, drugs ARE drugs. We have problem here.

Regards.
Aighearach Aighearach 1/25/2017 09:24
@Dylan McClain: Nobody is going to "read the study" when you really mean "buy the study." If we're suspicious that it even has value, why would we pay to read it? Surely there are much cheaper books that would have more value to us!
Aighearach Aighearach 1/25/2017 09:20
Massaging the results until a significant result comes out isn't caution, it is just garbage.
mrburns123 mrburns123 1/25/2017 09:00
As for the negative reactions to studies like these, I guess people have become suspicious of things proven by studies in general:
https://www.youtube.com/watch?v=42QuXLucH3Q "Is Most Published Research Wrong?" - Veritasium

Or the short version by Homer Simpson: https://www.youtube.com/watch?v=1j2Duy_xzEA

Maybe the chessbase-intro to the article shouldn't start with the word 'Proven', because that increases the expectations, on how definite that study is, by a lot.
Bertman Bertman 1/25/2017 08:52
@mrburns123

Actually it is a little more obvious than you think. 50% means a 50-50 score over a sample of 100, right? 58% means 58-42 or.... a difference, and thus increase of 16%.
dofski dofski 1/25/2017 08:50
If the stimulants cause players to think longer (and therefore more likely to lose on time) it could be expected that they will improve performance on this basis alone. However the authors of the study control for game duration and find an improvement ie for games lasting say 10 minutes the win rate for those taking the stimulants was better than those not, and so on for all game durations.

Surely even without stimulants if you matched players who by nature reflect at different speeds, controlling for duration, you would observe a similar effect if you truncate the games at the time limit, ie eliminate losses on time ?

Would it be interesting also to control for number of moves per game ?
A7fecd1676b88 A7fecd1676b88 1/25/2017 08:49
@Dylan McClain -- Confidence is not arrogance. You need to read Cargo again. You clearly learned nothing from it.

You still think 15 minutes was a flaw? That is not a promising statement. Maybe English is not your first language.....I would call 15 minutes a godsend, if it let them learn something new.

"The study noted that the players on the stimulants spent more time between moves 11 and 25, when the games tend to be complicated"
Shocking result. I'm out of my prep....I have to think. Did the study examine the depth of the players book knowledge, and if they were out of book…Lieb is not a chessplayer. We can say the answer is no.
Dylan McClain Dylan McClain 1/25/2017 08:33
mrburns123 Good. Then that suggests a significant bump. 60 Elo is not all-determining, but it would matter over time. Thank you for finding that.
Dylan McClain Dylan McClain 1/25/2017 08:31
A7fecd1676b88 I have. Why don't you read the study and get back to me. And stop being so arrogant.
Dylan McClain Dylan McClain 1/25/2017 08:30
A7fecd1676b88 The 15-minute time limit turned out to be a flaw because they did not expect the players on the stimulants to, of all things, slow down. The study noted that the players on the stimulants spent more time between moves 11 and 25, when the games tend to be complicated. This is where they got into trouble. To your suggestion about testing at different time limits, that might be a good way to do another study. It would be nice to know at what time the stimulants have their maximum effect. But, again, in defense of this study, they controlled for many factors and got a result they did not expect. As they have said, there is a lot more room for investigation of what the drugs can, and cannot, do.
mrburns123 mrburns123 1/25/2017 08:28
I got the +60 ELO from here:
http://www.swisschess.ch/wertungstabelle.html?old=L3NjaGFjaHNwb3J0L2ZsL3RhYmxlLnBocA,,
That seems to be the value for a 58.4% score.
A7fecd1676b88 A7fecd1676b88 1/25/2017 08:26
@Dylan McClain -- Read Feynman's 'Cargo Cult Science'. Then get back to me